EDITOR’S COMMENTS BY SEAN MILLER, PAG, INTEGRATED PEST MANAGEMENT AGROLOGIST

Harvest of winter cereals and pulses has begun in some regions of the province. For

more information on the progress of the 2012 crop, consult the Saskatchewan Ministry

of Agriculture’s Weekly Crop Report at: www.agriculture.gov.sk.ca/Crop-Report

At this time of year, it is easy to get caught up in preparations for harvest. Nonetheless,

whether you are a farmer, researcher or agronomist, it is important to continue

monitoring fields whenever possible and to record the latest crop conditions, weather

and pest observations from this season. Making notes on the problems that came up

this year and how they were solved will help us be ready to predict issues before they

arise next time.

If you are applying a crop protection product this time of year, please remember to

follow the pre-harvest interval guidelines. Refer to the crop protection product label or

the product information in the 2012 Guide to Crop Protection

(www.agriculture.gov.sk.ca/Guide_to_Crop_Protection) for more information on a

specific product’s pre-harvest interval.

Pre-harvest glyphosate should not be applied to crops destined for planting seed, as

the germination and vigour levels can be negatively affected.

Crop Production News VOLUME 34 NO. 6

AUGUST 3, 2012

Crop Production News is a bi-weekly publication prepared primarily by provincial

specialists with the Crops and Regional Services branches of the Saskatchewan

Ministry of Agriculture. It is a compilation of articles related to entomology, plant pathology, weed science, soils and

agronomy issues.

Please do not use any of these articles for any other purpose without first asking the

author’s permission.

If you wish to be added to or removed from our mailing list, forward your request by

email to: cpn@gov.sk.ca

IN THIS ISSUE

Aster Yellows on the Increase

This Year ………………………………. 2

Looks Like Another Sclerotinia

Year ……………………………………. 3

Planning Winter Wheat This Fall:

Some Nutrient Tips to Consider ….… 5

Swede Midge and Other Insects

in Canola in 2012 …………………..... 5

Crop Protection Lab News ………….. 7

White Heads in Wheat? ……………... 7

Crop Questions of the Week ……...… 9

ASTER YELLOWS ON THE

INCREASE THIS YEAR BY ALICA OLSON, SUMMER STUDENT, NORTH BATTLEFORD REGIONAL SERVICES BRANCH

If you see plants in your field that look different or

that seem to be growing abnormally, take a closer

look as it may be aster yellows. With the

combination of a wet spring, recent hot weather and

an abundance of leafhoppers earlier on, there has

been an increase in the incidence and the symptoms

of aster yellows in many areas.

Aster yellows is a disease caused by a

pathenogenic micro-organism called a phytoplasma.

The symptoms of the disease depend on the

species of plant. The most obvious symptoms are

the malformed flowers and pods that give the plant

an abnormal appearance (Figure 1). Aster yellows

can affect 300 species of plants in 48 plant families,

including broadleaf crops, vegetables, ornamentals,

weeds and, to a lesser extent, cereal crops. In

Saskatchewan, the crops that we may see

symptoms on include canola, camelina, mustard,

flax, sunflower, alfalfa, potato, carrot, tomato, pea,

wheat and barley. You may also see various weeds

infected with aster yellows, including redroot

pigweed, dandelion, stinkweed, chickweed,

quackgrass, wild mustard, lambsquarters, knotweed

and sowthistle.

The phytoplasma pathogen lives in the phloem

tissue or the sap of infected plants and is transmitted

from plant to plant by leafhoppers. Another source of

the pathogen is the United States where it can be

carried by infected leafhoppers arriving on wind

currents. Leafhoppers acquire the phytoplasma and

transmit it to new plants as they feed. They insert

their needle-like mouth parts into plant tissue, inject

their saliva, then suck up the sap. It is through their

saliva that the aster yellows phytoplasma is

transmitted. Leafhoppers do feed on the plant but

the feeding itself is not considered an economic

threat to the crop; it is the disease transmission that

is a concern.

