Effect of hexaflumuron on feeding response and reproduction of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae).
Hexaflumuron (Consult® 100 EC, Dow AgroSciences) is an insect growth regulator that inhibits chitin synthesis. The efficacy of hexaflumuron mixed with 2.5-M sucrose (mg-1) was evaluated for toxicity, proboscis extension, gestation, and reproduction of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), in a laboratory. The intention was to determine whether or not hexaflumuron could be used as a toxicant in a feeding-stimulant mixture for suppression of bollworm. Newly emerged bollworm adults actively seek carbohydrates. For feral male bollworm captured in pheromone-baited traps, the lethal concentration (LC50) values 24 and 48 hours after exposure were 295.6 and 96.03 mg-1, respectively. These values were significantly different. Hexaflumuron at 100 mg-1 or more significantly depressed gustatory response of feral male and laboratory-reared male and female bollworms. There was no significant difference in proboscis-extension response between bollworms fed 1.0 and 2.5 M sucrose solutions. Percentage hatch of eggs oviposited by laboratory-reared females during 3 consecutive days was significantly less at concentrations of 5.0 mg-1 or greater of hexaflumuron when compared with females fed 2.5-M sucrose. However, when laboratory-reared males fed hexaflumuron were compared with males fed 2.5-M sucrose solution, percentage of eggs that hatched was not significantly less. This suggests that hexaflumuron acted as an ovicide. It is posited that hexaflumuron could be a useful toxicant in a feeding-stimulant mixture for suppression of bollworm.