
A historically wet September in the western Corn Belt has caused disease pressure to build in standing crops. Agronomists are finding Diplodia and Fusarium ear rots, weak stalks, lodging and elevated mycotoxin risk in corn, and fungal problems in soybeans.
Iowa's corn harvest was 7% complete versus a 20% five-year average, and Nebraska was nine points behind its average.
Lower grain quality and mycotoxin risk can reduce usable supply and widen basis discounts for affected corn. USDA's upcoming production update may show lower state yields in Iowa and Nebraska, supporting prices.
After 56 past bullish disease events, CORN moved a median -0.1% over 5 sessions (48% higher; middle half -1.5% to +1.6%), and +0.8% over 20.
After 12 past bullish disease events, SOY moved a median -0.5% over 5 sessions (42% higher; middle half -1.6% to +0.1%), and +0.5% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.