Despite a lot of variability in development, there are corn fields that are now in the application window for an early fungicide application. The recommendation for the early application is from 7 to 10 leaf corn (V5 to V8). One of the main drivers for a fungicide application now is the thought that since a herbicide is already being applied, the addition of a fungicide will eliminate an extra application cost at tasseling (VT). The caution here is to not wait to control weeds if they are a problem, just to save a pass. The herbicide application is the most important application at and prior to V5-V7 stages and the economics of a weedy crop far outweigh an additional application cost. Be sure to consult your chemical supplier to determine what herbicide and fungicide mixes are labelled and safe for the crop. Spray coverage is important, so it is recommended to keep water volume at 15 gal/ac or higher to get as much leaf coverage as possible. Results have varied over the past few seasons; however, generally fungicide suppliers are reporting a range of 4 to 8 bu/ac response. This is generally a lower yield response than the VT timing where chemical suppliers are reporting an average response of 7 to 10 bu/ac advantage. In the end, I think all fields need to be assessed on an individual basis. Consult with your Maizex Seed Specialist or your chemical supplier to determine the right prescription for your fields.

Cain Templeman, CCA-ON, Maizex Seeds Yield Specialist, Huron and Perth Counties
Twitter: @Cain_Templeman