Project title:€¦ · Web viewNineteen growers recorded yellow leaf spot on Cordyline (£119,437), three of which also recorded oedema (an additional £50,000); five recorded yellow

Project title: Cordyline and Phormium: pests, diseases and disorders

Project number: HNS 171

Project leader: Dr Jill England, ADAS

Report: Final

Previous reports: None

Key workers: Dr Jill England (principal investigator, case study)Dan Drakes (case study)John Atwood (case study)Neil Gray (case study)David Hutchinson (case study)Dr Charles Lane (FERA) (P&D analysis)Tricia Giltrap (FERA) (P&D analysis)

Location: Desk study / survey

Project co-ordinators: Dr Steve Carter, Fleurie Nursery, Eastergate Nurseries

David Hooker, Hillier Nurseries Ltd.

Paul Dyer, Star Plants.

Date commenced: 1 January 2009

Date completion due: 31 July 2009

Key words: Cordyline, Phormium, leaf spot, tip burn, stem rot, crown rot, disease, physiological disorder, oedema, pest, thrips, aphid, mealybug, two-spotted spider mite, slugs, snails.

Whilst reports issued under the auspices of the HDC are prepared from the best available

information, neither the authors nor the HDC can accept any responsibility for inaccuracy or

liability for loss, damage or injury from the application of any concept of procedure discussed.

The contents of this publication are strictly private to HDC members. No part of this

publication may be copied or reproduced in any form or by any means without prior written

permission of the Horticultural Development Company.

© 2009 Agriculture and Horticulture Development Board

All information provided to the HDC by ADAS in this report is provided in good faith. As ADAS shall have no control over the use made of such information by the HDC (or any third party who receives information from the HDC) ADAS accepts no responsibility for any such use (except to the extent that ADAS can be shown to have been negligent in supplying such information) and the HDC shall indemnify ADAS against any and all claims arising out of use made by the HDC of such information.

The results and conclusions in this report are based on an investigation conducted over several months. The conditions under which the experiment was carried out and the results obtained have been reported with detail and accuracy. However, because of the biological nature of the work it must be borne in mind that different circumstances and conditions could produce different results. Therefore, care must be taken with interpretation of the results especially if they are used as the basis for commercial product recommendations.


AUTHENTICATION

I declare that this work was done under my supervision according to the procedures described herein and that the report represents a true and accurate record of the results obtained.

Dr J. EnglandHorticultural consultantADAS UK Ltd

Signature .......................................................... Date .................................................

Report authorised by:

Dr T. O’NeillHorticultural Research ManagerADAS UK Ltd

Signature .......................................................... Date ................................................


Contents

Grower summary..........................................................................................................1

Headline...................................................................................................................1

Background and expected deliverables....................................................................1

Summary of the project and main conclusions.........................................................2

Financial benefits......................................................................................................2

Action points for grower............................................................................................3

Science section...........................................................................................................5

Introduction...............................................................................................................5

Methods....................................................................................................................6

Literature review.......................................................................................................7

Initial survey results................................................................................................20

Case study results..................................................................................................36

Pest and disease analysis report............................................................................51

Discussion..................................................................................................................53

Conclusions................................................................................................................58

References.................................................................................................................60

Appendices.................................................................................................................60


Grower summary

Headline

The most problematic pests, diseases and disorders to affect Cordyline and

Phormium cultivars have been identified:

Cordyline: two-spotted spider mite and the undiagnosed disorders: yellow leaf

spot syndrome, tip burn and ‘wobble’.

Phormium: Phormium mealybug and two-spotted spider mite.

Background

Recent mild winters and dry summers have created a resurgence of interest in

tropical-looking plants, including a range of Cordyline and Phormium cultivars,

resulting in increased sales which are of great value to the hardy ornamental nursery

stock industry. However, UK growers have reported major problems affecting their

production. This study was designed to provide information on the scale of current

problems, identify further investigations needed into the causes and the development

of production strategies to eliminate them.

The expected deliverables were:

To provide an overview of the major challenges encountered by Cordyline

and Phormium growers.

To carry out limited sample analysis of Cordyline plants affected with yellow

leaf spot syndrome (at the Food and Environmental Research Agency, FERA)

to identify any causal agents present.

To gain an understanding of the husbandry and crop protection techniques

currently in use to address these challenges.

To suggest production strategies and future targeted investigations to enable

these problems to be resolved.

© 2009 Agriculture and Horticulture Development Board 1

Summary

This study involved a review of information from literature, growers and consultants

relating to pests, diseases and disorders affecting Cordyline and Phormium

production. An initial grower survey, in which 44 Cordyline and Phormium growers

participated, provided an overview of the difficulties faced. Case studies targeting

eight growers from across the country then provided in-depth information concerning

current practice in producing these crops and combating the problems experienced.

Survey results

Problems highlighted as affecting production of quality Cordyline and Phormium

were:

Pests

Phormium mealybug (Balanococcus diminutus) and Cordyline mealybug (Balanococcus cordylinidis).

Two-spotted spider mite

Slugs and snails

Aphids, thrips, tortrix caterpillars, vine weevil and sciarid fly larvae (reported

not a serious risk to the crops)

Diseases and disorders

Yellow leaf spot syndrome / oedema

Other leaf spots

Tip burn

‘Wobble’ or ‘rock’ Crown, stem and root rots

Financial benefits

Financial benefits to growers obtained from resolving the issues raised in this report

include reduced wastage and increased profit margins for growers, and a premium

product for the customer. The results of this survey suggest that by controlling the

major issues reported (tip burn, yellow leaf spot syndrome, two-spotted mite and

Phormium mealybug) there could be a financial benefit of around £1.8 million each

year to the UK horticulture industry.


Action points for growers

A number of the conditions reported require further investigation. However, there are

some general action points and respondent comments that may help to improve crop

quality.

Yellow leaf spot syndrome / oedema control: do not over water, provide

adequate ventilation and spacing between plants, and where possible

increase light intensity during the late winter / early spring when these

symptoms tend to develop.

Leaf spot control: pay attention to water management in terms of application

timing and / or method. Avoid wetting leaves during irrigation where possible

and apply water early enough to enable leaves to dry off before temperatures

drop. Ensure the cause is correctly diagnosed by laboratory analysis so that

the appropriate control measures may be applied.

Phormium mealybug control: Key to controlling Phormium mealybug is to

quarantine new stock on arrival and inspect each plant for infestations, taking

particular care to look in leaf folds and at the base of the leaves. Infested

stock should not be allowed onto the nursery.

Two-spotted spider mite control: A number of predators are available for

control of two-spotted mite including Phytoseiulus persimilis, Amblyseius

andersoni, A. californicus, and Feltiella acarisuga, although some growers

have reported difficulty in adequately establishing predators in these crops.

There are also several acaricides that are approved for use on ornamental

plants under protection, including Apollo 50 SC (clofentezine), Masai

(tebunenpyrad) and Dynamec (abamectin). Before using any of these

acaricides in an IPM programme, their compatibility with any biological control

agents being used should be checked with the biological control supplier. The

pyrethroids including Gyro (bifenthrin) and Talstar 80 Flo (bifenthrin) are

effective but are not IPM-compatible. Experience has shown that the waxy

leaves of Phormium make good spray coverage difficult, and the addition of

an adjuvant such as Codacide may improve chemical control of two-spotted

spider mite.


Tip burn control: grower experience suggests that careful water management,

calcium supplements, foliar feeding, site selection (avoiding a high fluoride

level in the water) and temperature control may help to reduce tip burn.

Wobble or ‘rock’ control: plant Cordyline deeper to encourage lateral root

development nearer the base of the trunk to stabiliser plants. Planting depth

would vary depending on the maturity of the plant, but the critical point would

be to avoid burying the growing tip.


Science section

Introduction

Cordyline australis (New Zealand Cabbage Tree, Agavaceae), native to New

Zealand, Australia, India, South America and Polynesia, and Phormium tenax (New

Zealand Flax, Phormiaceae, revised from Agavaceae), native to New Zealand, are

both monocotyledonous evergreens highly regarded by gardeners for their

architectural merit (Armitage et al., 2005; Kelly, 1995).

Recent mild winters and dry summers have created a resurgence of interest in

tropical-looking plants, including a range of Cordyline and Phormium cultivars with

sales of great value to the hardy ornamental nursery stock (HONS) industry.

However UK growers have reported major problems affecting their production; the

main objective of this study was to identify the scale and causes of the major pest,

disease, virus and environmental factors implicated in causing the production of

substandard Cordyline and Phormium crops in UK HONS, and to provide growers

with technical advice to enable them to consistently produce crops of premium

quality.

Aims of the survey were:

To produce a review of literature, and information from growers and

consultants, relating to pests, diseases and disorders of these crops.

To provide an overview of the major challenges encountered by Cordyline

and Phormium growers.

To gain an understanding of the husbandry and crop protection techniques

currently in use to address these challenges.

To carry out limited sample analysis of affected plants to identify any causal

agents present.

To suggest future research needs to resolve these challenges and produce

best practice guidelines for growers.


Methods

A literature review of pests, diseases and disorders of Cordyline and Phormium and

related plants, entailed searches of scientific literature (Scopus and Science Direct),

HDC reports and the internet in general. Other horticulture consultants (John Adlam,

Dove Associates, Owen Jones (ADAS, retired) and Neil Hellyer, Fargro) were

contacted to provide their views on factors adversely affecting production of these

crops in the UK.

An initial survey proforma was constructed by Jill England (ADAS) (Appendix 1),

approved by the Steve Carter (project coordinator) and Scott Raffle (HDC) and

circulated to Hardy Nursery Stock grower members of the HDC in paper format (via

the HDC) for completion. Key Cordyline and Phormium producers who had not

responded were then contacted by telephone and email to ensure they were aware

of the survey and had the opportunity to participate. This survey aimed to gather

broad information on the major problems affecting production of Cordyline and

Phormium crops grown in the UK, providing information on their scale and causes.

Eight nurseries were selected to take part in an in-depth case study (Appendix 2);

these were a geographical cross section of nurseries involved in different stages of

production, with and without the major pest, disease and disorder problems to enable

a balanced review of the cultural practices being used commercially. A proforma was

again constructed by J. England (ADAS) and approved by the project coordinators

(Steve Carter and Dave Hooker) and used as a basis for on-site interviews by ADAS

consultants (John Atwood, David Hutchinson, Neil Gray, Dan Drakes and Jill

England). Chemicals reported within the initial survey and case studies are those

noted by growers and do not imply current approval for use under protection within

the UK.

Samples of Cordyline affected by yellow leaf spot syndrome were collected during

the case studies and submitted to the Central Science Laboratory, York (FERA) for

further investigation. They were subjected to analysis for pests, diseases, and

viruses, including cellular examinations using a range of modern (PCR, transmission

electron microscopy, scanning EM, fatty acid profiling, pyrosequencing etc) and

conventional diagnostic techniques.


Literature review

Pests

Several pests have been recorded on Cordyline and Phormium, in particular the

Phormium mealybug and two-spotted spider mite, slugs and snails but also aphids

and thrips to a lesser degree.

Phormium mealybug ( Balanococcus diminutus Leonardi, syn. Trionymus diminutus Leonardi) and Cordyline mealybug (Balanococcus cordylinidis )

The mealybug (including both Phormium and Cordyline) is a member of homoptera,

the scale insects, a large group which includes the armoured scales, soft scales and

mealybugs with piercing, sucking mouth parts and which are sexually dimorphic (i.e.

the male and female are different). Mealybug is reportedly more of a problem on

Phormium than Cordyline.

The Phormium mealybug is primarily associated with Phormium tenax J.R. & G.

Forst (New Zealand Flax). (Bartlett, 1981). It was first identified in the UK in October

1977 on a consignment of P. tenax ‘Goldspike’ at a nursery in Diss, Norfolk, imported

from New Zealand, and from there it quickly spread throughout the UK (Bartlett,

1981). The Phormium mealybug is an important pest for several reasons, including

its ability to survive low temperatures, overwintering both inside and outside in many

areas of the UK (Buczacki and Harris, 2005).

The Cordyline mealybug is associated with Cordyline australis (G. Forst) Endl. and

has not been identified in the UK by FERA at present. Until 1987 Balanococcus

cordylinidis was considered to be a subspecies of Balanococcus diminutus. They

were separated in 1987 and there remains confusion in the literature. There are

morphological differences and laboratory verification would be required to

differentiate between the two species (Malumphy, 2009). The glasshouse mealybug

(Pseudococcus viburni) is also found associated with Cordyline spp.

Mealybug adult females and nymphs cover themselves in a waxy, mealy substance

which insecticides have difficulty penetrating, preventing direct contact with the

mealybug (Gavin, 1992). In Phormium, mealybugs secrete themselves deep within

the leaf axils. Phormium leaves are covered with a waxy cuticle which prevents or


reduces penetration by systemic chemical controls and which it is difficult for

insecticides to adhere to.

A number of biological control agents are approved and effective against various

mealybug species in the UK, including predators and parasitic wasps. However, the

parasitic wasps are effective on specific mealybugs, for example Leptomastix

dactylopii is host specific to citrus mealybug and Leptomastix epona is host specific

to vine mealybug, and neither would control Phormium mealybug (Copland, 2008).

