Egg-Laying Pattern of Helicoverpa zea1 in Sweet Corn: A New Pest Management Prospect

Abstract

The corn earworm, Helicoverpa zea (Boddie), is a major insect pest of maize (Zea mays L.), cotton (Gossypium hirsutum L.), and vegetable crops. Maize silk is a favorite egg-laying site of H. zea. However, other parts of the maize plant might be even more attractive for oviposition by H. zea. Under field conditions and in insect-proof cages in a greenhouse, egg-laying distribution patterns were assessed on a late and an early sweet corn cultivar, i.e., Java (Technisem) and Garrison (Syngenta), respectively. Maize tassels on both cultivars were the main egg-laying sites of the pest. In insect-proof cages, at the maize silking stage, more than 60% of the total number of eggs collected were on tassels. In the field, oviposition by H. zea began at tassel emergence, and more than 80% of the total number of eggs were collected from tassels. Egg distribution on leaves and silk varied according to the sweet corn cultivar. The findings offer new prospects to control H. zea. The tassel emergence stage is the best period for controlling H. zea in maize fields and the best phenological stage to use maize as a trap crop for the pest.