The naturally derived insecticide spinosad is highly toxic to Aedes and Anopheles mosquito larvae

Abstract

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 (LC50) 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 LC50 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/m3 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.

Management of Tuta absoluta (Lepidoptera, Gelechiidae) with Insecticides on Tomatoes

“…Because of its unique mode of action, involving the postsynaptic nicotinic acetylcholine and Gamma-aminobutyric (GABA) receptors, spinosad has strong insecticidal activity against insects (Salgado, 1998) especially Lepidoptera (e.g. Helicoverpa armigera (Wang et al, 2009), Spodoptera frugiperda (Méndez et al, 2002), Diptera (King and Hennesey 1996;Collier and Vanstynwyk , 2003 ;Bond et al, 2004), some Coleoptera (Elliott et al, 2007) as well as stored grains (Hertlein et al, 2011). To date, spinosad is considered a good alternative control of Lepidopteran pests due to its high activity at low rates and its use in integrated pest management programs.…”

Using the Bio-Insecticide Bacillus Thuringiensis Israelensis in Mosquito Control

“…This mixture exhibits extended residual control and good efficacy in polluted water contrary to Bti. The neuro-toxic spinosad produced by the actinomycete Saccharopolyspora spinosa also exhibits efficient mosquitocidal activity (Bond et al, 2004). Plant compounds are a main source of natural insecticides (Després et al, 2007) and their efficiency has been evaluated against mosquitoes.…”

Fine-scale evolutionary genetic insights into Anopheles gambiae X-chromosome

“…Three of these four genes belong to nicotinic acetylcholine receptor gene families [19] which are the known targets of insecticides, neonicotinoids [20], as well as naturally derived spinisyns [21]. The presence of such high number of introns in these genes shows that they require more variability in their protein products and more number of introns make these genes more versatile in their expression by increasing the chances of alternative splicing and less 5′splice site biasness [22].…”