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Effect of Ovasyn on Feeding Response, Mortality and Reproduction of Adult Bollworm

J. D. López, Jr. and M. A. Latheef


Ovasyn® (amitraz) was evaluated for its potential use as a toxicant and as an insect reproduction inhibitor (IRI) in an adult control program for bollworm, Helicoverpa zea (Boddie) using feeding attractants/stimulants. Ovasyn (1.5 EC) mixed with 1.0 M sucrose on a ppm AI weight:volume basis was fed to sex pheromone trap-captured males to determine toxicity. The 24 h LC90 was 583 ppm (95% CL of 468 to 916). Evaluation of 583 (1X LC90), 1,166 (2X), 2,915 (5X) and 10,000 ppm for effect on proboscis extension and gustatory responses of sex pheromone trap-captured males indicated that when compared with 1.0 M sucrose alone, there was a significant reduction at concentrations above 1,166 ppm for proboscis extension and at all concentrations for gustation. Mean lethal times were 319 min for 583 ppm, 160 for 1,166, 57 for 2,915 and 67 for 10,000; mean lethal time at 583 ppm was significantly slower from that at 2,915 and 10,000 ppm. At sublethal doses of 10, 25, 50, 75 and 100 ppm fed to laboratory-reared females within 24 h of emergence, there were no significant differences compared with control females fed only 1.0 M sucrose in larval hatch (%), mating frequency (mean no. of spermatophores per female), and survival of the hatched larvae to the pupal stage. At concentrations above 25 ppm, there was a significant reduction in gustatory response of laboratory-reared females compared with that of females fed only 1.0 M sucrose. Although Ovasyn was toxic to adult bollworm, its relatively low toxicity compared with other insecticides, its inhibition of proboscis extension and gustatory response and lack of significant IRI effects indicate limited potential for use of Ovasyn as a toxicant in adult control of bollworm with feeding attractants/stimulants.

Reprinted from Proceedings of the 1998 Beltwide Cotton Conferences pp. 1329 - 1333
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998