It may be a bit too early to accurately predict the potential for significant foliar fungal diseases in this year’s crop. However, the agronomy team at Hoegemeyer will be keeping a close eye on disease development in the days and weeks leading up to tasseling. The summer of 2014 saw an unusually high amount of foliar disease in corn, especially in Iowa, eastern Nebraska, and northwestern Missouri. Last year’s months of May and June were filled with consecutive days of rain and moderate-to-below normal temperatures. This set us up for the presence of a foliar disease called Northern Corn Leaf Blight (NCLB) which is normally confined to the central and eastern corn belt. The disease itself can be fairly aggressive if conditions remain favorable for infection, especially in hybrids that are susceptible. High risk fields would include those with high amounts of corn residue, fields with a history of the disease in 2014 and especially those with average-to-below average Northern Leaf Blight ratings.
2015 has been somewhat déjà vu in regards to the late May and early June weather patterns. Very recently, there have been reports of suspected Northern Leaf Blight in fields in eastern Nebraska. The good news is that it appears we may finally break into a somewhat more normal summer weather pattern with temps climbing well into the 80’s with 90’s in the 7 day forecast. This disease will struggle to infect and progress with these warmer temps. However, it is possible infection has already occurred in some fields.
Growers are encouraged to consult with their Hoegemeyer District Sales Manager and/or Hoegemeyer Agronomist(s) as we approach the optimum period for fungicide applications which is typically VT (tassel) to R2 (blister). It will pay to begin checking fields starting now. Several foliar fungicides have good activity against this disease as well as others. If specifically targeting Northern Leaf Blight, one does not want to delay the decision to spray if the disease is present. Last year there were likely several fields that were sprayed too late and did not benefit fully from the fungicide application.
A follow up informational blog will be posted on this topic again within the next 2 weeks as we are better able to evaluate potential foliar disease development in this year’s corn crop.
Northern Corn Leaf Blight Lesions in a corn field in western IA June 30th 2014 (left) and eastern NE June 18th (right).