Euxesta spp. NEW PEST IN Zea mays L. VAR. rugosa: ASSOCIATION WITH Heliothis zea ATTACKS IN SPRING AND SUMMER SEEDS

The silk fly of maize ( Euxesta spp. Loew, 1868) appeared in 2005 in Santa Fe (Argentina), causing damage to the ears. The attacks are related to temperature, crop growth stage and previous attack of other pests. For this new pest, we determined the species present, the damage on Bt sweet corn plantings in two seasons (August and February), the association of attacks with Heliothis zea (Boddie, 1850) and the presence of parasitoids. Larvae counts of H. zea and Euxesta spp. began in the phenological stage of R2 and ended in R5 and consisted of removing at random from each batch (three for each planting season) four ears. In laboratory we determined the percentage of damage on the ears and number of larvae of Euxesta spp. and H. zea , discriminated by size. Fly was identified as E. eluta , damage was greatest in the early spring planting corn. Attacks were correlated with H. zea .