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Get Early Control of Gray Leaf Spot

February 16, 2019

This chart shows the yield advantage of Trivapro fungicide

Diseases present: Gray leaf spot, Northern corn leaf blight, common rust. Averaged across 6 Syngenta cooperator trials 2014 – 2016. Trial locations: IL (2), WI, DE, NE, SD.

Gray leaf spot is one of the biggest yield-robbing corn diseases in the U.S., and there’s no sign of it slowing down any time soon. Make sure you’re prepared to fight this disease, should it show up in your field this season.

Disease development

  • An extension expert at the University of Wisconsin-Madison says gray leaf spot can increase rapidly on susceptible hybrids when temperatures are warm and humidity is greater than 90%.
  • The chance of gray leaf spot infection can increase in fields with corn-on-corn rotations and minimal tillage, due to higher levels of pathogens left in the crop debris.

What to look for

  • The University of Iowa Extension says gray leaf spot always starts in the lower canopy and progresses up, so when scouting start from the bottom of the crop.
  • Lesions begin as small oval, light-tan spots before expanding into long, narrow and rectangular lesions.
  • Lesions typically expand parallel to leaf vines and can later turn gray.
  • Yellow or orange halos may surround the lesions.

The University of Wisconsin-Madison extension expert also says that yield loss can be greater if lesions reach ear leaves 2 weeks before or after tasseling, meaning that managing gray leaf spot early is crucial. Efficient management practices include selecting resistant hybrids, crop rotation and fungicide application.

If you plan to incorporate a fungicide into your gray leaf spot management plan, consider Trivapro® fungicide. Trivapro provides harder-working, longer-lasting residual disease control for corn diseases, including gray leaf spot, Northern corn leaf blight, rusts and other key foliar and stalk diseases, as well as plant-health benefits. Protect your corn from application to harvest with preventive and curative activity from Trivapro.

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