
Iowa State University extension agronomists report mixed harvest yields, with drought-stressed soybean fields reporting yield losses and green stem syndrome cases. Tar spot and northern corn leaf blight were found in several corn fields in northwest Iowa, and harvest progress was 8% for corn and 27% for soybeans in north central Iowa.
Localized yield losses from drought and disease in Iowa add to supply tightness in a key producing state. The effect is limited to field-level reports rather than a state-wide estimate.
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, Soybeans 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.