Does time of day for fungicide application matter??? With the heat that is the question I am getting the past few days. A couple AI searches said.... Yes... Early morning applications gave the highest yield response, when compared to mid to late afternoon. 2-5 bu per acre better in corn. Need to make sure that dew wetness in morning is not at leaf saturation where any application made will run off. If application will not run off, dew was actually favorable to getting product into the leaf. Overnight applications gave the lowest response as leaf stomates are typically closed when dark. Response was less than even late afternoon applications. One study in soybeans had night applications 1.5-3.5 bu/ac less than during daylight hours. For those with their own application equipment specific time of day applications could potentially give higher ROI.. Realistically spraying just a few hours a day would not get the acres covered that need to be covered.

Be sure what is in (or not in!) your fungicide surfactant! Some individuals are calling for fungicide applications to begin now... Prior to tassel fungicide applications made with a surfactant must be APE/NPE FREE!!! If your surfactant has APE/NPE in them, a before tassel application could likely result in arrested ear syndrome, causing very large yield losses!!! Be sure to check what you are applying if you are going before tassel! On a side note, I do not feel fungicide applications should begin now in the geography that I cover.