Foliar Health Basics: Northern Corn Leaf Blight Control
Northern corn leaf blight (NCLB), caused by the fungus Exserohilum turcicum, has been expanding its range throughout much of the United States due to warm, humid conditions; more minimum-tillage acres; and weather fronts that carry fungal spores great distances. These factors make control more important each year.
Severe NCLB infection may reduce yield by as much as 30 percent due to leaf damage that limits photosynthesis.
Northern corn leaf blight is most severe on continuous-corn acres, since it overwinters on corn residue. Crop rotation, tillage and selecting hybrids with resistant genetics can reduce disease pressure. However, sporulation can spread through different races of the disease found on distant fields, so any corn field or hybrid can be vulnerable.
Scout corn early – especially just before tasseling – during warm, wet weather to aid control. NCLB typically starts on lower leaves with cigar-shaped lesions that move up to the plant canopy if left untreated. The disease destroys leaf surface area, which reduces photosynthesis and, consequently, the plant’s ability to produce grain.
Signs of Infection
Cigar-shaped lesions first appear on lower leaves and progress upward through the plant. Late in the growing season, untreated infected leaves may look brown and tattered.
For best return on investment, plan to apply DuPont™ Aproach® Prima fungicide at VT (tassel) to R1. If NCLB signs appear early in the season, moving up fungicide application to V10 may be warranted to protect yield.
DuPont™ Aproach® Prima fungicide is not registered in all states. See your DuPont retailer or representative for availability in your state.
Headline® (BASF); Quilt Xcel® (Syngenta).
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