Presentation on theme: "Asian Soybean Rust: Scouting & Sampling in Illinois"— Presentation transcript:
1 Asian Soybean Rust: Scouting & Sampling in Illinois University of IllinoisState Soybean Rust TaskforceSuzanne Bissonnette,IPM Educator
2 Brand New Editions Be ready with effective scouting
3 Assessment of Disease Incidence: Severity: The number of plants (or units) affected by disease with in a populationie 47 of 100 plants diseased= 47% incidenceSeverity:The measure of actual damage done by diseaseSome keys measure severity of the whole plantSome keys measure severity on infected leaves
4 Assessment of Rust Severity Researchers generally assess rust disease as disease severity of key leaves.Rust pustules only occupy a maximum of 37% of the area on a leaf. This is equivalent to 100% infection of that leaf.
5 Rust Severity Assessment Key A= actual amount of tissue occupied by pustules (Cobb scale)B= equivalent damage to leaf (Modified Cobb)* If A=18.5% area occupied by pustules, this is equivalent to B=50% damage to the leaf*
6 Disease Scouting for Soybean Rust Incidence U of I recommends determining incidence rather than severity for scouting protocol.Note: one plant with any amount of rust in 100 plants = 1% incidence
7 Illinois Scouting – “Look Low As You Go” When scouting examine the lower quarter of soybean plantsExamine 20 plants in 5 random locations in a field.Examine the undersides of leaves for pustules.
8 Soybean Rust Scouting Field Pattern Scout in a zig-zag pattern in the field making observations of 20 plants in 5 locations
9 Foliar Symptoms Soybean Rust not distinguishing must look closer
10 Symptoms & Signs of Soybean Rust Look for pustules and chlorosis on undersides of lower leaves before flowering.Severity increases with time and rainfall – lesions can develop on all leaves followed by defoliationObserve chlorosisLook at underside of leavesObserve pustules with hand lens
17 Illinois Scouting – “Look Low As You Go” If you suspect rustcollect 20 leaflets exhibiting symptoms.Place flat, dry leaflets between paper towels.Double bag suspect leaflets in zip lock bags.Clearly label sample.
18 IL Extension Distance Diagnostics (DDDI Available in all Units in Illinois) Sample Processdigital images submitted for you by UnitDiagnosis reply to UnitSamples may then require submission to U of I Plant Clinic.
19 IL Extension Distance Diagnostics (DDDI Available in all Units in Illinois) No fee for DDDI samples.Plant Clinic fee ($12.50) paid by ISPOB if sample is pre-screened with DDDIExpect to pay overnight shipping prior to detection in state.
22 Prepare Yourself for Soybean Rust Before It Arrives Equip sprayers with proper nozzlesPre-plan fungicide spray programWho? How much acreage/day?Plan to scout “Low as you go” weeklyTake representative sampleGet it properly identified
23 Presentation by S. Bissonnette, D. Bowman, D. Malvick, M. Montgomery Acknowledgements:Presentation by S. Bissonnette, D. Bowman, D. Malvick, M. MontgomeryAcknowledge slides & jpg’s from G. Hartman, M. Miles, USDA-ARS, R. Frederick, M. Palm and University of Illinois Extension