DISEASES

ANTHRACNOSE

• TWO FORMS: leaf blight and stalk rot.

• SYMPTOMS: Leaf blight: lesions varying in size, generally brown and round-shaped with yellowish area surrounding. First appear on leaf tip, moving to midrib, then produce large, dead spots. Stalk rot: Shiny, black streaks and blotches on the lower stalk. Internal stalk tissue can turn dark gray to brown and become shredded.

• TIME OF ATTACK: Anytime from seedling emergence to maturity. Leaf symptoms can begin in May; stalk rot symptoms usually appear in late August to mid-September.

• CONDITIONS FAVORING: Cool, wet weather.

• MANAGEMENT: Tillage, crop rotation, resistant hybrids. Scout and apply fungicide if necessary for foliar stage of disease.

GRAY LEAF SPOT

• SYMPTOMS: Small, linear, rectangular-shaped lesions, tan to gray in color. Lesions begin on lower leaves and spread upward.

• TIME OF ATTACK: Lesions generally appear near first tassel; disease spread continues through maturity.

• CONDITIONS FAVORING: Cloudy days with humid or wet conditions; heavy dew, fog or light rain. Continuous corn and reduced tillage also favor this disease.

• MANAGEMENT: Resistant hybrids, tillage, crop rotation, scouting and fungicide application if necessary

NORTHERN CORN LEAF BLIGHT

• SYMPTOMS: Elliptical brown to grayish to tan lesions from 1 to 6 in. long. If humid, lesions may have gray-green centers due to spores on dead tissue.

• TIME OF ATTACK: As early as silking, but more prevalent during later development stages.

• CONDITIONS FAVORING: Wet, humid weather; heavy dew and fog. Can also have higher rate in continuous corn and reduced tillage.

• MANAGEMENT: Resistant hybrids, tillage, crop rotation.

RUST

• FORMS: Southern and common

• SYMPTOMS: Small, circular raised blisters, reddish-brown in color. Found in common rust on both leaf surfaces; on southern rust on top-side of leaf surface.

• TIME OF ATTACK: Spores carried on spring winds from southern areas of U.S.

• CONDITIONS FAVORING: Common rust: cool, humid weather; southern rust: warm, humid conditions.

• MANAGEMENT: Resistant hybrids, scouting with fungicide application if necessary.

Editor's Note: Please keep in mind this is just a general, short list of pests and diseases to keep an eye out for. Others mentioned included chinch bugs, Japanese beetles, aflatoxin, ear rot and Goss's bacterial wilt/blight. For specific information for your location, contact your local Extension office or university.