Comparison of two sex pheromone trap designs for monitoring corn earworm and tobacco budworm (Lepidoptera: Noctuidae)

Two sizes of the Texas Pheromone (TP) trap and the International Pheromone Systems' (IP) Universal Moth trap with (IP1) and without (IP2) an insecticide strip were compared season-long for monitoring adult activity of the corn earworm, Helicoverpa zea (Boddie), and the tobacco budworm, Heliothis virescens (F.). Diameters of the bottom opening of the 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 TP75-50 TP50-25 IP1 equal to IP2. Mean efficiency ratios (calculated 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 and 0.03 for Heliothis virescens and 0.55, 0.28, and 0.12 for Helicoverpa 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 that TP trap efficiencies were similar for Helicoverpa zea and Heliothis virescens, IP trap efficiency was very low for Heliothis virescens, and the presence of insecticide strips in the IP traps had no detrimental effects on catches of either species. Linear regression equations were derived among all possible combinations of trap types. Highest r-squares 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)