After feeding on an infected plant, it takes two to

three weeks before the leafhopper becomes

infectious and can pass it on to other plants. The

infectious period will last for the remainder of the

leafhopper’s adult life (one to three months) during

which the infected hopper can move from field to

field spreading aster yellows. Luckily, the

phytoplasma is not transmitted to the overwintering

eggs; however, the pathogen can overwinter in the

root tissue of biennial or perennial crops or weeds,

thereby providing a source of the disease in early

spring.

Once infected, symptom development depends on

the age of the plant. Younger plants show symptoms

within several days, while older plants can take two

to four weeks. Because of the delayed expression of

the disease in plants, symptoms usually appear later

in the season and damage is minimal. In 2007, aster

yellow was more prevalent and some Prairie canola

fields had up to 15 per cent infected plants. Potential

yield loss is hard to determine, as it depends on the

level of infection and how early the plant was

infected; however, research by Agriculture and Agri-

Food Canada in Saskatoon has shown that a 10-

per-cent incidence of infected plants may result in

yield losses of between three and seven per cent.

Symptoms on the plant can vary from completely

abnormal looking plants to more normal looking

plants that have reduced seed set. Some plants can

Figure 1: Aster yellows on canola

Source: Saskatchewan Agriculture

2

look normal but the pods are empty. Unfortunately,

these symptoms do not appear until late in the

season. In most years, fields will only show trace

amounts of this disease (rarely more than five per

cent). Usually, economic loss from aster yellows in

canola is minimal. In canola, the damage usually

looks worse than it actually is, because infected

plants are usually taller than the rest of the crop,

with distinctive symptoms and an erect nature.

Infected canola plants are often discoloured, with

flowers replaced by green leaf-like structures and

pods becoming deformed and bladder-like in

appearance.

We have had reports of aster yellows in fields in

Saskatchewan. This is not surprising, given that

leafhoppers were reported in high numbers this

spring with a higher-than-average infection rate

reported by Agriculture and Agri-Food Canada.

Unfortunately, there is nothing to fix the situation.

There are no products registered to control the

disease itself and no varieties with resistance. Once

the symptoms appear, there is nothing that can be

done to reverse the infection or kill the organism.

Ways to minimize the potential for aster yellow

infection in future years include: seed early, control

perennial weeds in and around susceptible crops,

avoid planting near perennial crops that are known

to be infected, and watch for the presence of leaf

hoppers. Application of an insecticide registered for

use on leafhoppers may be beneficial if populations

are high enough early in the season.

For more information contact your nearest regional

crops specialist or the Agriculture Knowledge Centre

in Moose Jaw at 1-866-457-2377.

LOOKS LIKE ANOTHER

“SCLEROTINIA YEAR” BY FAYE DOKKEN-BOUCHARD, PAG PROVINCIAL SPECIALIST, PLANT DISEASE

Sclerotinia sclerotiorum is a fungus that affects

broadleaf crops. It is favoured by moist conditions,

so, given Saskatchewan’s relatively dry climate, we

do not experience widespread infection every year.

Similar to 2010, it appears that 2012 will be another

“sclerotinia year” thanks to excess rainfall, thick crop

canopies and readily available sources of inoculum.

In 2010, the average incidence of sclerotinia white

mould in canola was 20 per cent (with incidence up

to 93 per cent). In 2011, the provincial average

dropped to 10 per cent but there were still crops with

up to 92 per cent incidence of sclerotinia white

mould reported in the survey, reflecting the potential

difference in any given field compared to the

provincial norm.

Numerous cases of sclerotinia-infected crops have

already been reported throughout much of the

province in 2012, and infestations in canola, lentil,

pea, chickpea, sunflower and various vegetable

crops is possible. Disease surveys will take place in

August but, based on preliminary reports, it is

expected that sclerotina white mould will be severe

in some fields.

