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The effects of spinosad insecticide to adults of Apis mellifera, Megachile rotundata and Nomia melanderi (Hymenoptera: Apidae)

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March 21, 2001
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This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Mayer, D. F., Kovács, G., Brett, B. L., & Bisabri, B. L. (2001). The effects of spinosad insecticide to adults of Apis mellifera, Megachile rotundata and Nomia melanderi (Hymenoptera: Apidae). International Journal of Horticultural Science, 7(1), 93-97. https://doi.org/10.31421/IJHS/7/1/257
Abstract

The toxicity of spinosad to adult female bees tended to be least to the honey bee (Apis mellifera L.) (LD50 = 0.078 pg/bee), intermediate to the alkali bee (Nomia melanderi) (0.065 pg/bee), and greatest to the alfalfa leafcutter bee (Megachile rotundata (F.)) (0.058 pg/bee), both in topical drop tests and in tests involving spinosad residues on alfalfa (Medicago sativa) foliage. For the calculated LD50 pg/g, the honey bee (LD50 = 0.612 pg/g) was the most susceptible followed by the alkali bee (0.773 pg/g) and the leafcutter bee (1.908 pg/g). The honey bee oral LD50 was 0.063 pg/bee and the calculated LD50 0.492 pg/g. Adding an adjuvant to spinosad sprays did not change the toxicity of spinosad to bees in residue bioassay studies. Spinosad at as high as 500 ppm in feeders containing a sucrose/honey syrup caused no significant reduction in honey bee visitation or total syrup consumed.