Another biological control, Cryptolaemus montrouzieri Mulsant (Coleoptera:

Coccinellidae), a small coccinellid predatory beetle (ladybird) is effective against all

mealybugs and used against pests on crops grown under protection in the UK. It has

dark brown wing covers, an orange head and posterior and is around 4 mm long. C.

montrouzieri lays yellow eggs among the woolly egg masses produced by female

mealybugs, which hatch into white larvae that are covered with wax-like filaments,

resembling adult mealybugs. Adults and larvae feed on all developmental stages of

the mealybug, and fly in search of new colonies (Koppert, 2007). However, they are

largely inactive below 150C, are most effective between 210C and 300C F (BCP

Certis, 2006) and have difficulty in getting down into the leaf axils where mealybugs

tend to hide (Hellyer, 2008).

Previous projects studying the mealybug Pseudococcus viburni found on UK tomato

crops (Croft, 2007; de Courcy Williams, 2002; Morley and Jacobson, 2008) found the

most effective Integrated Pest Management (IPM) compatible treatment for control

was the selective insect growth regulator buprofezin (Applaud). Applaud has a

particularly good effect where plants are covered with fleece for a week to take

advantage of the vapour action which then penetrates into the Phormium leaf axils

(Hellyer, 2008). However, some resistance has been recorded and also approval of

this product has been revoked with a final use date of 30 March 2010 (Pesticides

Safety Directorate, 2008). The biological controls investigated within these projects

were parasites (Leptomastix epona, Anagyrus pseudococci and Pseudaphycus

maculipennis), predatory mites (Hypoaspis miles and H. aculeifer) which were found

unsuitable, and a predatory lacewing (Chrysoperla carnea) which required further

investigation. Application of the entomopathogenic fungus Verticillium lecanii

(Mycotal WP) following Savona provided 100% mortality in some instances, but

results were variable. The entomopathogenic fungus Beauveria bassiana (Naturalis

L and Botanigard WP) did not provide significant control. © 2009 Agriculture and Horticulture Development Board 8

Savona (2%) reduced first instar mealybug numbers by 93%, but had variable effects

on mealybugs at other growth stages (2% and 4% dilutions gave 30-60% control and

40-100% control respectively) and would require multiple applications for effective

control. Crop oil (a paraffin oil), effectively removed wax from motile and egg stages

of mealybugs leading to mortality. Although other products tested (Hyvis 30

Emulsion, Jet 5, undiluted vinegar and Eradicoat T) provided some control on

cropping and non-cropping areas (per their approvals) the level of control was

inadequate for commercial tomato crops. Hortichem Spraying Oil and Horticide were

ineffective. The antifeedant Chess (pymetrozine) provided some control, but was

inadequate for a commercial crop. A pheromone used for trapping the citrus

mealybug (Plannococcus citri) did not appear effective for P. viburni (Croft, 2007; de

Courcy Williams, 2002; Morley and Jacobson, 2008).

Two-spotted spider mite ( Tetranychus urticae )

Two-spotted spider mite is well-known as it is has a large number of host plants,

including Cordyline and Phormium, and is the most common of the spider mite

species found in UK horticulture. Mite feeding damage is caused by the rasping of

the lower leaf surface with their mandibles; they then suck the sap from the leaf and

leave small pale spots over the surface. Heavy infestations can result in whole

leaves turning yellow and the plant dying; large numbers of mites can be found at

shoot tips associated with silk webbing. They are easily spread throughout the

nursery (Buxton, 2009).

There are a number of biological control options for two-spotted spider mite:

Phytoseiulus persimilis, Amblyseius andersoni, A. californicus, A. swirski and Feltiella

acarisuga. Of these P. persimilis is the mainstay, although it will only remain when

there is prey present and is less effective at high temperature. A. andersoni and A.

californicus are useful as they feed on a range of prey, and F. acarisuga feeds on all

stages of spider mite. There are several acaricides that are approved for use under

protection including Apollo 50 SC (clofentezine), Masai (tebunenpyrad) and Dynamec

that are reasonably compatible with IPM programmes. Pyrethroids including Gyro

(bifenthrin) and Talstar 80 Flo (bifenthrin) are effective but are not IPM compatible

(Buxton, 2009).


Slugs and snails

Slugs and snails are common pests in the UK and affect both Cordyline and

Phormium among many plant species, particularly soft, leafy specimens. Symptoms

are similar for both pests, as they each graze on leaves and have a rasping, toothed

tongue with which they remove plant tissue, generally feeding at night. A distinctive,

persistent slime trail is often used to identify the cause of this feeding damage. Slug

and snail activity is more severe during warm humid periods, and numbers can be

reduced by good nursery hygiene, removing plant litter, moss, liverwort, algae

(Buczacki and Harris, 2005).

Several control measures are available including slug pellets, active ingredients

metaldehyde, methiocarb and ferric sulphate (Ferramol); Ferramol is claimed to be

the more environmentally friendly option. The biological control product Nemaslug,

containing the nematode Phasmarhabditis hermaphrodita, is becoming more widely

used in the industry and is effective against both slugs and snails. The nematodes

are applied when slugs and snails are active in growing media temperatures between

5 0C and 25 0C (Bennison and Schüder, 2006). A number of growers reported in this

survey that they use Croptex Fungex against slugs and snails. This product, along

with other treatments, has been shown to have a barrier effect, an antifeedant effect,

and treated surfaces have been shown to increase the mortality of slugs and snails

(Schüder et al., 2004). Croptex Fungex has an approval for use as a fungicide.

Aphids

A number of aphids are found in the UK, with size, colour and host range varying

between species. They feed on all plant parts by sucking sap via a stylet which is

inserted into plant tissue; excess sap is secreted as honeydew. Aphids cause

distortion of new growth, the honey dew encourages colonisation of sooty mould, and

they are responsible for viral transmission between plants (Buczacki and Harris,

2005).

There are a number of biological controls available, including the parasitic wasps

Aphidius colemani and Aphidius ervi, which only parasitise specific aphid species,

and predators such as the midge Aphidoletes aphidimyza, lacewings, hoverflies and

ladybirds, which prey on all aphid species. The insect-pathogenic fungus Verticillium

lecanii (Vertalec) is also available but not widely used as it requires high humidities in

order to be effective. The main aphid species found on Cordyline, particularly C. © 2009 Agriculture and Horticulture Development Board 10

australis ‘Torbay Dazzler’ (C. australis seems to be unaffected) is Rhopalosiphum

padi (the bird cherry aphid), which is parasitized by A. colemani (Buxton, 2009).

Chemicals suitable for use in IPM systems are Chess (SOLA 2834/08, pymetrozine),

Eradicoat, Majestik, Savona and SB Plant Invigorator. Aphox (pirimicarb) is selective

for aphid, but Aphis gossypii and some strains of Myzus persicae are resistant.

Nicotine 40% shreds, Calypso (SOLA 3728/06, thiacloprid) and Gazelle (acetamiprid)

are moderately harmful to beneficials. The pyrethroids and Spruzit (pyrethrin) are

also effective but there has some resistance seen in Aphis gossypii and some

strains of Myzus persicae (Pesticides Safety Directorate, 2008).

Thrips

A number of thrips species may be found in glasshouses, including western flower

thrips (Frankliniella occidentalisi) and onion thrips (Thrips tabaci). Feeding damage

is caused by the piercing of plant cells and sucking sap, which leaves small

irregularly shaped white or silvery marks on the leaves and on which small black

faecal specks can usually be seen. Thrips can cause further major problems by

acting as a virus vector.

A range of controls are available for thrips. Biological controls available are the

predatory mites Amblyseius cucumeris, A. Swirskii, Hypoaspis miles, H. aculeifer,

Orius laevigata, O. majusculus, the rove beetle Atheta coriaria, lacewings, the

nematode Steinernema feltiae, and the insect-pathogenic fungus Verticillium lecanii.

Chemical controls safe in IPM systems include Eradicoat, Majestik, and Nemolt

(SOLA 2120/07). Other chemicals include Conserve (spinosad), Nicotine 40%

shreds, Dynamec (abamectin) and Calypso (SOLA 3728/06, thiacloprid) (Pesticides

Safety Directorate, 2008). Several applications are normally required to bring the

thrips population under control, and products should be rotated in a programme to

reduce the risk of resistance developing.

Diseases

There are numerous reports of fungal and other species linked to Cordyline and

Phormium worldwide, including a checklist of fungi found on these species in New

Zealand (McKenzie et al., 2005). Common saprophytes and cosmopolitan species

that do not impact on plant quality in the context of this report have not been

included.


Management of fungal diseases can often be achieved by attention to the growing

environment. Fungal pathogens require water in varying quantities to establish and

proliferate. Providing unfavourable conditions by, for example, irrigating (overhead)

early in the day rather than in the evening to maintain drier leaf surfaces, and by

reducing humidity by providing adequate ventilation and spacing between plants

helps to control leaf and stem rots. An open growing media and adequate drainage

maintains a drier root environment and reduces root and collar rots. Good practice

suggests that new stock should be segregated and inspected on arrival and rejected

if affected by any unacceptable pests or diseases to prevent the nursery becoming

infested. Good nursery hygiene and weed control also help by removing decaying

plant debris and alternate hosts which may harbour pathogens and overwintering

spores.

There are various chemical control options and consideration of the taxonomic

grouping of pathogens can be helpful in selecting the most appropriate. Accurate

identification of pathogens is critical to providing the most appropriate treatment and

often requires laboratory analysis. In general, for example, oomycetes may be

treated with products such as Filex (propamocarb hydrochloride) or Aliette 80 WG

(fosetyl-aluminium), Rhizoctonia with Rovral WP (iprodione), Amistar (SOLA

0443/09, azoxystrobin) or Basilex (tolclofos-methyl), rust with Amistar (SOLA

0443/09, azoxystrobin)), Bravo 500 (chlorothalonil) and ascomycetes such as

Colletotrichum sp. or Cercospora sp, with Octave (prochloraz) (Pesticides Safety

Directorate, 2008).

Samples of Cordyline and Phormium that have been submitted to the FERA plant

clinic for investigation provide a historical record of diseases experienced on these

plants in the UK. A number of leaf spots occur on Cordyline, including the fungal

pathogens Glomerella cingulata, Cercospora sp., Fusarium moniliforme, Phyllosticta

dracaenae, Phytophthora parasitica; the bacteria Erwinia spp. and Impatiens necrotic

spot virus (INSV) (Lane, 2009). Cordyline are also affected by yellow leaf spot

syndrome, the cause of which remains to be established.

Several leaf spots have also been found in Phormium in the UK, the most common of

which is Kirramyces phormii, but also Glomerella cingulata. There are reports of

fungal pathogens including Phoma sp., Cercospora sp., Stenella sp. and Phyllosticta

sp. causing leaf spots; bacterial leaf spots due to Xanthomonas campestris pv

phormicola and a Pseudomonas fluorescens/marginalis complex (Lane, 2009). © 2009 Agriculture and Horticulture Development Board 12

The following is a brief summary of information relating to the causes of diseases

found on Cordyline and Phormium worldwide (not necessarily reported in the UK):

Botrytis cinerea is a ubiquitous pathogen on many hosts and has been isolated

from leaf lesions of Cordyline. In its teleomorphic form (Botryotinia fuckeliana) this

pathogen has been associated with damping-off diseases of seedlings in

Cordyline and Phormium (McKenzie et al., 2005).

Candidatus Phytoplasma australiense has been linked to the sudden decline,

collapse and death of Cordyline plants in New Zealand (North Island); this

phytoplasma has also been linked to Phormium yellow leaf and is spread by sap-

sucking insects (Andersen et al., 2001; Liefting et al., 1998).

Cercospora sp. is seen on Cordyline as pale brown or reddish rectangular leaf

blotches which are limited by leaf veins (McKenzie et al., 2005).

Colletotrichum acutatum has been isolated from leaf spots of Phormium

(McKenzie et al., 2005).

Colletotrichum phormii has been isolated from Phormium plants originating

from the UK by USDA microbiologists and in 2006 the US prohibited entry of

Phormium tenax infected with this pathogen. It has numerous synonyms and

appears to occur only on Phormium spp. (Farr et al., 2006).

Cylindrocarpon scorparium is often associated with damping-off diseases of

Cordyline seedlings (McKenzie et al., 2005).

Erwinia spp. Symptoms of this bacterial infection include a wet leaf spot, stem

rot and root rot with a distinctive smell which tends to occur on infected cuttings.

Lesions are usually water soaked and slimy (Henley et al., 2009). There are

currently no chemical control options for Erwinia spp.

Fusarium moniliforme causes reddish-brown round to oval spots, sometimes

with a yellow halo and which tend to occur near the growing tip of immature

leaves, on either leaf surface (Buczacki and Harris, 2005; Henley et al., 2009). Fusarium crookwellense has been found in New Zealand associated with

rotting of central leaves at the apex of young Cordyline plants (McKenzie et al.,

2005). Fusarium oxysporum has been identified causing plant collapse in

Cordyline (Jones, 2008).

Glomerella cingulata (Ascomycete) is pathogenic on many hosts including,

Cordyline and Phormium. Colletotrichum gloeosporioides is the asexual stage.

The leaf spots caused by Glomerella cingulata are an elongated diamond shape,

and are found on both upper and lower leaf surfaces; on the upper surface they © 2009 Agriculture and Horticulture Development Board 13

are pale brown with a dark brown margin and they are lighter coloured on the

lower surface with many perithecia and a dark margin.

Impatiens necrotic spot virus (INSV) causes leaf spots, ring spots and stunting

in a range of plants and has been recorded on Cordyline (Roggero et al., 1999).

Thrips, including Frankliniella occidentalis (Western flower thrips) and Thrips

tabaci (onion thrips) are the virus vector, therefore these need to be monitored

(blue sticky traps) and controlled to prevent spread of the virus as there is no

treatment for the virus itself (Buczacki and Harris, 2005).

