What are we seeing in the field?
The most common diseases we’ve seen in 2018 across KY/TN/IN has been Grey Leaf Spot, Northern Corn Leaf Blight, Diplodia Leak Streak, and Physoderma Brown Spot. Humidity has been a big factor in disease development and progression. Crop rotation, crop residue management and hybrid selection are just a few key preventative practices to reduce disease development.
Grey Leaf Spot
Long, rectangular lesions that stay between leaf veins, fungus survives on old infested crop reside, rain splashes fungus onto the plant causing the infection (which is why symptoms typically are seen on lower leaves), likes warm and humid temps.Grey leaf spot lesions
Northern Corn Leaf Blight (NCLB)
Long, narrow cigar-shaped lesions, typically black fungal spores can be seen within the lesion, fungus overwinters on old infested crop residue, rain splashes fungus onto the plant causing the infection, likes moderate temps and wet and humid weather.Northern Corn Leaf Blight lesions
Diplodia Leaf Streak
Long streaks with tapered ends often mistaken as NCLB, has small repetitive circles and pimple-like spores within the lesion, fungus survives on old infested crop reside, rain splashes fungus onto the plant causing the infection, likes warm and wet weather conditions.Early Diplodia Leaf Streak lesions Mature Diplodia Leaf Streak lesions
Physoderma Brown Spot
Round, purple spots down midrib and on leaf sheath or husks with bright yellow streaking appears in bands across the leaf, fungus survives on old infested crop reside, fungus moved into corn whorl by splashing rain and wind, likes warm and wet conditions and extended periods of water sitting inside the corn whorl.Yellow Banded Streaking Purple Spotting down the midrib