Corn Disease Risk Maps

For period of July 30 – August 29, Date of Issue: July 31, 2022 
DEKALB® corn field at late season
Delaro Complete
CLICK ON DISEASE FOR RISK FORECAST
One-Month Weather Outlook​

For the next two weeks and continuing through the next 30 days temperatures are expected to be above normal for the entire region.  Less-than-normal precipitation will fall west of the Mississippi River with normal amounts to the east and increasing toward the coast.  

​Northern Leaf Blight Risk Summary ​

The risk level of northern leaf blight is moderate or high for the Corn Belt.  

​Next two-week risk interpretation  ​

During the next two weeks conditions are favorable for NCLB across the Midwest.  In at-risk areas scout susceptible hybrids, especially in fields with a history of this disease in prior years.  Consider spraying an effective fungicide if disease symptoms are found on the ear leaf or higher.

ONE-MONTH RISK MAP
One-Month Weather Outlook

For the next two weeks and continuing through the next 30 days temperatures are expected to be above normal for the entire region.  Less-than-normal precipitation will fall west of the Mississippi River with normal amounts to the east and increasing toward the coast.       

Gray Leaf Spot Risk Summary

The risk level for grey leaf spot has increased from Illinois to the east coast. 

Next 2-week risk interpretation 

During the next two weeks conditions are favorable for the development of gray leaf spot for most of the Corn Belt, with broad areas currently at high risk.  Consider spraying a fungicide if lesions are observed above the ear leaf and the corn has not reached growth stage R5.  

Gray Leaf Spot - On Leaf
ONE-MONTH RISK MAP
map
One-Month Weather Outlook

For the next two weeks and continuing through the next 30 days temperatures are expected to be above normal for the entire region.  Less-than-normal precipitation will fall west of the Mississippi River with normal amounts to the east and increasing toward the coast.      

Southern Rust Risk Summary

Southern corn rust has remained limited to the southwest quarter of the forecast region.      

Next 2-week risk interpretation 

Weather conditions are moderately favorable for SCR in the southern part of the Corn Belt.  As spores move into the area, the risk is likely to increase.  Consider spraying an effective fungicide if SCR is found or reported nearby and the corn kernels have not dented.  

An example of Southern Rust on corn leaves.
ONE-MONTH RISK MAP
image
One-Month Weather Outlook

For the next two weeks and continuing through the next 30 days temperatures are expected to be above normal for the entire region.  Less-than-normal precipitation will fall west of the Mississippi River with normal amounts to the east and increasing toward the coast.  

Corn Tar Spot Risk Summary

The risk is moderate to high for most of the areas that have experienced tar spot in previous seasons.         

Next two-week risk interpretation 

Over the next two weeks conditions remain favorable or moderately favorable for tar spot in most of the areas where tar spot was observed in prior seasons.  Scout fields in at-risk areas and consider spraying an effective fungicide if symptoms are observed.  No midwestern hybrids have been observed to be fully tolerant to the disease.  Irrigated fields are at higher risk.         

Tar spot of corn
ONE-MONTH RISK MAP
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