Kirramyces phormii. Phormium is the host of Kirramyces phormii, now

Phaeophleospora phormii (Crous et al., 1997). It causes an oval, reddish or

purple leaf spot on the upper leaf surface of Phormium and dark brown to black

on the lower surface (McKenzie et al., 2005).

Periconiella cordylines causes an indistinct, reddish brown leaf speckle on

Cordyline. P. phormii (syn. Stenella dianellae), causes a large, distinctive

reddish purple blotch on the lower leaf surface, and is endemic and widespread

throughout New Zealand (McKenzie et al., 2005).

Phoma spp. Various undetermined Phoma have been isolated from leaf spots in

New Zealand (McKenzie et al., 2005). Phoma nebulosa is recorded on Cordyline

(Kinsey, 2002).

Phyllosticta dracaenae causes circular or irregularly shaped leaf spots, brown

with purple borders and yellow halos which vary in size between 1-5 mm in

diameter and occur mainly on older leaves (Henley et al., 2009). P. cordylinophila has been found on Cordyline in Portugal, Hawaii and Japan and

causes reddish brown circular or irregular leaf spots, (McKenzie et al., 2005).

Phytophthora parasitica produces lesions, initially water soaked and brown with

irregular margins and tends to occur on the lower leaf surface. (Henley et al.,

2009). Phytophthora spp. can also be the cause of root, crown and basal stem

rot. Symptoms are poor growth, wilting and plant collapse. Roots become water-

soaked, brown or black and soft; the stem base becomes discoloured reddish-

brown (O'Neill and Ann, 2004).

Pythium spp. Root and basal stem rot produces similar symptoms to

Phytopthora on the aerial part. Affected roots become grey or brown, shrivelled

and water soaked; symptoms are sometimes confined to thin lateral roots or root

tips. Pythium also causes damping-off in seedlings and cuttings (O'Neill and Ann,

2004).

Pseudomonas spp. (bacteria) have been isolated from Cordyline, but there is

little descriptive information (Madhusmita et al., 1999).© 2009 Agriculture and Horticulture Development Board 14

Rhizoctonia solani causes damping-off of seedlings and cuttings, root and

crown rots, and occasionally leaf and stem blight. The stem base can be

discoloured and restricted at the growing media surface (wire-stem), and on

mature plants may appear as brown sunken lesions on the stem at or just above

the growing media surface. Dry lesions which progress inwards may occur on

cutting stems and fungal hyphae may be visible (O'Neill and Ann, 2004).

Sphaeropsis cordylines is currently only known from New Zealand, but causes

large dark brown oval leaf spots with dimensions up to 20 x 10 mm on Cordyline

(McKenzie et al., 2005).

Uredo phormii is a rust fungus, widespread in New Zealand but not common,

and found only on Phormium (McKenzie et al., 2005).

Yellow leaf spot syndrome (Figure 1) is found in Cordyline. Symptoms are

small raised pustules, initially chlorotic, sometimes appearing water-soaked and

sometimes becoming necrotic. Although this is sometimes thought to be due to

rust, no rust pathogens have been recorded on Cordyline. Microscopic

examination has revealed swollen plant cells that could suggest a hypersensitive

response to infection, pest feeding damage or physiological disorder such as

oedema (Lane, 2009).

a b c

Figure 1 Cordyline plants showing symptoms of yellow leaf spot syndrome, (a) and (b)(Bartlett, 1981; England, 2007; Lane, 2009) (c)(England, 2007)


Disorders

Oedema

Oedema typically occurs under conditions of warm, moist soil and high humidity,

when roots absorb water faster than they can use it or it can be lost through

transpiration. This causes plant cells to swell as water continues to be taken up,

resulting in blistering and chlorotic spots which may occur on the leaves, stems,

flowers or fruit of susceptible plants (San Marcos Growers, 2005).

Oedema is common on Agave attenuata and A. desmettiana ‘Joe Hoak’ (San Marcos

Growers, 2005), close relatives of Cordyline and Phormium, and is well documented

in numerous other species including Eucalyptus (Pinkard et al., 2006) Solanum

tuberosum (potato) (Seabrook and Douglass, 1998), ivy leaf geranium (Rangarajan

and Tibbitts, 1994), Solanum melongena (aubergine) (Eisa and Dobrenz, 1971) and

Begonia elatior (Papenhagen, 1986).

Development of oedema was increased by high relative humidity and light quality (no

UV-B) (Lang and Tibbitts, 1983; Papenhagen, 1986), and increased with declining

light intensity in tomato (Sagi and Rylski, 1978). Oedema was reduced when light

quality was adjusted using yellow filters in potatoes (Lang and Tibbitts, 1983;

Seabrook and Douglass, 1998) and with addition of far-red to red irradiance, or by

providing far-red irradiance immediately after red irradiance (Morrow and Tibbitts,

1988). Oedema has been successfully induced in leaf discs of various species

(Eucalyptus globus, Ipomoea batatas, Lycopersicon esculentum, Pelargonium

peltatum, Populus tremula, Solanum tuberosum) by controlling humidity, UV radiation

and temperature in growth chamber experiments.

Poor leaf colour

A dark, dull appearance to Cordyline is attributed to light intensity (high or low), low

fertiliser levels or high temperatures, and there are recommendations that shade

should be applied in high summer light levels and supplementary light applied in

winter, and that moderate fertiliser levels and temperatures should be maintained

(Moorman, 2009).


Tip death

Very young leaves have been reported with leaf tip damage attributed to fertiliser or

leaf shining chemicals. It was suggested that fertilisers should not be applied over

the growing point or young leaves (Moorman, 2009).

Nutritional influences

Nutrient deficiency and toxicity can be a cause of leaf margin and tip browning,

including calcium, potassium and boron deficiency, and fluoride and boron toxicity.

Whilst there are numerous reports of these nutritional disorders in both

dicotyledonous and monocotyledonous plants, only fluoride toxicity has been

specifically reported in Cordyline and none in Phormium.

Fluoride toxicity

Much of the recent interest in the phytotoxic effects of fluorides has developed as a

result of high levels of plant injury found near large cities and where industries such

as aluminium smelting and phosphate extraction are based; fluoride is released when

clays, rocks or other material containing it are heated, or it is used as a flux and then

released into the air (Treshow, 1971). Plants express a large range of sensitivity to

fluoride with the most sensitive, such as Lolium perenne, Gladiolus spp. and

Hypericum perforatum, cited as indicators of fluoride pollution (Fornasiero, 2001).

Phormium tenax and Cordyline australis are listed as sensitive to fluoride (Doley et

al., 2004; Weinstein and Davison, 2003).

Fluorides are absorbed by plants from the atmosphere via foliage, through the

stomata, and from substrates (originating from the substrate or water) via the roots,

with each route producing different patterns of necrosis within leaves; damage is

mainly confined to leaf tips and margins in the former, whilst with substrate-derived

fluoride necrotic areas appear more random within the leaf and are lacking in the

margins (Woltz, 1964). Fornasiero (Fornasiero, 2001) observed that in Hypericum

perforatum sodium fluoride (NaF) from the substrate entered the plant through the

root and travelled in the xylem via the transpiration stream to leaf tips and margins,

where greatest evaporation occurs. There does not appear to be movement of

fluoride downwards from leaves to roots (Brennan et al., 1950).


Typical macroscopic symptoms of fluoride toxicity are tip and margin necrosis,

commonly termed ‘tip burn’, with a distinct reddish-brown line separating it from

healthy tissue; it occurs in both monocotyledons and broad leaved plants. The most

severe symptoms are reported in fully expanded, middle aged leaves, with only tip

necrosis found in older and young leaves (Fornasiero, 2001), although this varies

between plant species; in Pinus spp. younger leaves are more susceptible (Davison

et al., 1974). Symptoms progress through chlorosis and desiccation of tissue which

becomes brown and necrotic.

Microscopic changes in the ultrastructure of Hypericum perforatum due to fluoride

toxicity are distortion of the leaf epidermal layers, mesophyll cell collapse, and

detachment of the plasma membranes from cell walls; alteration of chloroplasts and

an increase in plastoglobule (lipoprotein particles within chloroplast) number and

size. Presence of the antioxidant superoxide dismutase content decreases, reducing

the plant’s ability to counteract reactive oxygen species. Chlorophyls a and b, and

carotenoid content are significantly reduced (Fornasiero, 2001).

Leaf necrosis due to fluoride toxicity has been recorded in a number of

monocotyledons such as Gladiolus (Woltz, 1964), Freesia (Wolting, 1975) and

Cordyline (Conover and Poole, 1971; Fornasiero, 2001), and dicotyledons such as

Chrysanthemum and Antirrhinum (Marousky and Woltz, 1975).

Conover and Poole (1971) found Cordyline terminalis ‘Baby Doll’ sensitive to fluoride,

developing foliar necrosis during propagation in fluoride levels above 0.25 mg L -1 in

soil or water; severity increased with lower substrate pH and with reduced light levels

(shaded glasshouse conditions compared with lighted air conditioned laboratory

conditions). Necrosis also occurred in misted cuttings in vermiculite, perlite and

Terragreen, but not at significant levels in various barks and peats tested (Poole and

Conover, 1975).

The addition of superphosphate (3.80 kg m-3, 1.5% fluoride) has been found to

increase necrosis and tissue fluoride content of cuttings of Cordyline terminalis ‘Baby

Doll’ grown in German peat and Turface. The effect was reduced by

supplementation with calcium sulphate and magnesium sulphate treatments, and in

each case as the dose was increased (1.9 kg m-3 to 3.8 kg m-3) less necrosis was

recorded (Poole and Conover, 1975). Materials used in potting mixes with fluoride

rates over 100 mg L-1 dry weight, which are considered high, include superphosphate © 2009 Agriculture and Horticulture Development Board 18

(2600 mg L-1), diammonium phosphate (2000 mg L-1) and triple superhosphate (1600

mg L-1) (Bunt, 1988). In soils, fluoride and calcium can combine to form insoluble

calcium fluoride, rendering the fluoride unavailable to plants. There has been

concern that the level of fluoride in perlite may cause phytotoxicity, however this was

dismissed by Bunt (1988) as perlite has minimal cation exchange capacity and low

fluoride content (17 mg L-1) depending on perlite source.

Fluoride toxicity in all crops may be avoided by raising the pH of the growing media

to 6.0 to 6.5, using phosphoric acid instead of superphosphate and avoiding irrigating

with water with greater than 0.25 mg L-1 fluoride (Bunt, 1988). The recommended

maximum fluoride level for irrigation water is 1.0 mg L-1 (Holmes and Adlam, 2006).

In the UK a number of water authorities add fluoride to mains water to reduce teeth

decay in children. Where fluoridation does take place the concentration must be

maintained at 1.0 mg L-1 with a maximum concentration of 1.5 mg L-1 permitted under

the Water Supply (Water Quality) Regulations 2000 in England. The majority of the

UK has levels below 0.49 mg L-1; whilst there appears to be areas where levels reach

1.0 mg L-1 (Cheshire, Nottinghamshire, Leicestershire, West Midlands,

Worcestershire, Suffolk, Cambridgeshire, Bedfordshire, Essex, Northamptonshire

and Berkshire); and 1.5 mg L-1 (Berkshire, Essex, Nottinghamshire, Leicestershire

and Northamptonshire) (Defra, 2008). The British Geographical Survey provides

data derived from 30,000 analyses indicating fluoride levels in the majority of UK

streams range from below 0.05 mg L-1 in areas of Wales, Cumbria and Scotland to

above 0.35 mg L-1 in eastern and south eastern England, but does not provide a

precise maximum level (British Geological Survey, 2005). In the UK almost all mains

water supplies have a pH greater than 7 as suppliers add alkali to adjust the pH of

water before it leaves the water treatment works (The British Fluoridation Society,

2009). This suggests that UK water supplies could have fluoride levels greater than

the 0.25 mg L-1 recommended by Bunt (1988), particularly where mains water is

fluoridated to 1.0 mg L-1 or borehole / reservoir water has a high natural level of

fluoride, and this could cause tip burn on fluoride-sensitive Cordyline and Phormium

crops.

Calcium deficiency

Calcium deficiency has not been reported in Cordyline or Phormium. In general,

calcium deficiency symptoms in vegetative growth are seen as stunting of plants and

pale leaf margins followed by necrosis, mainly in young leaves; leaves may also curl


inwards, and plant tip death occurs in acute cases. Roots are also affected, with

young roots and root hairs dying and older roots turn brown (Bunt, 1988). Calcium

deficiency has been observed in a range of plant species including Cornus alba,

Hibiscus syriacus, Hydrangea paniculata ‘Grandiflora’ (Aenderkerk, 1997), lettuce,

cucumber, tomatoes, carrots, cauliflower, strawberries (Bould et al., 1983).

Boron deficiency and toxicity

No literature was found relating boron toxicity or deficiency to either Cordyline or

Phormium. Boron deficiency symptoms vary between plant species, but can include

leaf chlorosis of young leaves and stems, tip burn and weak growth in rice (Bunt,

1988; Yu and Bell, 1998).

Boron toxicity causes narrow brown or black leaf edge necrosis in older leaves

(Bould et al., 1983); boron is carried in the transpiration stream and deposited at leaf

margins and causing areas of high boron concentration, as seen in sensitive plants

e.g. Chrysanthemum, Poinsettia and Zinnia. Bunt ( 1988) recommends boron

application as frits, as the slow release action reduces the risk of toxicity.

Potassium deficiency

No literature was found relating to potassium deficiency in Cordyline or Phormium.

