Corn Disease Risk Maps

For period of July 31 – Aug 29, Date of Issue: August 1, 2021 
DEKALB® corn field at late season
CLICK ON DISEASE FOR RISK FORCAST
One-Month Weather Outlook

Over the next 30 days temperatures will be warmer than normal north of I-80 and normal farther south.  It will be dryer west of I-35, and wetter than normal in OH, IN and KY.  During the next two weeks temperatures are predicted to be warmer than normal for the entire Corn Belt.  Rainfall will be higher than normal east of the Mississippi River, and normal or dryer for areas west of the River.

Gray Leaf Spot Risk Summary

The risk for gray leaf spot is moderate to high in the southern half of the Corn Belt.

Next two-week risk interpretation 

Weather conditions are moderately or highly favorable for GLS in areas south of I-80.  In at-risk areas consider treating susceptible hybrids that have not reached dent stage. In areas of yellow, susceptible hybrids on corn-corn or no-till ground with a history of the disease are at higher risk than moderate. 

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

Over the next 30 days temperatures will be warmer than normal north of I-80 and normal farther south.  It will be dryer west of I-35, and wetter than normal in OH, IN and KY.  During the next two weeks temperatures are predicted to be warmer than normal for the entire Corn Belt.  Rainfall will be higher than normal east of the Mississippi River, and normal or dryer for areas west of the River.​

​Northern Leaf Blight Risk Summary ​

The risk of northern corn leaf blight is moderate or high east of the Missouri River.

​Next two-week risk interpretation  ​

Conditions continue to be highly or moderately favorable for NCLB in the eastern Corn Belt. In at-risk areas spray susceptible hybrids where the disease is seen on the middle or upper leaves.  Late-planted corn is at higher risk.

ONE-MONTH RISK MAP
One-Month Weather Outlook

Over the next 30 days temperatures will be warmer than normal north of I-80 and normal farther south.  It will be dryer west of I-35, and wetter than normal in OH, IN and KY.  During the next two weeks temperatures are predicted to be warmer than normal for the entire Corn Belt.  Rainfall will be higher than normal east of the Mississippi River, and normal or dryer for areas west of the River.​

Southern Rust Risk Summary

The risk of southern corn rust is moderate for much of the Corn Belt.

Next 2-week risk interpretation 

Conditions are moderately favorable across the Corn Belt for southern rust.  In areas of yellow, spray if the disease is found or reported nearby. Late-planted corn is at higher risk. 

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

Over the next 30 days temperatures will be warmer than normal north of I-80 and normal farther south.  It will be dryer west of I-35, and wetter than normal in OH, IN and KY.  During the next two weeks temperatures are predicted to be warmer than normal for the entire Corn Belt.  Rainfall will be higher than normal east of the Mississippi River, and normal or dryer for areas west of the River.

Common Rust Risk Summary

The risk of corn common rust significantly decreases as temperatures increase.

Risk interpretation 

The increase in temperatures for much of the Corn Belt significantly reduces the risk of common corn rust to susceptible hybrids.  In areas of orange, consider spraying susceptible hybrids if disease is detected in the upper canopy.  In eastern regions on late-planted corn, the disease may pick up again in the fall. 

Common Rust - Corn Leaf Lesions 1
ONE-MONTH RISK MAP
One-Month Weather Outlook

Over the next 30 days temperatures will be warmer than normal north of I-80 and normal farther south.  It will be dryer west of I-35, and wetter than normal in OH, IN and KY.  During the next two weeks temperatures are predicted to be warmer than normal for the entire Corn Belt.  Rainfall will be higher than normal east of the Mississippi River, and normal or dryer for areas west of the River.

Corn Tar Spot Risk Summary

In areas where tar spot was previously reported, the risk is high or moderate.     

 Next two-week risk interpretation 

Weather conditions continue to be highly favorable to tar spot east of the Mississippi River and north of I-70. In at-risk areas consider spraying if the disease is detected.

Tar spot of corn
ONE-MONTH RISK MAP
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