Field Crop Diseases
Craig Grau
Plant Pathology
UW-Madison
Soybean
Corn
Wheat
Alfalfa
Signals Indicating SCN Problems
SCN
Weeds in patches breaking through the crop canopy
Detection of SCN on Soybean Roots
Diagnosis of
Soybean Cyst Nematode
Sclerotinia Stem Rot/White
Mold
Sclerotinia sclerotiorum
Pathogen x Soybean x Environment
Management of
Sclerotinia Stem Rot
Stem Canker Diagnosed
Characterized by brown stem lesions
Stem Canker
Leaf Retention – Variety Differences
Maturity differences or
disease?
If disease, which one?
Brown Stem Rot vs
Sudden Death Syndrome
Pattern of symptom development for SDS and BSR
SDS and SCN frequently found together in the same fields
Corn Anthracnose
Stalk phase most yield limiting
Major Corn Leaf
Diseases
in Wisconsin
Corn Leaf Health and
Yield
Fungicides?
Tassel and upper plant appearance can be used to evaluate corn health
Virus Pathogens of Small
Grains
Barley yellow dwarf virus
Corn is a host to BYDV; inoculum reservoir for BYDV
Leaf Rust of Wheat
Puccinia recondita
Wheat into corn
residue
Increases risk of Fusarium head scab
Aphanomyces Race 2 Resistant
Alfalfa Varieties
Powdery Mildew of
Soybean
80% soybean varieties resistant
Fungicides: Triazoles, Topsin-M
Frogeye Leafspot
Southern Wisconsin
Fungicides and Soybean Leaf Health
Wisconsin Soybean
Insect-Virus Complex
Soybean Viruses
Soybean mosaic virus, Alfalfa mosaic virus and
Bean pod mottle virus