COMPARISON OF 2 SEX-PHEROMONE TRAP DESIGNS FOR MONITORING CORN-EARWORM AND TOBACCO BUDWORM (LEPIDOPTERA, NOCTUIDAE)

Two sizes of the Texas Pheromone (TP) trap and the International Phero mone Systems' (IP) Universal Moth trap with (IP1) and without (IP2) an insecticide strip were compared season-long for monitoring adult acti vity of the corn earworm, Helicoverpa zea (Boddie), and the tobacco bu dworm, Heliothis virescens (F.). Diameters of the bottom opening of th e outer cone and top opening of the inner cone of two sizes of the TP trap that were evaluated were 75 and 50 cm (TP75-50) and 50 and 25 cm (TP50-25), respectively. Based on the means for the number of males of both species caught per trap per week, the ranking of the traps was T P75-50 > TP50-25 > IP1 equal to IP2. Mean efficiency ratios (calculate d as the number of males caught per week divided by the number caught in the TP75-50) for the TP50-25, IP1, and IP2 traps were 0.47, 0.04, a nd 0.03 for Heliothis virescens and 0.55, 0.28, and 0.12 for Helicover pa zea, respectively. The difference in mean efficiency ratios between species was not significant for the TP50-25 trap, but the differences were significant for the IP1 and IP2 traps. The results indicated tha t TP trap efficiencies were similar for Helicoverpa zea and Heliothis virescens, IP trap efficiency was very low for Heliothis virescens, an d the presence of insecticide strips in the IP traps had no detrimenta l effects on catches of either species. Linear regression equations we re derived among all possible combinations of trap types. Highest r-sq uares were obtained for TP75-50 and TP50-25 traps for weekly and daily catches for Helicoverpa zea (r2 = 0.955 and 0.816, respectively) and for Heliothis virescens (r2 = 0.926 and 0.830, respectively).