In canola, the disease cycle begins with flower petal

infection. Ascospores released by apothecia (Figure

2) infect flower petals, which are easier to penetrate

than other plant parts. The fungus then uses flower

nutrients to grow strong enough to infect other

tissues after petals drop. Fallen petals are

sometimes trapped in the crux of a branch, a moist

spot where infection can occur. Figure 3 shows early

symptoms of sclerotinia developing in the crux of a

canola branch.

In pulses, particularly lentils (Figure 4), infection can

occur through direct contact with mycelium produced

by the sclerotia in the soil. The fungus then spreads

Figure 2: Sclerotinia apothecia

Source: Saskatchewan Agricultue

3

through plant-to-plant contact, which is facilitated by

thick, lodging crops.

Regardless of the method of infection, moisture is

the key to sclerotinia white mould development,

making the disease as difficult to forecast as the

weather. Infections tend to occur below the crop

canopy: a humid, windless microclimate highly

suitable for disease development. Infection of the

plant stem adversely affects nutrient and moisture

flow within the vascular tissue of the plant. This

results in premature death of the plant or reduced

yields. Eventually, sclerotia will form on or inside the

plant and drop into the soil before or during harvest,

and thus are available to cause disease in the

future. Rotation away from susceptible crops is

required to prevent infection; however, this is not

usually an option due to the long life of the resistant

sclerotia (up to five years) and the agronomic

requirement for diversity in our crop rotation

(including broadleaf crops).

In order to control this disease, fungicides need to

be applied early. The most opportune time to apply

fungicide is between 20 to 50 per cent bloom for

canola. The earlier the disease causes infection, the

more time it has to cause damage. Therefore later

infections will cause less damage, making control

less economically beneficial. With pulses, timing is

more difficult, as the start of flowering is the

recommended fungicide target for management of

pulse diseases and sclerotinia doesn’t usually

appear until after the canopy closes. Completion of

flowering and closure of the crop canopy effectively

limits the impact fungicide might have on the

situation, as the product cannot be applied to the

parts of the plant most heavily affected by the

disease. Sclerotinia is a mono-cyclic disease, which

means there is only one disease cycle per season. If

you do not stop it before the disease cycle has

reached the point of producing visible symptoms, it

is too late to control. Economic gains are not

realized if fungicide is applied too late, and there is

no agronomic benefit.

Fungicides are made to protect the plant, not cure

disease. Keep in mind that fungicides’ so-called

systemic effect usually refers to the chemical’s ability

to move into the immediate cell structure of the

plant. The chemicals are not carried through

vascular tissue to reach all parts of the plant;

therefore, their effectiveness is based on contact

with the immediate zone of concern.

For more information on this disease, see the

Saskatchewan Agriculture factsheets Sclerotinia

Infection in Field Crops and Sclerotinia Rot of

Vegetables.

Figure 3: Sclerotinia lesion forming in the crux of a canola

branch

Source: Saskatchewan Agriculture

Figure 4: Sclerotinia white mould growing on lentil pods

Source: Saskatchewan Agriculture

4

PLANNING WINTER WHEAT THIS

FALL: SOME NUTRIENT TIPS TO

CONSIDER BY KEN PANCHUK, PAG, PROVINCIAL SPECIALIST, SOILS

The focus, when establishing winter cereals, is to

seed shallowly into a field of standing stubble at the

correct seeding date. Ideally, winter wheat should be

seeded by the end of August in the northern part of

the province and by the end of the second week of

September in the south. Also, leaving as much

stubble as possible standing after seeding will trap

snow and provide an early insulating blanket as well

as conserving moisture.

Starter phosphate fertilizer with perhaps some

potash blended in assists in achieving healthy plants

for optimizing the winter hardiness going into winter,

as well as improves winter survival.

