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The naturally derived insecticide spinosad is highly toxic to Aedes and Anopheles mosquito larvae
Author(s) -
Bond J. G.,
Marina C. F.,
Williams T.
Publication year - 2004
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/j.0269-283x.2004.0480.x
Subject(s) - spinosad , aedes aegypti , biology , larvicide , toxicology , anopheles gambiae , anopheles albimanus , anopheles , larva , mosquito control , veterinary medicine , pesticide , ecology , malaria , medicine , immunology
. Spinosad is a naturally derived biorational insecticide with an environmentally favourable toxicity profile, so we investigated its potency against mosquito larvae (Diptera: Culicidae). By laboratory bioassays of a suspension concentrate formulation of spinosad (Tracer ® ), the 24 h lethal concentration (LC 50 ) against Aedes aegypti (L.) third and fourth instars was estimated at 0.025 p.p.m. following logit regression. The concentration–mortality response of third‐ and fourth‐instar Anopheles albimanus Weidemann did not conform to a logit model. The LC 50 value of spinosad in Anopheles albimanus was 0.024 p.p.m. by quadratic linear regression. A field trial in southern Mexico demonstrated that spinosad 1 p.p.m. compared with the standard temephos (Abate ® ) 1% granules 100 g/m 3 water prevented Ae. aegypti breeding in plastic containers of water for 8 weeks; at 10 p.p.m. spinosad prevented breeding for > 22 weeks. In another field trial, spinosad at 5 p.p.m. and temephos both completely eliminated reproduction of Ae. aegypti for 13 weeks. In contrast, the bacterial insecticide Bacillus thuringiensis var. israelensis ( Bti , Vectobac ® AS) performed poorly with just 2 weeks of complete inhibition of Ae. aegypti breeding. Spinosad also effectively prevented breeding of Culex mosquitoes and chironomids in both trials to a degree similar to that of temephos. We conclude that spinosad merits evaluation as a replacement for organophosphate or Bti treatment of domestic water tanks in Mesoamerica. We also predict that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.