Potassium is involved in numerous cell functions including transport of sugars around

the plant. Deficiency may be expressed initially by browning of the leaf margin

followed by necrosis of the leaf edge and progresses to interveinal areas (Bragg,

1998). Potassium is very mobile, causing deficiency symptoms in older leaves as the

nutrients are preferentially mobilised from old to new leaves (Taiz and Zeiger, 2006).

Initial survey results

The respondents

44 growers participated in the initial survey, spread throughout the UK (Table 1). Of

the growers who responded, 34 grew Cordyline and 36 grew Phormium. A number of

growers were not able to answer all of the questions. The geographical spread of

growers selected for the case studies is shown in Table 2. Growers have on

occasion mentioned chemicals which have been revoked and this has been noted

within the text.


Table 1. Geographical spread of growers who participated in the initial survey

Southeast Southwest Northeast Northwest

Kent Cornwall North Yorkshire West Yorkshire

Surrey Devon Lincolnshire Lancashire

West Sussex Dorset East Yorkshire Cheshire

Somerset

East West South Scotland

Rutland Herefordshire Hampshire Glasgow

Suffolk Worcestershire Isle of Wight

Norfolk Staffordshire

Cambridgeshire West Midlands

Hertfordshire Gwynedd

Table 2. Geographical spread of growers who participated in the case studiesWest East South

Gwynedd Suffolk Hampshire

Herefordshire

Southeast Northeast Southwest

West Sussex East Yorkshire Dorset

Cordyline

Growers were asked to provide details of the major Cordyline varieties they grow

(Table 3) and their provenance (Table 4). Where growers had sourced the same

variety from more than one producer the variety was only counted once. Where a

grower had sourced more than one product line from a supplier, each was included

individually. A total of thirty three growers responded.

Where UK was stated as the country of origin plants may have been produced by

tissue culture abroad then grown on in plugs in the UK until distribution as UK-

produced product. Two nurseries who replied were unable to provide this

information. Figures represent the number of times a variety of Cordyline was

sourced from the country of origin (Table 4).


Table 3. Cordyline varieties grown by the respondents

Variety No. of growers Variety No. of

growers

australis 27 ‘Firecracker' 2

australis 'Red Star' 23 australis 'Atropurpurea' 1

australis 'Torbay Dazzler' 20 ‘Purple Tower' 1

‘australis 'Sundance' 9 australis 'Peko' 1

‘Southern Splendour' 6 australis 'Pink Stripe' 1

australis 'Torbay Red' 5 australis 'Red Sensation' 1

australis Purpurea Group 4 ‘Eurostar' 1

‘Sunrise' 4 ‘Eurostripe’ 1

australis 'Purple Sensation' 3 ‘Dark Star' 1

australis 'Pink Passion' 3 ‘Red Comet' 1

australis 'Pink Champagne' 2 'Cherry Sensation' 1

australis 'Sparkler' 2 ‘Red Festival Grass' 1

Table 4. Country of origin of Cordyline grown in the UK

Country of origin No. growers Country of origin No. growers

UK 33 Italy 3

Holland 12 Ireland 2

China 8 Australia 1

Spain 5 New Zealand 1

India 4

Growers provided details of the companies from which they sourced their Cordyline

stock. A total of 35 different suppliers were listed by growers, who supplied five

different categories of product (Table 5). Four nurseries did not provide specific

supplier information, either leaving the space blank or recording ‘various’.

Table 5 . Categories of Cordyline suppliers

Supplier category No. suppliers

Seed suppliers 5

Micro-propagators / plug producers 13

Liner producers 9

Suppliers of plants larger than liners 9


Growers reported that a total of 924,663 Cordyline were grown and 866,502 sold by

them each year. One grower did not respond to this question. Growers were asked

to state how many Cordyline they produce and purchase at different production

stages (Table 6). Data was provided by 26 growers.

Table 6. Total number of Cordyline either produced or purchased by growers at each

production stage.

No. of plants

Purchase Produce

Plug 203,300 536,000

Liner 300,200 110,850

1-3 L 265,510 77,564

4-5 L 37,000 250

> 5L 7,315 2,429

Growers were asked to indicate the pests and diseases observed on their Cordyline

crop and the success of any control measures used. Level of success was graded

into ‘Good’, ‘Moderate’ and ‘Poor’, and some measures fell into multiple categories

as growers had mixed success (Table 7). Eleven Cordyline growers reported no pest

problems. The majority could not give a precise cost of crop value affected, but the

total figures provided have been stated. Pests had affected all crop stages. Not all

growers gave an indication of success. Croptex Fungex and Cuprokylt have

approvals for use as fungicides, however growers noted in the survey that they were

used against slugs and snails.

Growers also provided details of the diseases or disorders observed on their

Cordyline crop and the success of any control measures used (Table 8). Eight

growers recorded no disease problems on Cordyline. The majority could not give a

precise cost of crop value affected, but the figures provided have been stated.

Diseases had affected all crop stages from mature plugs to finished product. Growers

have registered problems with yellow leaf spots and oedema, but they may refer to

the same symptoms in some instances. Botrytis affected newly potted plugs and

oedema affected finished and overwintered stock. All other diseases affected all

production stages from mature plugs to finished product. Comments regarding the


success of treatments have been recorded against each, and in some cases could

not be given as the results were yet to be seen. A number of growers did not apply

treatments, but discarded crops.

Table 7. Pests found on Cordyline and the control measures used by respondents.

Pest No. growers affected

Value of crop affected (£)

Control measures Were these measures

successful?

Mealybug 4 >109,000

Decis & CalypsoDursban WGCalypsoGazelle

Good

Thrips 3 >11,000

Amblyseius cucumerisConserveCalypsoNicotine 40% shredsDynamec

Good

Slugs 9 Not provided

Slug pelletsNemaslugCroptex FungexCuprokyltFerramol

Good

Snails 10 >12,000

Slug pelletsNemaslugCroptex FungexCuprokyltFerramolMetaldehyde

Good

Aphid 5 >1,092,888

ChessAphoxCalypsoToppel 100 ECSpruzitAphidius colemaniAphidoletesAgri-50

Good

2-spotted spider mite*

19 Not provided

Apollo 50 SCDynamecFloramite 240 SCSB Plant InvigoratorGyroTalstarMajestikMasaiOberon*Spraying oil Phytoseiulus persimilisAmblyseius californicus

Good

Vine weevil 1 2,000 Cyren

Nematodes Moderate

*NB. Oberon may cause growing point damage in Cordyline.


Table 8. Diseases and disorders found on Cordyline and the control measures used.

Disease / disorder

No. growers affected

Affected crop value

(£)


successful?

Leaf spots (yellow) 19 119,437

AmistarRemove affected leavesPot on

Good

OctaveLiquid feedFungal programme

Moderate

AmistarOctave Systhane 20 EW Croptex FungexBumper 250 EC

Poor

Leaf spots (other) 8 12,250

OctaveAvoid water splash Good

OctaveFeeding Poor

OctaveAmistar Unsure

Tip burn 10 1,055,600

Water managementCalcium in feed / foliar sprays.Site selection (fluoride level) Temperature control

Good

Liquid feedFrost protection Moderate

Control humidity Poor

Octave Amistar Unsure

Stem / crown rot 11 19,425

Curve Rovral WGSubdueAliette 80 WG

Good

Aliette 80 WG Moderate

SubdueProplantAliette 80 WGDry plants outSpace Delsene 50 Flo (not approved for use on ornamentals)Amistar

Poor

Avoid wet foliageRovral WGAmistar

Unsure

Root rot 9 28,564

Discard plants, stop production Good

Aliette 80 WGSubdueDry out growing media

Moderate

Careful, low level watering Unsure

Oedema 3 50,000 Maintain temperature > 6 0CGrow under glass Moderate

Botrytis 1 5,000 Fungicide (sprayed too late) Poor


Phormium

Growers provided details of the major Phormium varieties they grow (Table 9) and

their provenance (Table 10). Where growers had sourced the same variety from

more than one producer the variety was only counted once. Where a grower had

sourced more than one product line from a supplier, each was included individually.

A total of thirty six growers responded.

Table 9. Phormium varieties grown by the respondents.

Variety No. growers Variety No. of

growers

‘Yellow Wave' 23 ‘Rainbow Maiden' 4

tenax 19 ‘Duet' 3

tenax purpureum group 18 ‘Margaret Jones' 3

‘Bronze Baby' 15 ‘Amazing Red' 2

‘Sundowner' 15 ‘Dark Avocado' 2

‘Jester' 15 ‘Rainbow Chief' 22

cookianum subsp. hookeri 'Cream

Delight' 13 ‘Red Sensation' 2

cookianum subsp. hookeri

'Tricolor' 12 ‘Black in Black 1

‘Apricot Queen' 11 ‘Black Velvet 1

‘Evening Glow' 9 ‘Crimson Devil 1

‘Pink Panther' 8 ‘Dazzler' 1

‘Alison Blackman' 7 ‘Glowing Embers' 1

‘Pink Stripe' 7 ‘Golden Alison' 1

cookianum ‘Flamingo' 6 ‘Maori Maiden' 1

‘Gold Ray' 6 ‘Maori Sunrise' 1

‘Rainbow Queen' 7 ‘Rainbow Surprise' 1

‘Platt's Black' 5 ‘Surfer' 1

‘Rainbow Sunrise' 6 tenax 'All Black' 1

tenax 'Variegatum' 5 tenax 'Veitchianum' 1

‘Black Adder' 4 ‘Sunset' 1

‘Gold Sword' 4 ‘Merlot' 1

‘Maori Queen' 4 ‘Peach Melba' 1


Where the UK was stated as the country of origin plants may have been produced by

tissue culture abroad, grown on in plugs in the UK and then further distributed as UK-

produced product.

Table 10. Country of origin of Phormium grown by the respondents.

Country of origin No. growers Country of origin No. growers

UK 28 South Africa 2

France 7 Africa 1

Ireland 4 Holland 1

New Zealand 3 Italy 1

Growers provided details of the companies they sourced their Phormium stock from

(Table 11). Four nurseries did not provide specific supplier information, either

leaving the space blank or recording ‘various’. A total of 32 different suppliers were

listed by growers, who supplied five different categories of product. 53 growers

propagated their own Phormium.

Table 11. Categories of Phormium suppliers.

Supplier category No. suppliers

Seed suppliers 2

Micro-propagators / plug producers 10

Liner producers 14

Suppliers of plants larger than liners 8

Growers reported that a total of 1,238,961 Phormium were grown and 1,113,517 sold

by them on each year. Growers were asked to provide the average number of

Phormium grown and sold by them on their nursery each year. One grower did not

provide this information.


Growers indicated how many Phormium they produce at each production stage

(Table 12). Data was provided by 28 growers.

Table 12. Total number of Phormium either produced or purchased by growers at each

production stage annually.

No. plants

Purchase Produce

Plug 57,300 530,000

Liner 153,875 562,800

1-3 L 42,340 246,380

4-5 L 2,200 20,700

> 5L 2,450 44,100

Growers were asked to indicate the pests and diseases observed on their Phormium

crop and the success of any control measures used. Level of success was graded

into ‘Good’, ‘Moderate’ and ‘Poor’, and some measures fell into multiple categories

as growers had mixed success. Three Phormium growers did not experience any

pest problems on their crops. Mealybugs affected crops from the liner stage to the

finished plant; there was no data for aphids. Other pests recorded affected all

stages. The combination of Talstar 80 Flo + Majestik in December, Masai + Apollo

50 EC in late March and Floramite 240 EC + Oberon in summer was found to be

successful by one grower. Croptex Fungex and Cuprokylt have approvals for use as

fungicides, however growers reported in the survey that they were being used

against slugs and snails.


Table 13. Pests found on Phormium and the control measures used by respondents.Pest No.

growersValue of

crop affected (£)


successful?

Mealybug 19 253,820

Temik 10G (no longer approved)Gazelle ChessIntercept 70 WGImidasect 5 GRDursban WGSpraying oil

Good

Gazelle ChessIntercept 70 WGSB Plant InvigoratorGyroDecisCalypsoExemptor

Moderate

Cryptolaemus montrouzieriDecis protechDimethoate 40

Poor

Thrips 4 No data

Nicotine 40% shredsConserveDynamecAmblyseius cucumeris

Good

Parapet Poor

Slugs 15 74,805

FerramolCroptex FungexNemaslugMetaldehyde

Good

Snails 16 85,403

FerramolCroptex FungexNemaslugSlug bait

Good

Aphid 1 No dataCalypsoAgri-50Aphox

Good

Two-spotted spider mite 20 306,785

Apollo 50 SCGyroTorqAmblyseius californicusPhytoseiulus persimilisDynamecFloramite 240 SCOberonMajestikMasai

Good


Growers were asked to report the diseases or disorders observed on their Phormium

crop and the success of any control measures used (Table 14). Thirteen Phormium

growers did not experience disease problems with their crop. Responses indicated

that all diseases listed had affected all crop stages. A spray programme including

Amistar 80 WG, Systhane 20 EW, Signum and Octave was found to be successful

against general leaf spots. Leaf spots can extend from the base of the leaf into the

crown. Two growers commented that tip burn affects Phormium ‘Alison Blackman’

and that frost protection can help for this specific variety. Many growers did not apply

treatments.

Table 14. Diseases and disorders found on Phormium and the control measures used.

Disease / disorder

No. growers

Value of crop

affected (£)

Control measures used (chemical or

other)

Were these measures

successful?