What are the nitrogen options? A soil test prior to

seeding will indicate the level of nitrogen left from

the previous crop and assist in determining how

much phosphate and potash is needed.

When considering nitrogen options, look at field

conditions too. If it is wetter than normal when you

are seeding winter wheat, you may want to use

ESN, a polycoated urea to minimize nitrogen losses

during the fall and the spring melt. If conditions are

normal, then urea in a side-band or mid-row-band

will work well. Remember not to compromise the

shallow-seeding-depth requirement just to get the

fertilizer banded into the soil.

If winter survival is excellent and moisture conditions

point to potentially high yields, additional urea-

nitrogen can be broadcast in early spring with or

without a urease-inhibiting product, depending on

conditions at the time. Dribble-banding liquid

nitrogen with or without a urease-inhibiting product is

also an option for early spring application.

To discuss these and other agronomic

considerations when planning for winter wheat or

other winter cereals, contact the Agriculture

Knowledge Centre at 1-866-457-2377 or your

nearest regional crops specialist.

SWEDE MIDGE AND OTHER

INSECTS IN CANOLA IN 2012 BY SCOTT HARTLEY, PAG, PROVINCIAL

SPECIALIST, INSECT AND VERTEBRATE PEST

MANAGEMENT

AND

DR. JUDY SOROKA, RESEARCH SCIENTIST,

AGRICULTURE AND AGRI-FOOD CANADA,

SASKATOON

Swede midge larvae have been found in misshapen

canola flowers in fields in the northeast of

Saskatchewan. Canola fields in the Codette,

Nipawin and Carrot River areas surveyed on July 18

to 20 were found to contain swede midge larvae.

Symptoms included aborted flowers or flowers with

petals apparently fused or glued together, and

misshapen, stunted or sometimes missing pods.

This should not be confused with aster yellows (see

article on page 2).

The first suspected specimens of swede midge

larvae in Saskatchewan were collected west of

Nipawin in 2003, but the specimens were not

positively identified and no other larval infestations

were found until now. Canadian Food Inspection

Agency personnel caught small numbers of adult

swede midge in pheromone traps in the

northeastern (Nipawin and Melfort) and east-central

(Yorkton) areas of Saskatchewan in 2007.

Swede midge larval feeding causes swollen, twisted

and distorted plant tissue. Prior to 2012, no

symptoms of swede midge infestations were noted

in Saskatchewan canola. In Ontario, where the pest

was found in 2000, symptoms of damage associated

with swede midge depend on the growth stage of

canola, when feeding occurs and the intensity of

feeding. If larvae attack pre-bolting canola, the

growing point may become necrotic and bolting

might not occur. Damage to a bolting stem may

cause a “palm tree” effect, with a shortened raceme

crowned with a bouquet of pods radiating out from

one point rather than along a typical raceme. After

full flowering, swede midge does not impact canola

5

yields. In the northeast this year, the racemes

appeared normal except that some flowers had

fused petals that did not open. When dissected, the

flowers contained small larvae, with up to 14 found

in one flower (Figure 5). Small, misshapen or

missing pods occasionally were found below the

infested flowers.

The reasons for the outbreak in Saskatchewan in

2012 are not known. Moist conditions in 2011 and

2012 would have been favourable for swede midge

population buildup. In addition the mild winter of

2011-12 may have allowed for better over-wintering

survival of the swede midge.

Native to Eurasia, the swede midge is similar in size

to the wheat midge, with both belonging to the fly

family Cecidomyiidae. However, the swede midge

feeds only on plants in the crucifer (cabbage) family,

and differs from wheat midge in colour, being

creamy yellow rather than orange; swede midge

larvae can “jump” or spring away from contact. In

Ontario, there are four generations of swede midge

a year. Overwintering in the soil as pupae, the first

spring adults appear in mid- to late May. Effective

insecticidal control is difficult because of overlapping

and multiple generations, short adult life span and

the concealed nature of larval feeding.

