Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2000
Publication Date: N/A
Interpretive Summary: Insect repellents intended for application to skin are seldom evaluated for other kinds of biological activity. When scientists at the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida and the University of Florida tested the insect repellent deet and two experimental repellents against mosquitoes in artificial containers (e.g., cups, glasses, cans, bottles) they found that the experimental repellents kept female Asian tiger mosquitoes from laying eggs in the containers and that the repellents in the water in the containers killed the mosquito larvae. The length of time of ovipositional repellency and larvicidal activity was more than 6 months in some tests. But one problem with the use of the experimental repellents for mosquito control in containers is that they may be poisonous to the other organisms that live with the mosquitoes in the containers; and some of these organisms may play a beneficial role as mosquito predators. Consequently, tests were made to determine the safety of the experimental repellents to six different kinds of invertebrate animals commonly found with Asian tiger mosquito larvae in artificial containers in nature. The results of the tests showed that the experimental repellents were safe to the nontarget organisms when used in concentrations that prevented egg laying by the Asian tiger mosquito, or that killed mosquito larvae in the water. The results of this study will be used to help develop an environmentally acceptable method for the treatment of artificial containers with repellents so that the containers do not become infested with mosquito eggs or larvae.
Technical Abstract: Toxicity of 3 mosquito oviposition repellents,AI3-22542 or deet, AI3-35765, and AI3-37220 to 6 aquatic nontarget invertebrates was evaluated in the laboratory. The 24 h LC 50 values for Cypriceras sp. (Ostracoda), Moina sp. (Cladocera), Eucyclops aqilis Koch (Copepoda), Strelkovimermis spiculatus Poinar & Camino (Nematoda), 1st and 4th instar Toxorhynchites amboinensis Doleschall larvae (Diptera) and 4th instar Chironomus decorus Johannsen larvae (Diptera) ranged from 0.012% - 0.127% or 120-1270 ppm. Cypriceras sp., Moina sp., E.aqilis, 1st instar Tx. amboinensisand 4th instar C. decorus were generally more sensitive to the test repellents than male and female S. spiculatus and 4th instar Tx. amobinensis. Male S. spiculatus was more sensitive to the repellents than its females and this was probably due to the small body size of the male. All invertebrates were generally more sensitive to AI3-37220 than to deet and AI3-35765. The experimental repellents were considered safe to the aquatic nontarget orgainsms when employed as oviposition repellents for Aedes albopictus (Skuse) mosquitoes.