Submitted to: Journal of Pesticide Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 7, 2008
Publication Date: July 18, 2008
Citation: Lopez, J., Hoffmann, W.C., Latheef, M.A., Fritz, B.K., Martin, D.E., Lan, Y. 2008. Adult vial bioassays of insecticidal toxicity against cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae). Journal of Pesticide Science. 33:261-265. Interpretive Summary: Cotton fleahoppers are an early season insect pest of cotton that causes an estimated $18,000,000 loss in cotton production in Texas each year. The toxicity of 17 insecticides, encompassing four major insecticidal classes, was evaluated using laboratory-reared and field-collected cotton fleahoppers. There were 13-to-58-fold differences between toxicity of insecticides within an insecticidal class. Adult vial testing showed increased susceptibility in males versus females relative to the differences in insect weights between the male and females. These studies will significantly contribute to producers being able to select the most effective control product for cotton fleahoppers and aid in monitoring insecticidal resistance that may develop in fleahoppers.
Technical Abstract: Glass vials coated with several technical insecticides were used to determine the contact toxicity of insecticides on adult laboratory-reared and field-collected cotton fleahopper, Pseudatomoscelis seriatus (Reuter). For the 17 insecticides evaluated for laboratory-reared cotton fleahoppers, bifenthrin (pyrethroid), dicrotophos (organophosphate), thiamethoxam (neonicotinoid), and methomyl (carbamate) were the most toxic insecticides in their respective insecticidal classes based on LC50 values. There were significant differences between the LC50 values for the insecticides tested within each of the four insecticidal classes. There were 13-, 46-, 58-, and 31-fold differences between LC50 values for the insecticides in the pyrethroid, organophosphate, neonicotinoid, and carbarmate classes, respectively. Among fleahoppers collected from horsemint in May/June, adult vial testing showed increased susceptibility in males versus females. This difference can be attributed, at least in part, to differences in insect weights between the male and females since the females weighed significantly more than the males. Data presented herein provide a measure of acute potency of various insecticides against P. seriatus and serves as a measure of inherent relative differences between the insecticides. Baseline data will be useful for future comparison should suspicion of tolerance to these insecticides develop in field populations. These data are also important in comparing results from laboratory and field studies with cotton fleahoppers.