Other Insect Issues

In all situations of insect infestations it is

important to use registered insecticides if

control is required and to keep in mind pre-

harvest intervals when considering control

options.

Aphid infestations have been reported in several

areas and in a variety of crops including lentil, pea,

canaryseed, wheat, barley and canola. The need for

control will depend on the number of aphids present.

insecticide must be registered for the crop. Refer to

the documents Economic Thresholds of Insect Pests

and the 2012 Guide to Crop Protection, available on

the Saskatchewan Agriculture website, for control

options.

Zebra caterpillars continue to cause damage to

podded canola fields, primarily in the southeast.

Most reports indicate the caterpillars are large and

feeding should soon cease, but if the large larvae

are actively feeding on pods, treatment may be

warranted if it is combined with other insect feeding.

See the Crop Production News July 23 issue for

more information on aphids and zebra caterpillars.

Bertha armyworm larvae are on the increase in

many areas. The final bertha armyworm map of

adult moths is posted on the Saskatchewan

Agriculture website. The map is an indication of risk

based on potential mating adult moths. Actual larval

numbers will be specific to the field. Various colour

versions of bertha larvae, including the typical darker

black types, have been observed. In most cases, the

larvae are now in later and more destructive larval

stages and control may be required. Some

infestations are well above economic thresholds.

Figure 6 shows the remnants of bertha armyworm

larvae on a wheel following insecticide application.

Refer to the

Saskatchewan

Agriculture

publications

Bertha

Armyworm or

Economic

Infestations of

Insect Pests for

recommended

economic

thresholds.

Figure 5: Swede midge in a canola floret

Source: Agriculture and Agri-Food Canada, Saskatoon

Figure 6: Remnants of bertha

armyworm larvae

Source: Saskatchewan Agriculture

6

CROP PROTECTION LAB NEWS BY CECILIA PELUOLA, AAG, SUPERVISOR, CROP PROTECTION LAB

Crop pest issues continue to emerge across the

province, which has been reflected in samples

submitted to the Crop Protection Laboratory over the

last month. Environmental and chemical damage

was diagnosed as well, and the most frequently

submitted samples included wheat, barley, canola,

lentil, pea and flax.

Diseases of cereals and grasses diagnosed in the

last month included smut caused by Ustilago tritici

on wheat and U. bullata on wheat grass. Numerous

wheat samples have been submitted recently

exhibiting white heads. We are in the process of

investigating a number of possible causes: refer to

the White Heads in Wheat article on this page for

further information.

Several barley samples have also been received

with brown glumes (Figure 7). These symptoms can

be associated with fusarium head blight, spot blotch,

and even physical damage such as hail. Lab plating

techniques can be used to differentiate any

pathogens associated with these symptoms.

Diseases diagnosed on oilseed crops such as

canola, flax and sunflower included blackleg

Leptosphaeria sp, alternaria leaf spot, sclerotinia

stem and pod rot and aster yellows.

Diseases diagnosed in peas included root rots (likely

associated with Fusarium spp), ascochyta foot rot,

mycosphaerella blight, leaf spots caused by Septoria

pisi and Ascochyta pisi, and sclerotinia stem rot.

Lentil samples have reflected the moist conditions

and thick crop canopies found in many fields this

season—with evidence of sclerotinia stem rot,

botrytis grey mould, ascochyta blight, anthracnose,

and stemphylium blight in various combinations.

Insect pests identified in the last month included leaf

gall wasp (Neuroterus sp), oak petiole gall wasp

(Andricus quercuspetiolicola), weevils (family

Curculonidae), seed bugs (family Lygaeidae), and

gall mites (Eriophyes sp).

Weed samples identified recently included Parietaria

pensylvanica (Pennsylvania pellitory), Rumex sp

(dock sp), Agrostis scabra (rough hair grass) and

Galium sp (cleavers).

