Vegetable Program
Soil, Crop and Pest Management

Organic Insect Management in Sweet Corn

by Ruth Hazzard & Pam Westgate, Department of Entomology, University of Massachusetts Amherst

INTRODUCTION
When customers flock to markets in search of sweet corn, they want it to be of the highest quality — sweet, fresh, and worm-free. Yet, in ecological or organic production of sweet corn, achieving worm-free corn is one of the most difficult challenges. The mix of caterpillar pests and the timing of their infestation in corn depends upon your geographic location. In the Northeast three major caterpillar pests — corn earworm, European corn borer, and fall armyworm — invade ears and cause ugly feeding damage. Without effective controls, it is impossible to produce high quality corn throughout the season.

Organic pest management relies upon a variety of methods to reduce pest populations below economically damaging levels. Crop rotation, tillage of previous crop residues, mechanical barriers such as floating row covers, planting resistant or tolerant varieties, and conservation of existing beneficial organisms are all compatible with the methods described here, and may further enhance ear quality. Providing adequate fertility and water are also important for ear quality. For more information on these topics see the Organic Resource Guide to Insect and Disease Control and other resources listed at the end of this publication.

This fact sheet discusses an integrated strategy for controlling these three caterpillar species using methods that meet current certification standards for organic production. Any grower interested in methods that are safe for the applicator and the environment may be interested in this approach. The components of this strategy are 1) IPM monitoring to determine pest pressure and need for treatment and, if necessary, 2) a direct treatment of each ear with Bacillus thuringiensis (Bt) carried in vegetable oil to control corn earworm, 3) Trichogramma releases and/or foliar applications of Bt or spinosad to control European corn borer and/or 4) foliar applications of Bt or spinosad for fall armyworm control.

See the entire article here:
Organic Insect Management in Sweet Corn