Foliar Disease Management in Pulses

What are the tools and how to use them

Sabine Banniza, Crop Development Centre

Steps for disease management decisions

1. Disease identification 2. Assessment of severity of infection 3. Assessment of risk for further spread 4. Identification of short-term management

tools 5. Long-term management strategies

DISEASE IDENTIFICATION

Step 1

Organisms that cause plant diseases

Fungi (spores: 5 – 50 μm)

Bacteria (0.6 – 3.5 μm)

Viruses (17-1000 nm)

Mollicutes (0.3 – 1.0 μm)

Nematodes (250μm – 12mm)

SYMPTOMS CAUSED BY PLANT PATHOGENS

CHLOROSIS

NECROSIS

GALLS & TUMORS

WILTS

SCABS & CANCERS

S. Chatterton

Chickpea ascochyta blight

Lentil anthracnose Lentil stemphylium blight Sclerotinia (L) and Botrytis (R) on lentil

Lentil ascochyta blight Pea ascochyta blight Faba bean ascochyta blight

Chocolate spot of faba bean

Soybean pictures (bottom row in the presentation) from University of Minnesota Extension (copyright protected)

(https://www.extension.umn.edu/agriculture/crop-diseases/soybean)

BUT….

….some of these symptoms can be mixed up with

• Herbicide damage

• Nutrient deficiencies

• Physiological abnormalities

• Environmental damage

Faba bean

Chocolate spot Herbicide or surfactant burn

Soybean

Many (but not all) major diseases

in W-Canada are caused by fungi

PEA LENTIL CHICKPEA FABA BEAN SOYBEAN Ascochyta blight (each crop with its own species) Septoria brown

spot Anthracnose (Anthracnose) Bacterial blight

Botrytis grey mould (Botrytis cinerea) Chocolate spot (Botrytis fabae)

Frog eye leaf spot (Cercospora)

Sclerotinia white mould Stemphylium blight Anthracnose

Aphanomyces root rot Phytophthora stem rot

Pythium & Rhizoctonia root rots Fusarium root rots

Disease identification

• Disease guides: → DFCC – APS compendia

(http://my.apsnet.org/APSStore/Category?Category=Compendium)

• Diagnostic Labs • APPs (?)

ASSESSMENT OF SEVERITY OF INFECTION

Step 2

When to scout • Root rots:

– Seedling stage as root rot is most damaging • Foliar diseases of chickpea:

– throughout the lifecycle for ascochyta blight • Foliar diseases of other pulses:

– Whenever it has rained and/or your canopy has been wet

– Definitely before canopy closure – After canopy closure, particularly for late season

diseases

How to scout • IN the field • Starting at spots with

highest risk – adjacent to a field with

infested crop residue – Spots with high fertility

or high moisture levels

ASSESSMENT OF RISK FOR FURTHER SPREAD

Step 3

SPREAD OF PATHOGENS

BY

Spores (fungi) Sclerotia (asexual melanized fungal cells) Infected plant debris, seed, plants….(all

pathogens to varying degrees)

THROUGH Wind Rain Vectors (insects, animals, YOU, YOUR TRACTOR)

THE DISEASE TRIANGLE

Amount of

disease

Environment:

RAIN

humidity

temperature

Pathogen:

Abundance

virulence

Host:

susceptibility

Symptoms

Infection process

Spore

Germ tube Appressorium

Penetration peg

Incubation period Cell invasion, symptom

development, new spores

Germination & Penetration

Lentil Fungicide Decision Support Systems

Fungicide Decision Support Systems

For chickpea:

http://www.agriculture.gov.sk.ca/Default.aspx?DN=8319f54f-769e-4db5-ba9f-807ad9c60204

(or http://www.agriculture.gov.sk.ca/crops Then click on chickpea production diseases ascochyta blight of chickpea)

IDENTIFICATION OF SHORT-TERM MANAGEMENT TOOLS

Step 4

Short-term management tools

• Fungicide application – Rotate active

ingredients

Fungicides: The more colourful the better CHEMICAL GROUP 3 7 11 44 M3 M5

FUNGICIDE NAME \RESISTANCE RISK med med high low low low

Acapela

Bravo 500, Echo 720

Delaro

Dithane, Kingpin, Manzate, Pencozeb

Elatus

Headline EC

Lance

Lance AG

Priaxor

Proline

Propel, Tilt

Propulse

Quadris

Quash

Quilt

Serenade

Vertisan

Short-term management tools • Fungicide application

– Rotate active ingredients – Timely application before

or within about 24 h after rain

– No fungicide is transported throughout the plant → new growth is unprotected

– Actives will eventually degrade (see pre-harvest interval)

– Efficacy of applications decreases as canopies become denser (late season diseases, aka sclerotinia)

Short-term management tools

• Manage crop canopy – Dense canopy = wet

canopy = higher disease risk

– Weed management • Keep your plants

stress-free & happy (….whatever it takes) – Adequate fertilization

Picture removed because of copyright protection

LONG-TERM MANAGEMENT STRATEGIES

Step 5

#1 Tool: CROP ROTATION • Aphanomyces

infested land: – No pea or lentil for 6

to 8 years • Land free of

Aphanomyces: – 4-year rotation, but

see host range of pathogens

Picture removed because of copyright protection

Many major diseases

in W-Canada are caused by fungi

PEA LENTIL CHICKPEA FABA BEAN SOYBEAN Ascochyta blight (each crop with its own species) Septoria brown

spot Anthracnose Anthracnose

(?) Bacterial blight

Botrytis grey mould (Botrytis cinerea) Chocolate spot (Botrytis fabae)

Frog eye leaf spot (Cercospora)

Sclerotinia white mould Stemphylium blight Anthracnose

Aphanomyces root rot Phytophthora stem rot

Pythium & Rhizoctonia root rots Fusarium root rots

# 2-6 Tools

• Cultivars with resistance • Disease free seed • Seed treatment • Correct plant density, adequate nutrient

supply • Good weed control

GENERAL INFORMATION ON DISEASES

SK Ministry of Agriculture http://www.agriculture.gov.sk.ca/crops Then click on [Your Crop] production diseases

Ag Knowledge Centre Tel.: 1-866-457-2377, Got a question? E-mail: aginfo@gov.sk.ca http://www.agriculture.gov.sk.ca/AKC

SPG: http://saskpulse.com/growing/

Thank you !

Picture removed because of copyright protection