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Gamma Cyhalothrin (DowAgro). First year field performance of XDE-225. Paper presented June 2001.

Paper presented at: Pacific Branch Entomological Society of America 85th Annual Meeting Marriott Hotel, Park City, Utah June 24-27, 2001 -- see program at: http://pbesa.prosser.wsu.edu/index.htm

XDE-225 (GAMMA CYHALOTHRIN), A NEW FULLY-RESOLVED PYRETHROID PRODUCT Ð FIRST YEAR FIELD PERFORMANCE

J. M. Richardson1, M. B. Hertlein2, E. A. Flora3, B. Bisabri4, and M. D. Culy2

1 Dow AgroSciences, 9330 10th Avenue, Hesperia, CA 92345, USA

2 Dow AgroSciences, 9330 Zionsville Rd., Indianapolis, IN 46268, USA

3 Dow AgroSciences, 7521 W. California Ave., Fresno, CA 93706, USA

4 Dow AgroSciences, 109 Canon Dr., Orinda, CA 94563, USA

XDE-225 (gamma cyhalothrin) is a technologically advanced "pure" (totally resolved) pyrethroid isomer. Whereas lambda cyhalothrin is a mixture of two isomers, one active and one inactive, gamma cyhalothrin contains only the active isomer. By removing the inactive isomer, field rates of one-half the active ingredient would be expected to provide similar control, compared to the non-resolved product. This latest-generation pyrethroid is being developed through Pytech Chemicals, a joint venture between Dow AgroSciences and Cheminova.

In the US, 43 field studies were conducted on alfalfa, cole crops, tomatoes, cotton, sweet corn, grain corn, rice, soybeans and peanuts in 2000. The studies were designed to make direct comparisons of selected rates of lambda cyhalothrin to gamma cyhalothrin at one-half those rates. Over a broad range of insect species, first-year results suggested that gamma cyhalothrin was twice as active as lambda cyhalothrin, on a grams a.i./ha basis. Statistically, differences in efficacy could rarely be detected. However, trends suggested that lambda cyhalothrin had faster knockdown, while gamma cyhalothrin exhibited longer residual activity. No symptoms of phytotoxicity were detected with either product, nor were instances of secondary pest resurgence observed in any of the studies.