Resumo

DELGADO BARRETO, Erika et al. Entomotoxic properties of plant extracts of Azadirachta indica, Piper auritum and Petiveria alliacea for the control of Spodoptera exigua Hübner. Rev. Chapingo Ser.Hortic [online]. 2012, vol.18, n.1, pp.55-69. ISSN 2007-4034.

The purpose of this study was to evaluate the antifeedant effect and toxicity of Azadirachta indica, Piper auritum and Petiveria alliacea extracts on Spodoptera exigua larvae under laboratory conditions and in an open-field crop of organically-grown grape tomatoes var. Santa. The work was carried out with hexane and methanol extracts of A. indica seeds and P. auritum and P. alliacea leaves applied in different concentrations against 4^th-stage S. exigua larvae. The variables evaluated were feeding deterrence index (FDI), feeding suppression index (FSI), mortality rate and LC₅₀. The strongest feeding deterrent effect was found in the methanol extract of Azadirachta indica, followed in descending order by that of P. auritum and P. alliacea. The mortality rates for A. indica, P. auritum and P. alliacea were 38.88, 28.8 and 21.22 %, respectively, under laboratory conditions; the same trend was found in the field. The LC₅₀ showed that the methanol extract of A. indica was the most potent (4.03 ppm), followed in effectiveness by that of P. auritum (42.08 ppm). In the field, the LC₅₀ of the methanol extracts of A. indica, P. auritum and P. alliaceae were 9.61, 21.21 and 104.1 ppm, respectively.

Palavras-chave : Azadirachta indica; feeding deterrence; extracts; Piper auritum; Petiveria alliacea; toxicity.