Castor bean pie on the control of banana weevil borer em bananeira-terra

Objetivou-se avaliar o efeito da torta de mamona sobre a infestacao por Cosmopolites sordidus e o desenvolvimento de mudas de bananeira cultivar Terra. Avaliaram-se diferentes dosagens da torta de mamona (0 g, 12 g, 15 g, 18 g e 24 g) aplicadas a cada dois meses, a partir do plantio em mudas de bananeira dispostas num delineamento inteiramente casualizado, com dez repeticoes. Avaliou-se a evolucao vegetativa das mudas pela altura da planta, pelo diametro do pseudocaule e pelo numero de folhas verdes. Efetuou-se a infestacao das plantas com 25 adultos de C. sordidus em cada muda. Os danos causados foram avaliados por meio da percentagem de galerias no rizoma, numero de adultos vivos e mortos, numero de larvas e numero de pupas. Determinou-se tambem o efeito dos tratamentos sobre o valor de absorbancia relativo ao teor de clorofila nas folhas por meio do uso de um clorofilometro. Observou-se baixa infestacao da broca-do-rizoma nas mudas tratadas com a torta de mamona. O crescimento e a absorbancia foram afetados positivamente pela aplicacao da torta de mamona. Assim, a torta de mamona reduz a populacao de C. sordidus nos rizomas de bananeira cv. Terra, favorece o crescimento das plantas e aumenta o valor de absorbancia. Termos para indexacao: Musa sp., Ricinus communis, manejo organico. The aim of this study was to evaluate the effects of castor bean pie on the infestation by Cosmopolites sordidus and on the development of banana plants cv. Terra. To observe the dose-response relationship, each treatment focused on a different dosage of castor bean pie (0 g, 12 g, 15 g, 18 g, 24 g) applied every two months to the banana plants, starting from the planting date. The experimental design was completely randomized with ten replicates. Plant vegetative growth was evaluated by measuring plant height, pseudostem diameter, and counting alive (or green) leaves. The infestation of plants was undertaken by using 25 adults of C. sordidus per plant. Six months after planting, the percentage of damage caused was scored on rhizomes and the number of adults (alive and died), larvae, and pupae was registered. Absorbance related to the leaf chlorophyll content was also determined by a chorophyllometer. In plants treated with castor bean pie there was a low infestation of the banana weevil borer. Vegetative growth and absorbance were also positively affected by applying castor bean pie. Therefore, castor bean pie reduces C. sordidus population in rhizomes of bananas cv. Terra,