WHITE HEADS IN WHEAT? BY CROPS BRANCH SPECIALISTS

Farmers and agronomists have been reporting

wheat fields with numerous white heads that have

appeared in the last couple of weeks. The Crop

Protection Lab has received many calls and samples

and is in the process of investigating a number of

possibilities.

Fusarium Head Blight and Other Disease Issues

Wheat that survives the seedling blight and root

rotting complex (Cochliobolus sativus and Fusarium

spp) at the seedling stage but succumbs after

heading may suffer from prematurity blight. Infected

plants are often scattered throughout the field. They

are easily pulled from the soil and exhibit poorly

developed and discoloured roots and crowns along

Figure 7: Six-row barley with brown glumes

Source: Saskatchewan Agriculture

7

with white heads that produce few or no kernels

(Figure 8).

Most of the Fusarium species involved in root rots

may also cause fusarium head blight (FHB) if spores

come in contact with the heads, spreading through

rain or wind during anthesis (flowering). Premature

bleaching (Figure 9) will be apparent in one or more

of the spikelets in a head, sometimes including the

rest of the spike above the point of infection. These

spikelets may not produce seed, or result in light,

chalky kernels. Pink or orange Fusarium spores are

sometimes visible on the glumes of infected plants,

particularly when conditions remain wet after

infection.

“Take-all” (Gaeumannomyces graminis) can cause

stunting, reduced tillering, empty white heads and

premature ripening or death. The disease often

occurs in patches and, similar to root rots, plants

with rotten roots are pulled easily from the ground.

Unlike root rots however, fungal growth may be

visible on the lower stem of plants infected with take

all and roots and culms may exhibit a shiny black

appearance.

Barley yellow dwarf infections may cause premature

death of infected plants, which are stunted with

yellow leaves and few tillers. Spikelets may be

sterile on the top and bottom of the spike, which is

also reduced in size.

Aster yellows has been widespread in other crops

this season (see the aster yellows article on page 2).

Wheat is commonly infected with aster yellows but

rarely shows symptoms. Previously reported rare

symptoms include yellowing leaves, shriveled heads

with distorted awns or floral parts that look like

leaves. Many of the reported white heads have been

on green stems with healthy roots and no obvious

disease symptoms (Figure 10). As a precaution,

some samples like this have been submitted for

aster yellows diagnosis. Results will be reported

when available.

Under high disease pressure from leaf spots,

glumes and awns may become spotted. Plants that

have died or ripened prematurely for any reason

may also exhibit sooty moulds which turn the heads

brown or black due to the growth of saprophytic

fungi. By the time any of the above disease issues

appear, control with a fungicide is not beneficial.

Figure 10: White heads with green stems (cause unknown)

Source: Saskatchewan Agriculture

Figure 9: Bleached spikelets caused by FHB

Source: Saskatchewan Agriculture

Figure 8: White head (photo) with stem (inset) that pulled

away easily due to root rot

Source: Saskatchewan Agriculture

8

Insects

There are insects that can cause white heads in

wheat, most commonly the wheat stem maggot

(Meromyza Americana), which is the larva of a fly.

Eggs are laid by the adult fly in the upper part of the

plant and the larva burrows in to consume the

interior parts of the stem. The upper part of the stem

dies and the result is a bleached or white head.

Although the white heads are obvious in a green

field, the actual infestation rate of wheat stem

maggot is usually only about one per cent. To

determine if it is a maggot, pull the wheat head and

stem from the sheath. If the stem pulls out easily, a

maggot is usually the culprit (Figure 10). If the stem

does not detach easily, it is usually indication of

another problem.

Wheat stem sawflies do not generally cause white

heads in wheat. The feeding of a sawfly larva can

result in reduced seed set or shriveled seed but not

mortality of a complete head.

