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The Problem

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Gray Leaf Spot

  • Cause: Cercospora zeae-maydis
  • Environment: Warm, humid conditions, particularly in fields with high corn residue.
  • Timing: Initial infection typically occurs early in the season, but symptoms most commonly appear from tasseling through grain fill (VT–R5).
  • Appearance: Narrow, rectangular lesions that are gray to tan in color and restricted by leaf veins. Lesions develop on lower leaves first and progress upward through the canopy.
  • Risk: Yield loss, premature leaf death and reduced kernel size.
Gray leaf spot lesions on corn leaf

Gray leaf spot lesions on corn leaf

Close up of gray leaf spot lesions on a corn leaf

Close-up of gray leaf spot lesions on corn leaf

Close up of gray leaf spot lesions on a corn leaf

Corn leaf infected with gray leaf spot

Corn leaf with narrow gray rectangular lesions between leaf veins.

Leaf loss reduces photosynthesis during grain fill

Severe gray leaf spot damage causing loss of green leaf area.

Rectangular gray leaf spot lesions form between leaf veins

Corn plant showing gray leaf spot lesions spreading through the canopy.

Gray leaf spot spreads upward through the canopy

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Understanding Gray Leaf Spot in Corn

Gray leaf spot develops when Cercospora spp. fungi infects corn leaves. It can persist within crop residue from previous seasons. The disease can progress rapidly under favorable conditions and may go unnoticed early, increasing its impact later in the season. The disease can manifest in three key ways:

Lower canopy infection

Lesions begin on lower leaves where humidity and leaf wetness persist longer

Canopy progression

Lesions spread upward through the plant, reducing effective leaf area

Yield impact

Loss of green leaf tissue during grain fill reduces kernel development

Why Gray Leaf Spot Matters

Gray leaf spot is one of the most economically important foliar diseases of corn. When unmanaged, it can significantly reduce yield potential by limiting photosynthesis during critical reproductive stages. Effective disease management is essential to protect yield, standability and crop performance.

 

Since gray leaf spot thrives in warm, humid environments and overwinters in corn residue, it is most common across the central and eastern Corn Belt like Illinois, Indiana and Kentucky, where humidity and areas with continuous corn acres drive higher pressure.

Why Gray Leaf Spot Matters

The Solution

Use Miravis Neo to Fight Gray Leaf Spot

  • Active Ingredients: ADEPIDYN® technology, Azoxystrobin, Propiconazole
  • Why Miravis Neo Works: Delivers dual-yield protection with broad‑spectrum disease control with a long‑lasting residual and added plant‑health benefits.
  • Crops: Corn and Soybeans
  • Benefits: Delivers consistent, comprehensive control and is the only premium fungicide labeled for Fusarium / Gibberella ear rots.

Why Use a Cleaner & Greener Fungicide?

From disease to crop stress, you don't know what the season will bring so your yield potential needs protection on all fronts! That's why only Cleaner & Greener fungicides are powered by exclusive ADEPIDYN® and SOLATENOL® technologies to provide a step change in broad-spectrum disease control and protection from crop stress like drought.

Cleaner & Greener