Journal of the American Mosquito Control Association (2005) 21, 446-450

M.M. Stevens, S. Helliwell and P.A. Hughes (2005)
Toxicity of Bacillus thuringiensis var. israelensis formulations, spinosad, and selected synthetic insecticides to Chironomus tepperi larvae
Journal of the American Mosquito Control Association 21 (4), 446-450
Abstract: Three Bacillus thuringiensis var. israelensis (BTi) formulations, the bacterial metabolite spinosad, and 7 synthetic insecticides were bioassayed against 4th instars of Chironomus tepperi, a serious pest of rice in southern Australia. The BTi formulations returned 48-h product median lethal concentration (LC₅₀) values (25 ± 1°C) of between 0.59 mg/liter (VectoBac® water-dispersible granule [WDG], 3,000 international toxic units [ITU]/mg) and 2.15 mg/liter (Teknar® suspension concentrate [SC], 1,200 ITU/mg). When LC₅₀ values were adjusted to reflect nominal ITU values of the 3 products, there was still substantial variation, with LC₅₀ values ranging from 1,770 ITU/liter (VectoBac WDG) to 2,580 ITU/liter (Teknar SC). Aquabac® SC (1,200 ITU/mg) showed intermediate activity. Differential activity between formulations may reflect faster settling rates in the more active formulations, which may be a beneficial characteristic when controlling benthic species such as C. tepperi. Spinosad (24-h LC₅₀ = 28.9 µg active ingredient [AI]/liter) and the synthetic insecticides we evaluated were all substantially more active than BTi. The highest activity was shown by the neonicotinoid compounds thiacloprid, acetamiprid, and clothianidin, which all returned 24-h LC₅₀ values between 1 and 3 µg AI/liter. Indoxacarb and thiomethoxam showed the lowest activity of the synthetic compounds evaluated.
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Link to article at publishers website
Database assignments for author(s): Mark M. Stevens

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Chironomus tepperi	Rice (Oryza)	Australia (South+SE)
Bacillus thuringiensis var. israelensis (entomopathogen)	Chironomus tepperi	Rice (Oryza)	Australia (South+SE)