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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