Bioatividade de extratos vegetais sobre Diabrotica speciosa (Germar, 1824) (Coleoptera, Chrysomelidae)

• Autor(a) principal: Seffrin, Rita de Cássia Andrade dos Santos
• Data de Publicação: 2006
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/3182
• topic: Agronomia; Agricultura; Pragas; Controle biológico; Inseticidas; Alelopatia; Bioecologia; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA

In this research, the of Meliaceae species for use as alternative control to Diabrotica speciosa was evaluated. The bioassays were carried out under laboratory condictions to determine: the feeding behavior of this insect on six Meliaceae species; the contact effect of aqueous extracts of unripe fruits of Melia azedarach var. azedarach and antifeedant effect after extract storage; the presence of cyanide in unripe fruits; the insecticide activity of extracts from unripe fruits using the brine shrimp Artemia salina Leach and their toxicity to rats. The efficacy of aqueous extracts from structures of M. azedarach var. azedarach against D. speciosa were evaluated on cucumber (Cucumis sativus) and green-beans (Phaseolus vulgaris) crops under greenhouse conditions. The results allowed to conclude that the feedant preference index is important, but it is also necessary to compare overall consumption to determine the most active extract; aqueous extracts from Cabralea canjerana (Vell.) Mart., Cedrela fissilis Vell., Melia azedarach L.var. azedarach, Trichilia catigua A. Juss., Trichilia claussenii C. DC. and Trichilia elegans A. Juss. were antifeedant to D. speciosa; topical applications of extracts from unripe fruits of M. azedarach var. azedarach (10%) neither kill adult nor alter the feeding behavior in the period of 120 h after use; the extract maintained its antifeedants properties after storage for four days at 10ºC. The polarografic test did not detect cyanide in unripe fruits. The bioactivity test using A. salina did not show toxic activity and the aqueous extracts from unripe fruits prepared at 2,5%, 5% and 10% did not cause death, behavior changes or hepatic and renal toxicity in rats. Unripe fruit extracts from M. azedarach var. azedarach (10%) were the most efficient extract tested at greenhouse conditions on D. speciosa. Extracts of unripe fruits reduced the height, production and number of fruits in Cucumis sativus but not in Phaseolus vulgaris