Planning for Plant Health in Corn.

This year has offered us up and downs, but for the most part, we have come out ahead. Recent rains have reinvigorated the corn crop. As early fields begin tasseling, the question arises, "When is the best time to apply Veltyma or Headline AMP?"Veltyma’s long-lasting residual paired with BASF exclusive Plant Health gives it a wider window of application. In Indiana, this window begins with “first tassel – no hassle” timing and lasts up to the R3 growth stage. Traditionally, we recommend applying Headline AMP between VT, also known as full tassel, to R2, also known as blister stage. The photos above and below from Mississippi State University show VT and R1, respectively. The final photo from Purdue University depicts R2.I often hear Seed salesmen say to treat at "brown silk". Brown silk is not a recognized growth stage, while silking, or R1, (shown in the image above) is a growth stage. Corn silks turn brown when they have been successfully pollinated; however, once they turn brown they remain brown in color. Silks are typically mostly brown at the beginning of R2 or 10 to 14 days after silking begins (shown in the image below). Treating at the first sight of browned silks could put you in the optimum fungicide application window; however, waiting for crunchy brown silks that are visible from the highway makes you late to the game. If you are unsure what stage your crop is in, the best method of reproductive stage determination is to check ear development.Another question this year has been, when is it best to apply to fields with variable stands? Here are two approaches to applying to a field in varying growth stages. First, apply Veltyma or Headline AMP when the majority of the field is at VT. If the remainder of the field is still in vegetative stages, do not use an adjuvant with the application or verify that your adjuvant is NPE free.Another approach would be to apply Veltyma or Headline AMP when all of the field has reached VT but not exceeded R2. An adjuvant may be used in this application. If risk of disease is high, the first option may provide better disease control. Remember, always apply Veltyma at 7 fl oz per acre or Headline AMP at 10 to 14.4 fl oz per acre. If conditions remain humid and warm, we could be in for another surprisingly heavy disease year in 2021!