Leaf spots (yellow) 5 3,375

Systhane 20EWAmistar 80 WGOctave

Good

Leaf spots – other 6 60,000

Octave Bravo 500Bavistin (no longer approved)AmistarSysthane 20EWSignum Space plants

Good

Octave Poor

Tip burn 6 19,750No successful treatment

Stem / crown rot 9 85,300

Rovral WGSubdueAliette 80 WGOctaveDon’t overwaterDiscard

Good

Pot less deep Moderate

Root rot 11 137234

SubdueAliette 80 WG Good

Bio Fungus WP Moderate

CulturalChanged potting mixPotted les firmly

Unsure


Cultural considerations

Growers provided details relating to the quality of the irrigation water used on their

nursery with reference to their Cordyline and Phormium crops (Table 15). Twenty

growers had their irrigation water analysed regularly. Only eight knew the level of

fluoride found in their irrigation water, as this is not generally included in standard

water analyses. Further information was gathered that indicated that three of the

water authorities servicing the respondents fluoridate the water they provide to some

areas, but none of the respondents were located within these areas (Table 16).

Table 15. Details of irrigation water analysis frequency.

How often do you have your water analysed? No. of growers

Not grown 7

No response 5

Never 14

Occasionally 2

Every 2-3 yr 2

Annually 6

Every 6 months 7

Every 3 months 1


Table 16. Details of fluoridation measures taken by the water authorities servicing respondents.

Which authority supplies your water? No. growers

Is fluoride added to your irrigation water by your supply authority?

Borehole 6 N/A

Anglian Water 4

Anglian Water add fluoride in some areas, but the nurseries that responded were not located in a fluoridation zone. There is a postcode search on their website which provides this information.

Southern Water 5 No fluoride is added to water supplies

Severn Trent Water 3

Water is added to 45% of the area covered by Severn Trent Water, but the nurseries that responded were not located in fluoridation zones.

Wessex Water 3 No fluoride is added to water supplies

South West Water 2 No fluoride is added to water supplies

Thames Water 2 No fluoride is added to water supplies

United Utilities 2

United Utilities add fluoride in 3 areas, but the nurseries that responded were not located in fluoridation zones. There is a postcode search on their website which provides this information.

Yorkshire Water 2 No fluoride is added to water supplies

Portsmouth Water 2 No fluoride is added to water supplies

Reservoir water 1 N/A

Three Valleys Water 1 No fluoride is added to water supplies

Welsh Water 2 No fluoride is added to water supplies

Growers gave details of the irrigation system used for their Cordyline and Phormium

crops, and the majority used overhead irrigation (Table 17).

Table 17. Irrigation systems used by respondents (%**).

Growers (%**)Overhead Drip Capillary matting Efford sand bed* Low level

(seep)

Cordyline 100 12 9 12 3

Phormium 94 11 6 11 0

*Drained bed sub-irrigated via header tank or similar (e.g. sand-bed irrigated by lay-flat tube). **Percentages are based on 34 Cordyline growers and 36 Phormium growers.


Growers provided details of the nutrient products applied to their Cordyline and

Phormium crops. As nursery stock growers, the majority used controlled release

fertilisers (CRFs) (Table 18).

Table 18. Nutrient products used by respondents (%*).

Growers (%*)

Base fertilisers 47

Controlled Release Fertilisers 83

Liquid feed 39

Supplementary feed 22

Compost tea 6

*Percentages are based on 36 growers.

The majority of growers provided protection to their Cordyline and Phormium (Table

19).

Table 19. Protection provided to Cordyline and Phormium crops.

Growers (%*)

Cordyline Phormium

Glass 68 50

Polytunnel (unvented) 44 39

Polytunnel (vented) 44 44

Growth room 3 3

None 6 8

*Percentages are based on 34 Cordyline growers and 36 Phormium growers.


Growers were asked if they had any preferences or comments to make related to any

future Cordyline or Phormium crop research. The comments made are quoted

below. Twenty six growers were interested in participating further in this project.

“The main problem is the virus-like leaf markings“.

“Good study“.

“Watering levels, particularly in Cordyline are critical, especially during the

winter. Planting / potting depth of Phormium is also important. These should

be considered in future research“.

“The disease I think we get is Glomerella. It is not much of a problem in

summer, but can be bad overwinter when the foliage is damp, despite sub-

irrigation. Spider mite is a problem and Phytoseiulus does not spread out

well in spiky crops“.

“We have experienced poor rooting establishment under glass. 3 L plants

grown outside one year resulted in well rooted plants. This was attributed to

wind blow inducing formation of 'prop' roots. Work is needed on Phormium

mealybug biocontrol“.

“Would like to know why P. 'Alison Blackman' is so badly affected by tip burn

in the late autumn (I'm sure it's nutritional). Is a disease responsible for the

brown/black circular spots in Cordyline? Any particular nutritional 'design'

needed for a good product. Growing media specification bespoke for

Cordyline and Phormium attached“.

“Phormium are a major crop with us with a value up to £50,000!! “

“Don't do this research - spend money on Phytophthora ramorum“.

“Problems with Cordyline crown rot are the main issue where there is a need

for research. Leaf spots can be controlled with a successful spray program.

With crown rot cultural issues such as watering, compost, ventilation and

general husbandry are all the main issues, along with the source of material“.


“We would be interested in: compost recommendations, potting timings for

spring sales of saleable crops, minimum winter temperatures“.

“Largest problem on cordylines are tip burn, basal stem rots and spots on

australis. Problem with Phormium is mealybug. Looking at using compost

tea in the hope they will prevent stem rots and unstable plants“.

“I expect most problems are due to cultural aspects of production e.g.

Cordylines only have foliar/root problems in older crops, which should have

been potted or shipped out earlier. We have had problems with small water

snails on Cordyline ‘Red Star’. Cordyline ‘Sundance’ had been dropped from

our range for several reasons. ‘Phormium’ do tend to get root death over

winter, whether the crop is run wet or dry. Single colour varieties perform

better than variegated, with fewer problems“.

“Phormiums are not really a problem other than red spider. Cordyline leaf

spot or blotch is a real problem, particularly on green australis“.

“The problem with Cordylines has become more of a problem each year, to

the point where this year's crop has been destroyed“.

“Main problem - virus-like leaf markings“.


Case study results

Data for the case studies was collected from eight nurseries, all of which grew both

Cordyline and Phormium.

Humidity

Growers provided protection to their crops to allow more control of irrigation in wet

weather, thereby reducing humidity around plants as well as within the growing

media. Details of the space provided to plants was stated (Table 20), and this

depended on various factors including:

Some growers only spaced plants when larger than 5 L or not sold; one

grower used a spacing of 10 cm for 12 L pots of both Cordyline and

Phormium

Sale cycle. Phormium on a short sale cycle were kept pot thick and those on

a long sale cycle were kept with 5 cm spacing.

Habit: Phormium with an upright habit were given little spacing but those with

an arching habit were given more space.

Table 20. Plant spacings used by growers (cm).

Plug Liner 1-3 L > 5 L

Cordyline Initial spacing

Trays Trays 0-25 40-100

Final spacing


Phormium Initial spacing


Final spacing


Measures were also taken to ensure adequate air movement around plants. Those

grown under cover were grown under ventilated glasshouses or polytunnels where

doors and side vents were kept open to increase air movement. Some glasshouses

had fans and their usage ranged from being on all the time to providing additional air

movement as necessary; two growers made use of fans during cold weather when


the vents were closed to provide air movement. Gravel was also used as a base to

improve drainage and increase air movement, particularly in larger pots.

Production techniques

Various production techniques were used:

Cordyline australis 'Red Star' and 'Sundance' were purchased as plugs and

potted into 1 L.

Phormium plugs were potted to 1 L then sold; liners to 3 L then sold; 3 L to

7.5 L then sold

Machine potted into 3 L, set down, cleaned once, labelled.

Cordylines were bought in as plugs (C. ‘Red Star. and C. australis) and liners

(C. ‘Torbay Dazzler’, C. ‘Southern Splendour’) and grown on into 3 L plants

and sold.

Both Cordyline and Phormium were generally planted to a depth of 0.2 to 1.0 cm,

however there was some variation:

Cordyline in 30 L pots were planted 15-30 cm below the surface to stabilise

them and encourage rooting from the stem, thereby avoiding ‘wobble’ or

‘rocking’. Rocking was reported by one grower to affect 5-10% of the crop.

One grower found that this condition did not seem to affect C. ‘Torbay

Dazzler’. Cordyline plugs were also planted deeper to prevent rock (there are

implications with this encouraging crown rot). It is critical that the growing

point is not buried.

10 L Phormium were not planted deeper than the original 3L pot to prevent

the growing point from being lost.

Planting to slightly below the crown to avoid rock for both Cordyline and

Phormium.

Liners and plugs were carried in trays, and larger plants were generally handled by

the pot. Potting was carried out by machine with plants held by the root ball, except

for those in 30 L pots which were hand potted. However, some growers did allow

established 3 L pots to be handled by the tops. Less handling problems were

experienced with Phormiums than Cordylines, however they were still predominately

handled by the pot.


A particular issue had been noticed with Cordyline ‘Torbay Dazzler’. It was

suspected that handling by the tops caused damage to the leaf margins of young

plants, seen as browning of the leaf margins in older plants and they were therefore

handled by the pot only.

Protection

Cordyline and Phormium were grown under protection to increase growth, thereby

reducing production time, and under glass in preference to plastic.

Two nurseries did not provide any heating to the crop, although one of these did heat

the work station within the glasshouse. Four growers used gas, three used oil and

one used both gas and oil in different areas. One grower provided under floor heating

to 160C in the propagation area and frost protection to 20C for the rest of the

glasshouse. No fume-related problems to the crop were noted, even though four

growers vented their boilers inside. Heating costs were an issue noted by three

growers, with one standing plants pot thick during the winter to save space and retain

heat.

Irrigation

For both Phormium and Cordyline the predominant irrigation systems used were

overhead sprinklers (eight growers) and Efford sand beds (two growers) with some

supplementary hand watering (three growers). The overhead irrigation systems used

pin jet nozzles, anvil nozzles, rotoframe sprinklers and micronozzles. Irrigation

systems were mainly installed within the last 5 years, although three were over ten

years old. Mains water was the major water source used (Table 21). Three of the

eight nurseries had tested the performance of their irrigation system (for example as

described in HDC Factsheet 16/05). Typical corrective action taken was to adjust the

layout of plants to avoid dry spots.

Table 21. Water sources used by growers.

Borehole Reservoir Mains Roofrun-off

Bedrun-off

Propagation area

1 0 3 1 0

Other protected

3 1 5 2 0

Outside 2 0 0 0 0


Five nurseries, those that used borehole, run-off and reservoir water (one exception)

had systems in place to clean their water:

Aeration to remove iron

Mains acidified with nitric acid, and reservoir water chlorinated to 5 ppm. 3

stage filtration:

o vortex filter (grit and sand)

o chlorination

o high pressure sand filter removing particles about 100 μm

Mesh filter

Ozone and stored in covered tanks

In-line filter from tank to pump

Growers used various techniques to decide when to apply irrigation. All nurseries

manually checked pots and used this information in conjunction with weather

conditions and forecasts. A computer controlled system was also used by one

nursery to apply water little and often early in the morning.

Growers ran predominately dry regimes. Cordyline were kept dry, and more so

during the autumn and winter. Phormium were kept slightly wetter than Cordyline;

two nurseries watered Phormium heavily at first and then allowed them to dry back.

Water regulation was also used to combat spider mite with heavier applications

during hot summer conditions.

In general, little liverwort was found on these nurseries. Infestations tended to be

localised, for example due to a leaky roof, unlevel beds where water collected and by

the doors in winter where moisture was able to dampen growing media. A high

standard of nursery hygiene was maintained with beds and surroundings cleaned

with Jet 5 between batches. A mix of Fungex and Majestik was used after potting on

one nursery, but the effect of this was not clear.

Various different bed constructions were in use (Table 22). Improved drainage

through bed construction would help to reduce root and crown diseases and also

liverwort infestation.


Table 22. Bed construction.

Bed construction No. growers

Sandbed 1

Efford sandbed with growtech cover 1

Capillary matting over polystyrene (benches) 1

Mypex over gravel/slate waste 2

Mypex over polythene, on a slope 1

Gravel 1

Mypex over soil 3

Growing media

A range of ingredients were used in growing media (Table 23) with growers typically

using two to three grades of peat to obtain the required texture. Consideration was

being given to including approximately 15% PAS 100 certified green compost in the

future by some growers. Mulches used included one grower using bark with iron

sulphate to feed plants and this was also thought to help combat moss and liverwort

growth.

Table 23. Growing media components used for Cordyline and Phormium crops.

No. growers %

Bark 6 10-50%

Humic compost 1 10

Perlite 1 10

Coir 1 40

Peat 8 50-85%

Woodfibre (Toresa, Kokos)

2 20-30%

Wetter 2 -

Mulch (bark, coir) 2 -

Five of the growers routinely had their growing media analysed, and four retained

samples of used growing media; growing media producers (Treff and Scotts) also

kept samples. pH ranged between 4.5 and 6.5. Some growers incorporated

pesticides such as Intercept 70 WG (1 grower), ViNil (1 grower) and Exemptor (1 © 2009 Agriculture and Horticulture Development Board 40

grower). The air filled porosity of growing media was tested by two growers (15 %

and 18-25%) and particle analysis was not typically carried out.

6 Nutrition

Table 24. Nutrients applied to Cordyline and Phormium crops.

