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Selective Toxicity of Certain Recent Insecticides and Botanical Extracts to Diaeretiella rapae Parasitoid and Its Host, Brevicoryne brassicae

Research Authors
Gamal Abdel-latif M. Abdu-Allah
Research Abstract

Several pesticides from neonicotinoid and spinosyn groups were recently introduced for controlling several insect pests in Egypt. Plant materials contain numerous powerful insecticidal components; these are a promised alternative safe candidate to harmful synthetic insecticides. The neonicotinoids (thiamethoxam, acetamiprid), spinetoram, and botanical extracts (sausage, rosemary, canola) toxicity was tested toward apterous aphids, Brevicoryne brassicae (L.) as well as mommies and parasitoid adults, Diaeretiella rapae (M’Intosh) under controlled laboratory conditions using leaf dip and dry residue film of Potter Tower. The carboxylestrases activities of the two insect species adults were also determined using α-naphthyl acetate (α-NA) by colorimetric technique. Spinetoram revealed aphicidal activity similar to the tested neonicotinoids against cabbage aphid. The insecticides as well as extracts except rosemary were more toxic against mommies than aphids after 24 hrs from dipping exposure. Seven days later, the insecticides and sausage extract treatments were less toxic to parasitoid that emerged from treated mommies compared to aphids. The insecticide and extract treatments except sausage treatments were less toxic in parasitoid adults using dry contact residue film compared to aphids. The caboxylestrase enzymes showed lower affinity in aphids than in parasitoids by 11.66 folds. On contrary, the maximal activity (Vmax) was higher in the aphids than the parasitoid by 2.57 folds. To sum up, thiamethoxam, acetamiprid, spinetoram, sausage extract, and canola extract were higher toxic to parasitoid mommies than aphids after 24 hrs from dipping exposure; these effects were not recognized in the emerged parasitoid adults. The insecticides as well as extracts were less toxic to the parasitoids than aphids using dry residue film. The caboxylestrases should be considered as one limited factor for the selectivity of tested compounds in aphid and their parasitoid.

Research Department
Research Journal
Egyptian Scientific Journal of Pesticides
Research Publisher
www.esjpesticides.org.eg
Research Rank
2
Research Vol
3
Research Website
http://www.esjpesticides.org.eg/VOLUMES
Research Year
2017
Research Pages
1-10