Mating Disruption of a Wild Population of Tobacco Budworm (Lepidoptera: Noctuidae) with Virelure

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Abstract
Virelure [16:1 ratio, (Z)-ll-hexadecenal: (Z)-9-tetradecenal] contained in Hercon flakes (0.64 cm2), Disrupt®, and applied by air at a dosage of 33 g (AI)/ha to cotton significantly reduced mating, and catches in pheromone traps, of tobacco budworms, Heliothis virescens (F.). Mating was reduced between 82 and 95% for 7 nights after treatment. The reduction in mating was 60% 9 nights after treatment and 26% 14 nights after treatment. Mating frequency as well as numbers of single- and multiple-mated females were significantly greater in the check than in the treatment. Numbers of virgin females were greater in the treatment than in the check but the difference was not significant. Catch in pheromone traps was reduced 89 to 98% for 7 nights after treatment. Capture reductions were 89% 14 nights after treatment and 72% 20 nights after treatment. Comparisons of numbers of male moths captured with numbers of matings showed that reduction in numbers captured does not necessarily reflect concomitant reductions in mating. Male population densities were equal in treatment and check plots on the night before treatment, but male densities declined in the treatment plot and increased in the check plot on the night after treatment. Thereafter, male densities remained lower in the treated plot than in the check (32–72% reduction) even though ll.3-fold (1,404:124) more males were being removed from the check plot by pheromone traps. Applications of cypermethrin (Cymbush®) decreased moth density but had no effect on mating frequency.