Product Formulation Quantity

Base fertiliser

PG-mix 15:10:20 0.5 to 1 kg/m3

Micromax (trace elements) 16-18 months 0.25 kg/m3

Treff Base Fertiliser (TBF) High N 17:10:14 1 kg/m3

Scotts Osmocote Start 6 weeks 12:11:17 + MgO + trace elements

Vitafeed 1:1:1*** 19:19:19 + trace elements

1 g/L at 1%

Controlled release fertiliser (CRF)

Osmocote Exact std prill size12-14 month 17:10:10 3 kg/m3

Sinclair Sincrocell 10-12 months 14:08:13 4 kg/m3

Osmocote 12-14 month 17:10:10 3 to 3.5 kg/m3

Osmocote 3-4 month* 18:10:11 + 2MgO + trace elements

plug

Osmocote pro 12-14 month 17:10:10 3.5 kg/m3

Osmocote Standard 8-9 months (1-2 L mix) 15:09:11 2 to 4.5 kg/m3

Liquid feed

Peters Excel (Cordyline australis)*** 18:10:18 + 2MgO 1 g/L at 1%

Peters professional** 1:1:1

Spot feed

Other

Lime 2.5 kg/m3

Wetter 0.4 L/m3

Nitrochalk 0.2 kg/m3

Fritted trace elements 255 0.3 kg/m3

*added to 3L pots before potting on to ensure the core has enough nutrients to push roots out. **throughout the growing season. ***weekly.

Growers provided details of the fertilisers applied to their Cordyline and Phormium

crops (Table 24). Most growers used a base fertiliser with controlled release fertiliser


(CRF). Two growers applied BioFungus Instant to their crop. Three growers

routinely applied compost tea and another was about to start (Table 25).

Table 25. Details of compost tea systems in use.

Product Compost Tea

Supplier Fargro and Van Lersel biezenmortel Tilburg NL.

Brewing method Xtractor

Application regime Typically applied via irrigation lines and knapsack sprayers at approximately 2-weekly intervals.

Other relevant information One grower applied Maxicrop along with Compost Tea

Pests, diseases, disorders and quality

Growers provided details of pests, diseases, disorders and quality issues found

experienced with Cordyline and Phormium crops.

Mealybug

Two growers had found mealybug on Cordyline, treating it with Conserve and

Calypso at the recommended rate when first seen. Imidasect 5 GR and Exemptor

were used at potting by another grower to prevent infestation.

Mealybug was one of the major pest problems of Phormium (Figure 2) as it is difficult

to control (Jones, 2008). It was found more often on older plants, and on the P.

tenax, P. ‘Maori Maiden’ (a weaker variety) and P. ‘Platt’s Black’. It was often

brought into the nursery on the crop and numbers built up in the autumn. Control

measures used were Dimethoate 40, Chess (at the higher rate under SOLA

2834/08), Gazelle, Gyro, Decis, Calypso with applications made when the mealybug

was first seen and then 2-3 times per season. Growing media-incorporated products

Exemptor (280 g/m3) and Intercept 70WG were used at potting for both liners and

final pots by three of the growers. One grower also washed down with Gazelle.


Figure 2 Phormium infested with mealybug (Dan Drakes, 2009)

Thrips

One grower had experienced problems with thrips on Cordyline, but none were

reported on Phormium. The control measure used was Conserve applied at the

recommended rate when present during the spring and summer.

Slugs

Three growers had experienced slug problems on all varieties of Cordyline, and one

had a particular problem on small plants of C. ‘Red Star’. Regular treatments of

Ferramol, metaldehyde pellets and Nemaslug were made. Croptex Fungex

(approved only as a fungicide) copper fungicide was also used (2.5 ml/L) to remove

slugs from foliage.


All growers except one had problems with two-spotted mite and for some this was a

major pest of both Cordyline and Phormium. Susceptibility was not considered to be

varietal, although one grower tended to have more problems on C. a. ‘Torbay

Dazzler’, and for one grower severity of infestation was dependant on time of year

and plant condition. Varieties of Phormium affected were P. Pink Stripe, P. Yellow

Wave’, P cookianum ‘Flamingo’, P. ‘Maori Maiden’, P. ‘Maori Queen’, P. ‘Maori

Sunrise’, P. ‘Sunset’ and P. ‘Golden Ray’

Chemical control measures used were Floramite 240 SC, Gyro, Dynamec, Apollo 50

SC, Masai, Majestik and regular applications of SB Plant Invigorator. Fogging with

Dynamec and Apollo 50 SC had been used but as it is difficult to penetrate the leaf

structure this application method was less successful than a heavy wet spray.

Applications of Dynamec prior to plants leaving the nursery were used to prevent © 2009 Agriculture and Horticulture Development Board 43

carrying two-spotted mites to the customer. Biological controls were used with some

success using Phytoseiulus persimilis, Amblyseius californicus and Feltiella

acarisuga, however there are reports of growers having difficulty in adequately

establishing the predators (Buxton, 2009).

Aphids

Three growers had experienced infestations of aphid, on all varieties and growth

stages of Cordyline; no aphids were reported on Phormium. Both chemical (Chess,

Aphox and Spruzit) and biological controls (Aphidoletes aphidimyza and Aphidius

colemani) were used with success. Aphids were not considered a major pest of

Cordyline or Phormium.

Caterpillars

Tortrix caterpillars had been found on both Cordyine and Phormium by two growers.

They were treated using Conserve and Gazelle and also the biological control

Bacillus thuringiensis (Dipel DF).

Sciarid fly larvae

One grower reported sciarid fly larva on Phormium which they treated with

application of large populations of Atheta coriaria from their own breeding colonies

during propagation.

Undiagnosed yellow leaf spots

There is some confusion regarding yellow leaf spots and oedema; laboratories have

attributed some yellow leaf spots to oedema and some growers may have incorrectly

categorised the condition found in their crops.

Yellow leaf spots were found on five of the nurseries, primarily on C. australis and not

on variegated or purple forms, however one grower did report finding them on C.

‘Sunrise’. Two growers reported finding yellow leaf spots on Phormium but

fungicides were not an effective treatment and one grower destroyed affected plants

to remove the threat to the remainder of the crop. These yellow spots seemed to

appear when plants were short of nutrients or otherwise under stress, with incidence

varying each year. Chemical treatments used were Amistar, Systhane 20 EW and


SB Plant Invigorator. Cultural methods such as attention to irrigation, adequate

ventilation and heavy applications nitrogen fertiliser were also used.

Oedema

Yellow spots indicative of oedema (Figure 1) and similar to that found in Eucalyptus,

only affected Cordyline. All cultivars, but notably C. ‘Red Star’, were affected. Seed

raised plants, larger plants and older leaves were all found to have this condition.

Cultural measures such as adequate ventilation, spacing and warmth all helped to

reduce oedema. Control of pest and disease was thought to be beneficial, as did

regular application of SB Plant Invigorator and compost tea. It was reported that

oedema did not kill plants and they could grow on to be healthy. This condition is

reported to appear at certain times of the year when roots are saturated and wet,

often during the transition period between winter and spring, and often growing out of

it during the summer. It has been found more often in younger plants and some

varieties seem more susceptible than others (Jones, 2008).

Other leaf spots

Individual growers reported the following leaf spots:

Brown markings were reported on the leaf edge of medium aged Cordyline leaves

only, not new leaves in one nursery. Herbicide damage and scorch had been

discounted as causes. Plant handling practices were changed, so they were no

longer handled by the tops and this appeared to have solved the problem.

Black lesions at the base of Phormium had been identified as Colletotrichum or

Fusarium. P. ‘Apricot Queen’ and ‘Sundowner’ were affected; on another nursery

Colletotrichum had been confirmed affecting P. ‘Yellow Wave’ and some pink

varieties (Figure 3a). A mix of Delsene 50 Flo (carbendazim, no longer approved for

use on ornamentals) and Bravo 500 had provided some control in both cases.

Pin-prick brown spots on Phormium leaves were controlled using fungicidal

treatments at 14 day intervals throughout the winter, the spray programme including

Octave, Repulse, Subdue and Amistar.


a B

Figure 3(a) Phormium with suspected Colletotrichum leaf spot (England, 2007) (b) Cordyline with tip burn (Gray, 2009).

Tip burn

Tip burn, or leaf tipping (Figure 3b), was more of a problem with Cordyline, but still of

note in Phormium. Purple Cordyline varieties, C. ‘Torbay Dazzler’, C. ‘Sunrise’, C.

Red Star’ and C. ‘Firecracker’ were affected and the condition was considered

varietal by some growers. One grower reported that tip burn had been successfully

eliminated from stocks of C. ‘Red Star’ (along with a range of foliar and root

problems). A reliable form of C. ‘Red Star’, showing no symptoms of tip burn, had

been created using tissue culture techniques, by taking a single initiation from a

single selection and then increasing stock levels, suggesting that a virus may be a

cause. The condition had been put down to calcium deficiency and humidity by other

growers. Although this was a major problem to growers no other control measures

were used.

Leaf bleaching

Two growers reported leaf bleaching. Cordyline ‘Southern Splendour’ had bleaching

to the back of the leaf tips; it was thought that this may develop into tip burn. No

action was taken as the cause was unknown.

Phormium ‘Jester’ had shown a general all-over paleness and bleaching, which may

have been caused by two-spotted spider mite damage at a young age.


Stem / crown rot

Five growers reported stem and crown rot problems in varying degrees in Cordyline.

Over a period of 10 years, one grower had experienced loss of the terminal shoot on

a low percentage of Cordyline liners which had been micro-propagated and grown in

agar. In one nursery this had been reported as Fusarium by the laboratory and the

disease had been controlled using carbendazim (no longer approved). In another

nursery, Pythium and Phytophthora had been confirmed in liners with poor roots.

Another grower had seen this condition in Cordyline ‘Sundance’ and had stopped

growing that variety. Where incidence was small plants were not treated, however

Subdue, Proplant and Aliette 80 WG were all used by other growers; attention to

watering to avoid wet foliage also helped to reduce infection. In Phormium, stem and

root rot was attributed by some growers to over-deep planting, and the solution was

to plant less deeply. Crown rot caused by Colletrotrichum was found on Phormium

plants which had been weakened by red spider mite although Colletotrichum is more

commonly found as a leaf spot pathogen rather than crown rot. Rhizoctonia solani

had been found 7 years ago in the propagation area of one nursery, in plants that

had been divided. This problem had not been found again since using compost tea.

Cultivars affected were Phormium cookianum cvs ‘Evening Glow’, ‘Flamingo’,

‘Jester’, ‘Maori Maiden’, ‘Maori Sunrise’, ‘Pink Stripe’, ‘Sunset’ and ‘Golden Ray’.

Those least affected were P. ‘Sundowner’, ‘Gold Sword’ and ‘Yellow Wave’. Basilex

(2.0 g/m2) and Rovral WG (1.5 ml/m2) were used to control the disease.

Root rot

Violet root rot caused by Helicobasidion purpurea was observed on a small number

of Cordyline, and identified by John Adlam a few years ago. Other root rots were

found on C. ‘Red Star’ and C. ‘Sundance’, and young plants in general. Some

growers thought that certain varieties were particularly susceptible.

Phormium suffered from root rots during the winter when they had been kept too dry

for too long and then watered; maintaining damper growing media at all times

allowed some growers to avoid this problem.


Cordyline 'wobble' or ‘rock’

This was a major problem affecting around 5% of one grower’s crop. It occurred in

C. ‘Torbay Dazzler’, C. ‘Red Star’ and C. ‘Sundance’, and plants were unstable, not

standing firmly upright. Historically, this condition had been attributed to the material

around Elle Plugs being too dense for plants to root through, however this issue had

since been addressed by the manufacturer and the condition still occured. One

grower had observed that Cordyline root downwards first, then produce lateral roots

which stabilise the plant. Other factors thought to contribute were over-wet growing

media, lack of roots, top heavy plants and roots dying back in winter. Solutions used

were to leave growing media bone dry and plant larger plants (30 L) deeply to avoid

this condition. Some growers had stopped producing affected varieties. Other steps

taken by growers were to grow Cordyline outside to allow wind rock to encourage

plants to produce more roots to add stability.

Other problems affecting Cordyline and Phormium

Collapse had been observed in C. ‘Sunrise’ plants following a period where the

crop had been maintained dry, almost to wilting point and then watered.

Subsequent leaf spotting was suspected to be Fusarium although this was not

confirmed.

P. ‘Alison Blackman’ was considered less robust than some varieties and

suffered from several conditions, including collar damage (due to frost forming at

the top of the growing media), root damage (this was less of a problem if plants

were potted later when more vigorous) and tip damage (due to cold

temperatures).

The relatively lax P. cookeriana cultivars such as ‘Cream Delight’ and P. ‘Pink

Stripe’ developed bruising (Figure 4a) and holes in leaves where they bend over

(found in batches from tissue culture only). This condition occurred more often

during winter and at one nursery. More upright varieties such as P. tenax were

less affected.

Botrytis had been found in new Cordyline plugs and was successfully treated with

fungicide.

A concertina effect (Figure 4b) was noted on some Phormium leaves, but no

action was taken as the cause was not established.


a b

Figure 4 Phormium with (a) bruising (b) crinkly leaves (England, 2007).

Some growers had spray programmes in place to minimise incidence of pest and

disease and weeds (Table 26) where possible:

Protective Delsene 50 Flo (no longer approved for use on ornamentals) and

mixed with Bravo 500, and possibly Octave in autumn (Phormium).

Compost tea plus maxicrop (seaweed) is applied at regular 14 (outside crops)

and 7 (protected crops) day intervals (Cordyline and Phormiium).

Standon Fullstop drench (after transplant), Amistar (one week post transplant),

Plover (four weeks later) and Systhane 20EW (four weeks after transplant)

(Cordyline and Phormiium).

Slug and snail control regularly applied through high rainfall and wet summers.

Octave, Bravo 500 / Repulse, Rovral WG, Fungex Croptex / Majestic mix

alternated (against Cordyline and Phormium).

