Helminthosporium Leaf Blight is a fungal infection which results in spotting and blighting of the foliage. It appears as round-to-oval or linear tan spots up to roughly ½ to 1½ inches long. The lesions sometimes develop concentric zones and brown margins. Leaf sheaths, husks and ears are also infected by certain races. The fungus overwinters in corn debris.
Cultural: Crop rotation on a two to three year schedule and clean tillage help to reduce pathogen levels and
Monitoring: Fungicide treatments are not warranted in Kentucky most seasons, but be very watchful for the necessity to spray problem fields, especially in rainy seasons and late plantings (particularly plantings near older corn). When foliar fungicide sprays are warranted, they need to be applied with god coverage, early in the outbreak, at close intervals and before tassel emergence and ear formation.
Chlorothalonil - Apply as a foliar treatment by spray at 0.75 to 2 pt per acre with flowable formulations (F or L) or 0.63 to 1.5 lbs per acre for dry formulations (WP, DF or DG). (Note restriction on Chlorothalonil labels
relating to processing sweet corn. Also, not the restrictions on all uses related to livestock feed.
Mancozeb - Apply as a foliar treatment by spray at 2.4 pt per acre for flowable applications or 1.5 lb per acre for dry formulations (WP, DF Or DG).
Maneb 80 WP - Apply as a foliar treatment at 1.5 lb per acre.
Tilt 3.6 EC - Apply as a foliar treatment by spray at 2 to 4 oz per acre.