Toxicidade de extratos de lonchocarpus floribundus benth. (timbó) sobre Toxoptera citricidus kirkaldy (pulgão preto do citros) (Sternorrhyncha: aphididae)

Abstract

The use of toxic plants is an alternative for pest control and among them, timbó (Lonchocarpus sp. and Derris sp.) is distinguished, as a common plant in the Amazon region, that possesss the active compound rotenona. This work had as main objective to investigate the insecticidal potential of Lonchocarpus floribundus Benth. (timbó) on Toxoptera citricidus Kirkaldy (black citrus aphid). This aphid attacks the citrus withering of young leaf and killing the sprouts, besides transmitting citrus tristeza closterovirus (CTV). In laboratory, aqueous and ethanolic extracts were obtained, diluted in water in five concentrations (5mg/ml, 10mg/ml, 20mg/ml, 30mg/ml and 40mg/ml). Two bioensays were carried out with different applications of the extract (spraying and translaminar aplications). The experimental design was completely randon in a 2 x 5 factorial scheme with treatments (including the witness) and 5 replicates. Based on the observed results the concentrations 30 and 40 mg/ml , showed the highest mortality of Toxoptera citricidus, for both extracts (ethanolic and aqueous). Between analyzed extracts the most toxic for T. citricidus is the ethanolic. The control recomendation for ling this insect is 5mg/ml of the ethanolic extract or 10mg/ml of the aqueous extract. Therefore, the use of Lonchocarpus fluribundus is an alternative insecticid for managuig the black citrus aphid.