Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2011
Publication Date: December 18, 2011
Citation: Lopez, J., Latheef, M.A., Hoffmann, W.C. 2011. Effect of Hexaflumuron on feeding response and reproduction of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae). Southwestern Entomologist. 36(3):247-259. Interpretive Summary: Bollworms are a serious pest of cotton throughout the United States and must be controlled due to the economic damage they cause. Insect growth regulators (IGR) are non-traditional pesticides that prevent insects from maturing into adults, and have low mammalian and environmental toxicity with reduced risk to nontargeted insects. Studies were conducted to characterize the toxic effect of an IGR (hexaflumuron) on proboscis extension, ingestion and reproduction of adult bollworms, and survival of bollworm offspring when the hexaflumuron was integrated into a feeding stimulant solution. Data suggest that hexaflumuron has value as a slow-acting toxicant used for suppression of bollworm on field crops. Application of the IGR in a feeding stimulant solution provides an additional tool for farmers and researchers to control and mitigate damage to cotton caused by bollworms.
Technical Abstract: 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 (ppm) was evaluated in the laboratory against bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) for toxicity, proboscis extension, gustation and reproduction. We wanted 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 carbohydrate sources. The intent is to exploit this nocturnal behavior of the adult bollworm as a pest management strategy for suppression of the insect using the adult feeding approach. For feral male boll worm, the lethal concentration (LC50) values for 24 and 48 h responses were 295.6 and 96.03 ppm, respectively. These values were significantly different. Hexaflumuron significantly depressed gustatory response of laboratory-reared females at 100 ppm and above. Proboscis extension response was not significantly depressed up to 25 ppm. Percentage hatch of eggs oviposited by laboratory-reared females was significantly reduced at concentrations of 5.0 ppm and above. Percentage hatch of eggs was not significantly reduced when laboratory-reared males fed hexaflumuron were mated with laboratory-reared females. This suggests that hexaflumuron possibly acted as an ovicide. Hexaflumuron did significantly reduce mating frequency in females; however, there was no consistent trend in reduction in mean numbers of spermatophores per female. We posit that hexaflumuron could be a useful toxicant in a feeding stimulant mixture for suppression of bollworm.