Plant samples had been analysed for disease by growers, with Pythium,

Phytophthora and Fusarium identified on Cordyline, and Colletotrichum and

Phytophthora found on Phormium.


Table 26. Herbicides applied to Cordyline and Phormium.

Herbicide Timing Rate

Ronstar granules After potting (all crops). Label

Jet 5* Bed preparation. Label

Flexidor Applied to Phormium during September / October, after transplant and 6 wks later.

DoubleLabel1 L/ha

Glyphosate Bed preparation, prior to standing down. Label

Hortisept* Bed preparation Label

None (sensitive crop)

* Jet 5 and Hortisept are not herbicides

As in the initial survey, growers were asked to comment on future Cordyline or

Phormium crop research. The comments made by growers are quoted below:

“Poor rooting at the top of the pot in Cordyline may be due to high salt

conductivity in the top layer of compost, and tests on the compost have

shown this to be the case. This may be due to the watering method (sub-

irrigated sand beds) which can give a gradient of moisture in the pot and lead

to heavier rooting at the base. On the positive side, sand beds do give good

drainage and the foliage is very clean. The lack of rooting by the scaffold

roots at the top of the pot is a severe problem for the nursery and they are

considering doing some overhead watering to flush through the excess salts.”

“Yellow spotting (Cordyline)”.

“Tip burn”.

“Mealybug control”.

“Leaf tipping”.

Two-spotted mite (TSM). “As growers we rely on acaricides to control TSM

as it is very difficult to integrate IPM into Phormium crops. Currently there are

no traps to catch them. When damage is seen it is too late to spray

effectively. Early on, top growth is sparse and most of the IPM controls

cannot search for TSM easily and efficiently. Crops are difficult to spray even

when maturing and seemingly offer a better target. Some Phormium cultivars

have what growers term 'umbrella foliage' where the leaf rolls over like the

underside of an umbrella and where the mites can multiply under the hot

succulent leaf. Moderate spells of warm summer weather (viz. the cloudy,

wet 2007/8 summers) lead to very rapid increases in mite populations. The


pest lives on the underside of the foliage and it is extremely difficult to obtain

good coverage using acaricides following rapid growth. Further work is

required into being confident that growers can target the source of the pest

early in the growing season”.

“Oedema requires further study to ascertain the actual temperatures, RH,

water deficit and water logging parameters which can stress these plants”.

Pest and disease analysis report

Eight whole Cordyline plants, with yellow leaf spots, were submitted to FERA's plant

clinic for detailed analysis. A thorough visual examination was performed checking all

parts of the plants including root and stem base health in addition to any leaf spots or

foliar blight. Samples were tested by incubation and isolation for fungal pathogens,

isolation for bacterial pathogens, ELISA for three common viruses and by electron

microscopy (Table 27). If any visual evidence of pest damage was observed,

samples were passed to entomologists for an expert opinion. Transverse sections

were also cut through representative samples and the ultrastructure of the leaves

examined. In addition to this one representative sample was tested using a novel

diagnostic molecular technique called genomics or ‘pyrosequencing’.

Table 27. Summary of test results for Cordyline samples sent to FERA Plant Clinic

CSL Ref Entomology Bacteriology Virology Mycology

20906124 Negative Negative Negative Negative


20906484 Caterpillar Negative Negative Negative

20906486 Red Spider

Mite (found in

2 samples)

Negative Positive Negative


20906488 Negative Negative Positive Negative



Virology Cordyline samples tested negative (by ELISA) for Tomato Spotted Wilt Virus,

Impatiens necrotic spot virus and Cucumber Mosaic Virus, but for samples 20906486

and 20906488 low levels of rod-like virus particles were seen in sections.

Determining the significance of these particles fall outside the scope of this project © 2009 Agriculture and Horticulture Development Board 51

but could warrant further investigation. However, the inconsistency of their presence

and the low levels of reserves do not provide firm evidence of an underlying viral

problem.

BacteriologyNo primary plant pathogenic bacteria were detected.

Mycology Cladosporium was predominantly isolated, in addition to Botrytis and Trichoderma. A

simple pathogenicity test (Table 28) was performed with a representative culture of

Cladosporium and Botrytis. Sporulating agar plugs were placed aseptically onto

sterilised unwounded and wounded detached purple and green leaves with negative

controls.

Table 28. Results of pathogenicity tests.

Un-wounded Wounded

Cladosporium Negative Slight necrosis

Botrytis Slight necrosis Necrotic lesion

Control Negative Slight necrosis

These results indicate that the Cladosporium was not a primary pathogen, supporting

earlier pathogenicity testing previously completed, and in line with the general

perception that this organism is a common saprophyte. Not surprisingly the Botrytis

was able to cause some necrosis especially when the plant had been wounded.

Ultrastructure analysisA number of representative samples of the leaf spot syndrome were sectioned and

examined under a high-power microscope. Swollen cells, below the epidermis,

typical of oedema were observed. Oedema is a physiological problem thought to

occur due to water relations imbalance commonly occurring during periods of high

water availability and high humidity. Oedema occurs when roots take up water faster

than it can be used by the plant or transpired through the leaves. Water pressure

then builds up in the mesophyll or internal cells of the leaf causing them to enlarge

and form tiny swollen blister-like areas. This results in a swelling of these cells

commonly leading to chlorotic leaf spots. Under certain conditions the cells may

burst leading to a necrotic spot. Oedema is most prevalent in the late winter

especially during extended periods of cool, cloudy weather. It is likely to develop © 2009 Agriculture and Horticulture Development Board 52

when the soil is warm and moist and the air is cool and moist. This environment

results in rapid water absorption from the soil and slow water loss from the leaves.

Overwatering, high humidity, and low light intensities are factors that favour the

development of oedema.

Advanced molecular testingSamples were tested by Dr Ian Adam and Rachel Glover of FERA investigating

advanced molecular diagnostic techniques (as part of a Defra-funded project). The

DNA of a representative sample of symptomatic and non-symptomatic Cordyline

leaves was sequenced. By comparison of the sequences produced it was possible

to look at any DNA differences between the two samples and to identify whether any

other organisms were present. No such differences were found. Although not

replicated, this relatively novel technology does support the theory that pest or

disease was not present or implicated.

DiscussionA number of problems have been identified from this study that warrant further

analysis and discussion to try to understand if there are any common measures

taken or husbandry techniques used by growers that exacerbate or provide some

control. In the initial survey growers were asked to quantify the cost of pests and

diseases to their business, but this was not easy and many were unable to provide a

figure.

Pests

Phormium mealybug

The initial survey indicated that Phormium mealybug was not a major problem on

Cordyline, however it did affect 19 Phormium growers with the value of the damage

to crops in excess of £250,000 in total; seven of the nurseries participating in the

case study were affected. The only biological control available (Cryptolaemus

montrouzieri) provided poor control and opinion was mixed regarding the

effectiveness of chemical products with the majority falling into both the ‘good’ and

‘moderate’ categories. Products ranged from ‘soft’ chemicals such as spraying oil

and SB plant invigorator to Temik 10G (no longer approved, aldicarb, carbamate)

and Dursban (chlorpyrifos, organophosphate). Only one grower did not have

mealybug and the pest had been absent from the nursery for a number of years.

Other pest controls applied to the crop by this grower were acaricides, SB Plant


Invigorator, Bacillus thuringiensis (Dipel DF) (against tortrix caterpillar), Ferramol and

Croptex Fungex (against slugs and snails), Atheta coriaria (own colonies, against

sciarid fly larvae); there were no thrips or aphid on the crop.

Slugs and Snails

Slugs and snails did cause problems for growers, affecting Phormium more than

Cordyline, the cost of which was not provided. However, there was a range of

control options available all of which provided good control. The biological control

Nemaslug was used by two growers and proved effective.


No value was registered for damage due to two-spotted spider mite. However, 19

growers reported infestations on Cordyline and 20 on Phormium in the initial survey;

all 8 on Cordyline and 7 on Phormium in the case studies. This was considered to be

a major problem. A wide range of acaricides and biological controls were available

which were considered to provide good control. However, the difficulties facing

growers in controlling this pest were well described by one grower (refer to pages 36

and 52), and there may be difficulty in adequately establishing the biological controls

(refer to page 46). The grower that did not have two-spotted spider mite on his

Phormium did have it on his Cordyline which he treated successfully with Floramite

240 SC (bifenazate). However, Dimethoate 40 (dimethoate, organophosphate),

which has a label recommendation for use against red spider mite in ornamental

plant production was applied to the Phormium aiming to control mealybug.

Aphid

Aphid was only reported on Cordyline, by five growers in the initial survey and three

in the case studies. Of these, three had applied a value to the crop affected. A

range of biological and chemical controls are available, and it was considered that

these provided good control. Aphid was not considered a major problem.

Thrips

Thrips was not a serious problem, affecting three Cordyline and four Phormium

growers in the initial survey and one grower in the case study (on Phormium).

Tortrix caterpillar

Tortrix caterpillar was found on both Cordyline and Phormium by two growers and

was considered less of a problem.


Vine weevil

Vine weevil was a problem on Cordyline for one grower who responded to the initial

survey, but to no growers in the case studies; moderate control was obtained using

Cyren (Chlorpyrifos) and nematodes.

Sciarid fly

Sciarid fly larvae were also a problem for one grower who took part in the case

studies, and these were controlled using rove beetle Atheta coriaria.

Diseases

Yellow leaf spot / oedema

Yellow leaf spot syndrome and oedema are considered together within the

discussion as it is possible that growers refer to this condition by either name as

there is confusion within the industry. Nineteen growers recorded yellow leaf spot on

Cordyline (£119,437), three of which also recorded oedema (an additional £50,000);

five recorded yellow leaf spot on Phormium (£3,375) but no oedema. In the case

studies six growers had this problem on Cordyline and two on Phormium. The

analysis carried out by FERA found red spider mite on two plant samples, low levels

of an unidentified rod-like virus on two samples and secondary fungal pathogens;

however, there was some evidence of oedema affecting a number of samples. A

number of grower comments were received regarding leaf spots (refer to pages 36

and 52).

Two of the nurseries that took part in the case studies and did not have a problem

with yellow leaf spot / oedema were considered further:

Neither provided greater spacing between pots than the other nurseries and

one placed plants pot thick during the winter (oedema often appears in late

winter). Neither of these nurseries used fans, additional venting or other

techniques to improve ventilation.

One applied no heating; the other had propane heating vented outside. Other

growers who did have yellow leaf spot also used propane heating or applied

no heating.

Both nurseries had overhead irrigation systems, supplementing with hand

watering, and they used mains water for their propagation area or smaller


pots, and reservoir or borehole water for larger pots. One (using reservoir

water) had no systems in place to clean their water including filters whilst the

other (using borehole water) used ozone treatment and stored water in

covered tanks. Other growers with similar systems had yellow leaf spot.

Irrigation decisions were based on weather conditions and manual checking,

and both ran ‘dry’ regimes as evidenced by a general lack of liverwort in

common with other growers. Bed construction was mypex over soil on the

ground and capillary matting over polystyrene on benches in one nursery, and

well drained gravel beds in the other.

Growing media formulation for both nurseries was predominately graded peat

with 20% Toresa woodfibre, 10% bark in one nursery and 33% bark in the

other, with pH 4.5 – 5.5 for both. One nursery incorporated Exemptor

(imidacloprid) in the growing media. Other growers used comparable

proportions of bark or woodfibre. A range of nutrients were used by growers,

predominately base fertililiser, CRFs and liquid feed.

Neither used growth stimulants (e.g. Bio Fungus); but one used compost tea

and the other did not.

None of these responses to the questions posed in the case study suggest that these

factors contribute to the lack of yellow leaf spotting and they do not differ greatly from

the other nurseries.

SB Plant Invigorator was used routinely by one grower who treated the whole crop

via the irrigation lines and also soaked all plants in a solution for 1 hour prior to

potting. Although this treatment was considered successful in managing yellow leaf

spot syndrome, both Phormium mealybug and two-spotted mite were ongoing

problems and it was costly.

Other leaf spots

Other leaf spots were also costly to growers, with eight growers registering problems

with Cordyline, and six with Phormium in the initial survey. The total value of the

damage caused to Cordyline and Phormium crops was £72,250. Only one grower

reported that a sample had been analysed and the pathogen had been identified as

Colletotrichum. To minimise leaf spots growers may need to adjust their water

management in terms of application timing and / or method and ensure the cause is

correctly diagnosed by laboratory analysis so that the appropriate control measures

may be applied.


Tip burn

In the initial survey ten growers registered problems with tip burn in Cordyline and six

in Phormium. The total value of the crops affected was £1,075,350. In the case

studies five growers experienced problems with Cordyline and two with Phormium;

none of them applied any treatments as they did not know the cause of the condition,

although one grower suspected calcium deficiency. From the initial survey,

treatments used by other growers included water management, calcium

supplements, foliar feeding, site selection (fluoride level in water) and temperature,

all of which were considered to have a beneficial effect; humidity control does not

appear to have helped.

There is a strong suggestion from the literature that fluoride toxicity may be involved,

with reports that Cordyline and Phormium are sensitive to fluoride. It is not clear,

however, if that includes those varieties grown in the UK, what level (if any) would

produce an adverse effect, and if the nurseries that experience this problem have

particularly high levels of fluoride in their water. General water authority information

suggests that mains water supplied to these nurseries should be below the level that

would cause problems in general (1.0 mg L-1) and levels in river water are well below

that (British Geological Survey, 2005). Bunt (1988) recommended avoiding irrigating

crops with water with greater than 0.25 mg L-1 fluoride. Fluoride levels are not

commonly included in water analyses and this information would be required to

obtain a precise answer. Growing media pH above 6.0 to 6.5 has been

recommended, but nurseries No. 2 and No. 6 have their pH within that range and still

have tip burn. Calcium and / or potassium deficiency may also be involved. This

condition appears to have been eradicated from stock of C. ’Red Star’ using tissue

culture techniques and this route may be worth considering for high throughput

varieties such as C. australis and C. ‘Torbay Dazzler’. A number of growers

commented on tip burn (refer to pages 36 and 52).

