foliar disease management in pulses what are the tools and ... · steps for disease management...
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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: [email protected] http://www.agriculture.gov.sk.ca/AKC
SPG: http://saskpulse.com/growing/
Thank you !
Picture removed because of copyright protection