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Adult Vial Technique for Evaluating Insecticidal Toxicity to Cotton Fleahopper

Juan D. López, Jr. and M.A. Latheef


An adult vial test was used to determine contact toxicity of technical dicrotophos (Bidrin ® 8), acephate (Orthene ®), imidacloprid (Provado ® 1.6), thiamethoxam (CentricTM 40 WG) and indoxacarb (StewardTM ) to cotton fleahopper, Pseudatomoscelis seriatus (Reuter). These data are the first published for this species. Lethal concentrations [LC50s(95% CLs)] at 24 h for dicrotophos and acephate were 0.1886 (0.1696-0.2066) and 7.6630 (5.9272-9.0815) µg/vial, respectively. These values were significantly different. For imidacloprid and thiamethoxam, LC50s(95% CLs) at 24 h were 0.6583 (0.4422-0.9157) and 0.3855 (0.2724-0.5149) µg/vial, respectively. These values were not significantly different. Both imidacloprid and thiamethoxam were significantly less toxic than dicrotophos but significantly more toxic than acephate. Contact with indoxacarb did not significantly influence fleahopper mortality. Systemic toxicity of imidacloprid and thiamethoxam was studied by soaking green beans, Phaseolus spp. in water containing different concentrations of Provado 1.6 and Centric 40 WG. LC50s (95% CLs) at 24 h for Provado and Centric were 74.8052 (54.9742-97.0045) and 36.0169 (20.8745-53.2132) µg/ml, respectively. These values were significantly different and were much higher than those for the same chemicals by contact.

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Document last modified 04/27/04