Redução da Oviposição de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae) em Folhas de Feijoeiro Tratadas com Extratos Botânicos

Eliane D. Quintela e Patrícia V. Pinheiro

Abstract

The effects of botanical extracts on the oviposition of Bemisia tabaci (Genn.) biotype B and the neem oil Azadirachta indica A. Juss persistence on leaves of dry bean Phaseolus vulgaris L. were evaluated. The commercial products of neem, Nimkol-LS (extract of seeds and leaves), Nim-I-Go (oil) and Dalneem (oil), crushed tobacco (Nicotiana tabacum L.), commercial extract from neem leaves, homemade aqueous extracts from neem and rue leaves (Ruta sp.) were tested. The number of eggs laid on bean leaf surface was evaluated after six hours of releasing. To evaluate the persistence of neem on bean leaves, groups of plants sprayed on the adaxial or abaxial surfaces of the leaves with Dalneem at 0, 0.25, 0.5 and 1.0 % (v/v) were offered to adults of whitefly at the same day of spraying and after two and four days. In the second experiment, groups of plants sprayed on the abaxial surfaces of the leaves with Dalneem at 0, 0.5 and 1.0 % (v/v) were offered to the insects at the same day of spraying and after three, five and seven days. All of the products tested reduced the oviposition in relation to the control, excepting the commercial extract from neem leaves. The number of eggs on the leaves reduced with increasing in the concentrations of the products. The neem oil sprayed on abaxial surface of the bean leaves at doses³ 1.0 % can reduce the whitefly oviposition over 80 % by ³ 7 days.

Key words
- Azadirachta indica, Nicotiana tabacum, Ruta sp., persistence, whitefly.

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