TEMPORAL OCCURRENCE OF HELICOVERPA-ZEA LEPIDOPTERA, NOCTUIDAE (BODDIE), POPULATIONS ON CORN IN THE LOWER RIO-GRANDE VALLEY, UVALDE AND LUBBOCK, TEXAS

Corn earworm, Helicoverpa tea (Boddie), pheromone trap capture, larval infestation and adult emergence was monitored in corn in the Lower Ri o Grande Valley (26.2 degrees N, 98.0 degrees W), Uvalde (29,2 degrees N, 99.7 degrees W), and Lubbock (33.5 degrees N, 101.8 degrees W), Te xas. On a regional scale, larval infestation of fruiting corn and emer gence from pupae excavated from maturing corn fields provided discrete population events that were well separated by location. In most insta nces trap capture of adults appears, on a local scale, to be related t o these two events. However, in early season, the variability observed in trap capture and larval infestations on vegetative corn within reg ions provide difficulty in temporally defining the occurrence of meani ngful events related to these variables across regions. When ambient a ir temperatures and wind velocity occurring during trap capture peaks were compared to those occurring two days prior and two days after aft er the peaks only minor correlations were observed. The implications a re that trap capture values did not abruptly change with either signif icantly warmer or cooler temperatures or with increased or decreased z onal or meridional wind speed. We conclude that the atmospheric factor s used as independent predictor variables were not correlated with the response of corn earworm males to pheromone traps, or with the long-d istance atmospheric transport of populations into the trapping area. O ur data further show that simulated nocturnal within regions, provide a mechanism for determining the atmospheric systems available to trans port moths from one region to another.