|Lopez, Juan De Dios|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2004
Publication Date: 6/14/2004
Citation: Lopez, J., Latheef, M.A. 2004. Adult vial technique for evaluating insecticidal toxicity to cotton fleahopper. In: Proceedings of the Beltwide Cotton Conferences, January 5-9, 2004, San Antonio, Texas. 2004 CDROM. Interpretive Summary: Cotton fleahopper is an important pest of cotton especially as the boll weevil is eradicated from the south-central cotton belt area because of reduced insecticide applications during the early fruiting period. Insecticidal control is the major technology available for preventing early square loss from this pest. Information is needed to identify the most effective insecticides and monitor for development of resistance to the insecticides. Adult fleahoppers were placed in glass vials containing insecticide residue and mortality was determined to evaluate various insecticides recommended for control of cotton fleahoppers. Insecticidal toxicity in decreasing order was dicrotophos (Bidrin), thiamethoxam (Centric), imidacloprid (Provado) and acephate (Orthene). Indoxacarb (Steward) was not very toxic to fleahoppers. Imidacloprid and thiamethoxam showed some systemic activity when the fleahoppers fed on green beans soaked in insecticide solutions, but some of this effect may have been due to contact with the treated surfaces. These data indicate that several of the newer insecticides are as effective as several of the older insecticides in controlling cotton fleahoppers.
Technical Abstract: 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.