Document Type : Original Article
Author
Department of Pest Control and Environmental Protection; Faculty of Agriculture, Damanhour, Alexandria University, Egypt
Abstract
Contact toxicity assay of chlorpyrifos, profenofos,deltamethrin, lambda-cyhalothrin and spinosad were
tested against three species of arthropod pests; the twospotted spider mite Tetranychus urticae, the oleander aphid Aphis nerii and the green peach aphid Myzus persicae under laboratory conditions. The biological assessment was carried out using a slide-dip technique.
The results of the acaricidal activity showed that lambdacyhalothrin and spinosad caused the highest toxicity against T. urticae with LC50 of 4.88 and 6.72 mg.L-1, respectively, followed by chlorpyrifos, deltamethrin and profenofos (LC50 = 11.44, 12.86 and 16.47 mg.L-1, respectively). Based on the toxicity index values, it is quite clear that the toxicity of lambda-cyhalothrin against T.urticae was 1.3 fold more toxic than spinosad and 2.3 and 2.6 fold more toxic than chlropyrifos and deltamethrin, respectively. The results of the aphicidal activity showed that deltamethrin has a high toxic effect against A. nerii and M. persicae with LC50 of 0.31 and 1.11 mg.L-1, respectively whereas, spinosad was the least toxic one
(LC50 = 22.13 and 30.92 mg.L-1, respectively). Based on the toxicity index, it is apparent that deltamethrin is the most potent compound against A. nerii followed by lambdacyhalothrin, chlorpyrifos, profenofos, and spinosad with toxicity index values of 100, 34.04, 3.95, 3.47 and 1.40 but followed by lambda-cyhalothrin, profenofos, chlorpyrifos and spinosad against M. persicae with toxicity index values of 100, 42.52, 27.61, 9.07 and 3.59, respectively. M. persicae was relatively more tolerant than A. nerii to profenofos,
spinosad, chlorpyrifos, lambda-cyhalothrin and deltamethrin with tolerance level of 0.45, 1.40, 1.56, 2.87
and 3.58, respectively.
Keywords
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