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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL AND PROTECTION TOOLS FOR INTEGRATED PEST MANAGEMENT OF MOSQUITOES AND FILTH FLIES

Location: Mosquito and Fly Research Unit

Title: Structure-Activity Relationships of 33 Carboxamides as Toxicants Against Female Aedes aegypti (Diptera: Culicidae)

Authors
item Wei Pridgeon, Yuping
item Becnel, James
item Bernier, Ulrich
item Clark, Gary
item Linthicum, Kenneth

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 17, 2009
Publication Date: March 1, 2010
Citation: Pridgeon, Y.W., Becnel, J.J., Bernier, U.R., Clark, G.G., Linthicum, K. 2010. Structure-Activity Relationships of 33 Carboxamides as Toxicants Against Female Aedes aegypti (Diptera: Culicidae). Journal of Medical Entomology. 47(2):172-178.

Interpretive Summary: The yellow fever mosquito Aedes aegypti is a medically important disease vector. Use of insecticides is one of the major method to control this insect pest. However, very few insecticides are available for mosquito control. Furthermore, mosquitoes have developed resistance to the few available insecticdes. We urgently need novel insecticides for mosquito control. As a part of our effort to search for new insecticides to control mosquitoes, toxicities of 33 carboxamides were evaluated against female adults of Ae. aegypti by topical application. The results of ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL, revealed that the most toxic compound of the 33 carboxamides tested was hexahydro-1-(1-oxohexyl)-1H-azepine and the least toxic compound was N,N-bis (2-methylpropyl)-3-phenyl-2-propenamide. Nine different categories of carboxamides (benzamide, phenyl-propenamide, propanamide, butanamide, butenamide, pentanamides, pentenamide, hexanamide, and hexenamide) showed different toxicities against female adults of Ae. aegypti. Our structure-activity analysis on the 33 carboxamides may be useful in guiding further

Technical Abstract: Aedes aegypti (L.) is the primary vector of both dengue and yellow fever. Use of insecticides is one of the primary ways to control this medically important insect pest. However, few new insecticides have been developed for mosquito control in recent years. As a part of our effort to search for new insecticides to control mosquitoes, toxicities of 33 carboxamides were evaluated against female adults of Ae. aegypti by topical application. On the basis of 24-h LD50 values after topical application, the most toxic compound of the 33 carboxamides tested was hexahydro-1-(1-oxohexyl)-1H-azepine, with an LD50 value as low as 0.4 'g per mosquito. On the basis of 24-h LD95 values after topical application, the most toxic compound of the 33 carboxamides tested was N-ethyl-2-methyl-N-phenyl-benzamide, with an LD95 value as low as 1.82 'g per mosquito. The least toxic compound was N,N-bis (2-methylpropyl)-3-phenyl-2-propenamide, with LD50 and LD95 values as high as 15.66 'g and 72.07 'g per mosquito, respectively. Nine different categories of carboxamides (benzamide, phenyl-propenamide, propanamide, butanamide, butenamide, pentanamides, pentenamide, hexanamide, and hexenamide) showed different toxicities against female adults of Ae. aegypti. Our structure-activity analysis on the 33 carboxamides may be useful in guiding further carboxamide modifications for the development of potential new insecticides.

Last Modified: 8/27/2014