Herbicide Damage

It is very unlikely that herbicide exposure would

result in the production of white heads in cereal

plants without other symptoms of that herbicide also

being apparent. Herbicides in Groups 1, 2, 5, 6, 7, 9,

10, 11, 14 and 27/28 have the potential to produce

bleaching symptoms, but to produce white heads,

exposure to these herbicides would have to occur

very late in the development stages of the plants; in

most cases well beyond the herbicide’s

recommended application window.

Group 4 herbicides can also result in the formation

of white heads, either directly as a result of

application outside of the recommended application

window, or indirectly as an additional stress on a

plant already predisposed to the formation of white

heads as a result of other stresses indicated in this

article. The risk of Group 4 herbicides being an

indirect contributor to the formation of white heads

increases greatly when they are applied outside of

the recommended plant stage.

Environmental Stress

High temperatures along with bright sunlight and hot

winds may cause heat sterility or stress of entire

plants or portions of the head. Heat during filling can

also cause a number of kernel conditions as well.

Plants that were stressed due to excess moisture

earlier in the season may have shallow rooting depth

and be particularly sensitive to heat stress later in

development. On the flip side, low temperatures can

also stress plants and damage immature heads.

Hail damage can also cause white heads when

death occurs above the point of injury. In this case,

wheat heads will be accompanied by signs of

physical damage (broken stems, missing glumes,

etc.).

Unfortunately, no matter what the cause of white

heads in wheat this season, nothing can be done at

this stage to resolve the issue. There may be more

than one factor at play in a given field, and while the

appearance may be alarming, the symptoms likely

appear worse than the actual damage.

CROP QUESTIONS OF THE WEEK BY BRENT FLATEN, PAG, CCA, INTEGRATED PEST MANAGEMENT SPECIALIST, AGRICULTURE KNOWLEDGE CENTRE

The most commonly asked questions this past week

included the much higher than normal incidence of

aster yellows in canola and, in some cases, flax (see

article on page 2), insect pests, crop diseases and

non-pathogenic yellowing of crops.

Many people are noticing yellowing in cereal crops

such as wheat. In most cases, these yellowed

leaves have been turning bronze as they dry down.

These characteristics can be attributed to what we

call physiological leaf spot (non-pathogenic causes),

leaf diseases

such as tan

spot and

septoria

complex, or a

combination

of both.

Figure 11

shows

physiological

leaf yellowing

with no

Figure 11: Physiological leaf spot

Source: Saskatchewan Agriculture

9

apparent disease. Figure 12 shows physiological

leaf yellowing along with leaf disease.

Loose smut is also showing up. Figure 13 shows a

wheat head after wind and rain removed most of the

black loose smut mass. Spores from smutted heads

won’t produce more smutted heads in the same

crop-year, but will infect nearby wheat, the seeds of

which will cause infection next year. Only a systemic

seed treatment that controls the loose smut hidden

inside infected seeds can control the disease.

Inquiries have also been dominated by insect issues

such as aphids in lentils, wheat, canaryseed, canola

and peas. Other canola insects, including

diamondback larvae, bertha armyworms and zebra

caterpillars, have been issues.

A final issue was the raising of Europe’s maximum

residue limit for glyphosate in harvested lentils.

Although this makes pre-harvest glyphosate

possible for lentils bound for Europe, contact your

buyers to make sure they will accept lentils that have

had pre-harvest glyphosate applied.

When applying later-season fungicides and

insecticides, always take into account the pre-

harvest intervals requires so that crops do not

exceed maximum residue limits. Remember that

“pre-harvest” means before the crop is cut (either

swathed or straight-combined). Pre-harvest intervals

do not include the time the crop is in the swath.

The Crop Production News is a publication of

Crops Branch, Saskatchewan Ministry of Agriculture

Telephone: (306) 787-4671

Email: CPN@gov.sk.ca

Figure 13: Loose smut head after wind and rain

Source: Saskatchewan Agriculture

Figure 12: Leaf disease and physiological leaf spot

Source: Saskatchewan Agriculture