‘Wobble’

Growers were not asked specifically about Cordyline 'wobble' or ‘rock’, although

through discussions it was found to be a serious problem to growers. Some growers

considered that planting depth and growing media management play a large part in


controlling this problem. Grower comments were received relating to this issue

pages 36 and 52).

Crown, stem and root rots

Crown, stem and root rots were estimated to cost growers a total of £28,664

(Cordyline) and £222,534 (Phormium) in the initial survey. Pathogens implicated

were Phytophthora, Pythium and Fusarium. In the case studies, four growers

experienced these problems with Cordyline and six with Phormium. Altering planting

depth and changing irrigation practices had helped some growers to combat these

problems. It is well documented that wet growing conditions contribute to proliferation

of the fungal pathogens, predominately oomycetes, that cause these diseases, and

careful management of irrigation regime, drainage and growing media formulation

can help to control them. Grower comments were received relating to this issue

pages 36 and 52).

ConclusionsPests, diseases and disorders or Cordyline and Phormium were investigated through

a literature review, survey of growers, case studies and laboratory analyses. This

report identifies a number of areas which warrant further investigation, aiming to

establish a definitive cause and practical solution to major problems being

experienced in Cordyline and Phormium production: Phormium mealybug, two-

spotted spider mite and the undiagnosed conditions yellow leaf spot syndrome, tip

burn and ‘wobble’.

Further investigation into the control of Phormium mealybug may include further

evaluation of pesticide options currently available, including better and cost effective

use of ‘soft’ chemicals such as SB Plant Invigorator as this product is being used with

some success. Biological controls are limited, but an investigation of wild Phormium

in their native New Zealand could identify natural predators and parasitoids which

could be studied as potential controls for the future.

There are a number of biological controls and acaricides available for two-spotted

mite; growers are making good use of biological controls, however the success rate

is reportedly poor due to difficulties in establishing predators, resulting in a poor

return on their investment.


Yellow leaf spot syndrome appears to be a physiological problem however plant

tissue analysis has indicated presence of an unidentified virus in a small number of

samples. Investigations could involve further analysis to establish if the small sample

investigated in this study is representative of distribution across the industry and aim

to identify the virus. It would be of interest to monitor growing conditions and the

environment when these spots first appear on new plants, for comparison.

Physiological aspects could be investigated using growth cabinet and nursery trials to

establish best practice to prevent occurrence.

Tip burn affects the crops of many growers, and no clear cause has been established

through this survey. Growers do not treat these symptoms as they have no

diagnosis. Further research is required to identify the cause and devise best practice

advice for nurseries to improve crop quality. This could involve nutrient feeding trials,

investigation of fluoride levels in water sources, analysis of plant samples to establish

if a virus is involved, and / or selection and tissue culture of less prone stock of key

varieties.

Further investigation of planting depth, growing media and water management could

provide growers with best practice guidelines to address Cordyline 'wobble' or ‘rock’,

stem, root and collar rots.


References


Appendices

Appendix 1. Initial survey

Cordyline and Phormium: pests, diseases and disorders – initial survey

Section A – General information

1 Contact details.

Your name

Your nursery

Address

Post code

Telephone Mobile Fax

E-mail

Section B - Cordyline

2 Please complete the following table regarding the major Cordyline varieties you grow and their provenance.

Variety Country of origin Main supplier(s)

1

2

3

4


5

3 Volumes of Cordyline on your nursery

a) On average, how many Cordyline do you grow each year?

b) On average, how many Cordyline do you sell each year?

4 At what production stages do you produce and purchase Cordyline? (Please state quantities as appropriate)

Plug Liner 1-3 L 4-5 L > 5L

Produce

Purchase

5 Please complete the following table indicating the pests observed on your Cordyline crop and the success of any control measures used.

Pest Value of crop

affected (£)

Crop stage affected

Control measures used (chemical or

other)

Were these measures

successful?

Mealybug

Thrips

Slugs

Snails

Aphid


Other


6 Please complete the following table indicating any diseases or disorders observed on your Cordyline crop and the success of any control measures used.

Disease / disorder


Crop stage affected

Control measures used (chemical or other)

Were these measures successful?

Leaf spots (yellow)Leaf spots - other

Tip burn

Stem / crown rot

Root rot

Oedema

Other

Section C - Phormium7 Please complete the following table regarding the major Phormium

varieties you grow and their provenance.Variety Country of origin Supplier

1

2

3

4

5


8 Volumes of Phormium on your nursery

a) On average, how many Phormium do you grow each year?

b) On average, how many Phormium do you sell each year?

9 At what production stages do you produce and purchase stock of Phormium? (Please state quantities as appropriate)

Plug Liner 1-3 L 4-5 L > 5L

Produce

Purchase

10 Please complete the following table indicating the pests observed on your Phormium crop and the success of any control measures used.

Pest Value of crop

affected (£)

Crop stage affected

Control measures used

(chemical or other)

Were these measures

successful?

Mealybug

Thrips

Slugs

Snails

Aphid


Other


11 Please complete the following table indicating any diseases or disorders observed on your Phormium crop, and the success of any control measures used.

Disease / disorder


Crop stage affected

Control measures used (chemical or other)

Were these measures successful?

Leaf spots (yellow)Leaf spots - other

Tip burn

Stem / crown rot

Root rot

Oedema

Other

Section D – cultural considerations

12 Please complete the following table concerning the quality of the irrigation water used on your nursery, with particular regard to your Cordyline and Phormium crops.

Do you have your irrigation water analysed?

If yes, how often?

Can you provide a copy of your latest analysis if required?Do you know the level of fluoride in your irrigation water? Is fluoride added to your irrigation water by your supply authority?Which authority supplies your water?


13 Which type of irrigation system(s) do you use to water your Cordyline and Phormium crops? (Please tick boxes as appropriate)

Overhead Drip Capillary matting

Efford sand-bed*

Low level (seep)

Cordyline

Phormium

Any other information

*Drained bed sub-irrigated via header tank or similar (e.g. sand-bed irrigated by lay-flat tube).

14 What type of nutrient products do you apply to your Cordyline and Phormium crops? (Please tick boxes as appropriate)

Base fertilisers

CRFs Liquid feed SupplementaryFeeds

Other

15 What protection are your Cordyline and Phormium crops grown under? (Please tick boxes as appropriate)

Glass Polytunnel Vented polytunnel

Other None

16 Would you be interested in participating further in this project?

Yes No

17 Do you have any preferences or other comments to make related to future Cordyline or Phormium crop research?


Appendix 2. Case study proforma

Cordyline and Phormium: pests, diseases and disorders – initial survey

Section A – General information

Contact details

Your name

Your nursery

Address

Post code

Telephone Mobile Fax

E-mail

Advance information that may be required:

Copy of irrigation and growing media analysis results

Audit details

Auditor Date of survey Signature of Auditor


Section B – Husbandry

1 Humidity: 1.1 Are plants spaced, and if so by how much (cm)? Please state

approximate timing of spacing out and include details of any interim spacing in the box at the bottom. Specify any differences in the production of the pot sizes you produce.

Plug Liner 1-3 L 3-5 L > 5 L

CordylineInitial spacingFinal spacing

PhormiumInitial spacingFinal spacing

Any other specific production techniques used (please state Cordylines / Phormiums)Other notes relating to spacing of crops

1.2 Air movement measures Are any other measures taken to ensure adequate air movement around the plant e.g. venting, fans etc?


2 Planting depth2.1 How deep do you plant your crops?

Plug Liner 1-3 L 3-5 L > 5 L

Cordyline

Phormium

2.2 How do you handle your crops? Describe how plants are handled when moving them e.g. held by the plant, by the pot; machine or hand potted etc.

Cordyline

Phormium

3 Protection: are plants afforded any protection and, if so, throughout the year, over winter etc (and approx. months)?

3.1 Cordyline

Variety Glass Polytunnel (unvented)

Vented polytunnel

Other None

1

2

3

4

5


3.2 Phormium

Variety Glass Polytunnel (unvented)

Vented polytunnel

Other None

1

2

3

4

5

3.3 Overwinter protection: is frost protection applied over winter?

What fuel is used e.g. gas or fuel oil?Is the boiler vented outside or inside the tunnel or glasshouse?Any other heating-related comments?

4 Irrigation4.1 Irrigation system

Overhead Drip Capillary matting

Efford sand-bed

Low level (seep)

Other

Cordyline

Phormium

4.2 Which water sources are used to irrigate your crops?

Borehole Reservoir Mains Roofrun-off

Bedrun-off

Propagation areaOther protected

Outside


4.3 Water quality

Are there any systems in place to clean your water, and if so what? (e.g. slow sand filters, chlorination, UV, reedbeds, settlement tanks, ozonation etc)Do you have your irrigation water analysed and if so, can you provide a copy of your latest water analysis, please?

4.4 Irrigation efficiency: how old is your irrigation system?

Up to 5 yrs 6-10 years 11-15 years Over 15 years

4.5 Application regime – establishing how irrigation is applied, indicating the likelihood of over-application, well-drained, waterlogging etc.

How do you decide when to irrigate? (timer, weather, knocking out, tensiometer to measure substrate moisture etc)

Run a dry or wet regime?

Any liverwort, moss, algae on the top of pots?

Bed construction?


4.6 Irrigation efficiency:Give details of your irrigation system e.g. pin jet, pressure compensated.

Has the performance of your irrigation system been measured, for example as described in HDC Factsheet 16/05*, and if so was any corrective action required taken?

*HDC factsheets 16/05: measuring and improving performance of overhead irrigation for container-grown crops.

5 Growing media5.1 Growing media formulation

Grade %

Bark

Green compost

Grit

Coir

Peat

Woodfibre

Other e.g. wetters, polymers


5.2 Growing media analysis

Do you have your used and / or unused growing media analysed?

Could you provide a copy?

What pH is your growing media buffered to?

Are any pesticides incorporated into your growing media e.g. for vine weevil, mealybug, and if so what?

Do you retain growing media batch samples?

Could you provide a sample if necessary?

Do you know the AFP of your growing media?

Have you carried out any particle analysis of your growing media, and if so, what were the results?

6 Nutrition6.1 What nutrient products do you use?

Product Formulation Quantity Timing of application

Base fertiliser

CRF

Liquid feed

Other


6.2 Do you add any other products to your growing media e.g. growth stimulants?

7 Are any biological products applied e.g. compost tea? If so please provide details.

Product

Supplier

Brewing method

Application regime

Other relevant information


Section C – Pests, diseases, disorders and quality

8 Pests8.1 Cordyline - please give details of your experiences in dealing with the

pests seen e.g. the time of year when they occur, the extent of the problem, any control measures taken (chemical, cultural etc) and how successful they were.

Mealybug

Main varieties affected

Control measures

Formulation

Timing of application Rate

Thrips


Control measures

Formulation


Slug


Control measures

Formulation



Snail


Control measures

Formulation




Control measures

Formulation


Other


Control measures

Formulation


8.2 Phormium - please give details of your experiences in dealing with the pests seen e.g. the time of year when they occur, the extent of the problem, any control measures taken (chemical, cultural etc) and how successful they were.

Mealybug


Control measures

Formulation



Thrips


Control measures

Formulation


Slug


Control measures

Formulation


Snail


Control measures

Formulation




Control measures

Formulation



Other


Control measures

Formulation


9 Diseases and disorders9.1 Cordyline - please give details of your experiences in dealing with the

diseases and disorders seen e.g. the time of year when they occur, the extent of the problem, any control measures taken (chemical, cultural etc) and how successful they were.

Leaf spots (yellow)


Control measures

Formulation

Timing of application

Rate

Leaf spots (Other)


Control measures

Formulation


Rate


Tip burn


Control measures

Formulation


Rate

Stem / crown rot


Control measures

Formulation


Rate

Oedema


Control measures

Formulation


Rate

Other


Control measures

Formulation


Rate


Do you have a spray programme in place, and if so please give details.

9.2 Phormium - please give details of your experiences in dealing with the diseases and disorders seen e.g. the time of year when they occur, the extent of the problem, any control measures taken (chemical, cultural etc) and how successful they were.

Leaf spots (yellow)


Control measures

Formulation


Rate

Leaf spots (other)


Control measures

Formulation


Rate

Tip burn


Control measures

Formulation


Rate

Stem / crown rot



Control measures

Formulation


Rate

Oedema


Control measures

Formulation


Rate

Other


Control measures

Formulation


Rate

Do you have spray programmes in place for these crops, and if so please give details. (indicate any difference for Cordyline and Phormium)?


9.3 Have you had any plants analysed for disease and if so, what was identified e.g. Fusarium spp. Phytophthora spp. Colletotrichum spp. etc

Cordyline

Phormium

10 Give details of any herbicide programme in place for these crops (indicate any difference for Cordyline and Phormium)?

Herbicide Formulation Rate Timing

11 Do you have any preferences or other comments to make related to future Cordyline or Phormium research?


Documents

Project title:€¦ · Web viewNineteen growers recorded yellow leaf spot on Cordyline (£119,437), three of which also recorded oedema (an additional £50,000); five recorded yellow