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Laboratory and field evaluation of the efficacy of four insecticides for Aedes vigilax (Diptera: Culicidae) and toxicity to the nontarget shrimp Leander tenuicornis (Decapoda: Palaemonidae)
- Brown, M.D., Thomas, D., Mason, P., Greenwood, J.G., Kay, B.H.
- Journal of economic entomology 1999 v.92 no.5 pp. 1045-1051
- Aedes vigilax, Palaemonidae, insecticidal properties, toxicity, temephos, pirimiphos-methyl, methoprene, Bacillus thuringiensis subsp. israelensis, nontarget organisms, field experimentation, pH, turbidity, water quality, water temperature, salinity, bioassays, adverse effects, dissolved oxygen, Queensland
- Laboratory and field evaluations were conducted in southeastern Queensland, Australia, to determine the toxicities of 2 organophosphate compounds (temephos and pirimiphosmethyl), an insect growth regulator (s-methoprene), and Bacillus thuringiensis variety israelensis de Barjac (Bti) to Aedes vigilax (Skuse), an Australian saltmarsh mosquito vector of Ross River virus. The toxicity of these compounds to Leander tenuicornis Say, a cohabiting nontarget shrimp species, was also assessed. s-Methoprene and Bti were found to be the most selective for Ae. vigilax, with selectivity ratios of (LC(95) nontarget/LC(95) target) of 255,000 and 38,000, respectively. In contrast, selectivity ratios of 13 and 0.01 were calculated for temephos and pirimiphos-methyl, respectively. As predicted by the laboratory studies, the field applications of s-methoprene and Bti were highly effective against Ae. vigilax, while not affecting L. tenuicornis survival. In contrast, although temephos and pirimiphos-methyl were both effective against Ae. vigilax, these products also killed 100% of caged L. tenuicornis, s-Methoprene and Bti did not affect water quality, whereas temephos and pirimiphos-methyl significantly influenced pH and turbidity. Accordingly, based on the high selectivity ratios, excellent field efficacy, and lack of influence on abiotic water characteristics, s-methoprene and Bti were ideal for insecticide control of Ae. vigilax in Australian saltmarsh pools.