FIRST RECORD OF Xanthopastis timais IN AMARYLLIS AND EFFECT OF SOURSOP EXTRACT ON LARVAL MORTALITY

Abstract

-The aim of this study was to report the occurrence of Xanthopastis timais (Cramer, 1780) (Lepidoptera: Noctuidae) in amaryllis (Hippeastrum hybridum Hort., Amaryllidaceae), as well as estimating lethal concentrations (LC 50 and LC 99 ) of soursop seed extract, Annona muricata L. (Annonaceae), against its larvae. The experiment was carried out at the Laboratory of Entomology of the Research Center for Agricultural Sciences, Federal University of Alagoas, in Rio Largo-AL, Brazil. First, we collected caterpillars from amaryllis plants that were reared until pupal and adult stages (parental generation). Next, part of the adults was used for species identification, and the rest were bred to produce next generation (F1), being after that applied in a laboratory bioassay. The lab trial was performed in a completely randomized design, with six treatments and five replications containing three second-instar caterpillars. These larvae were fed pieces of amaryllis leaf (4 x 4 cm), which were previously soaked in treatments for 30 seconds and, air-dried on absorbent papers for one hour. Each treatment consisted of one concentration of ethanol extract of soursop seeds (0.0, 1.0, 0.5, 0.25, 0.125 and 0.0625% w/ v) with distilled water and DMSO at 1% (v/ v), for solutions. We noted that the lethal concentrations LC 50 and LC 99 were 0.29% (w/ v) and 2.27% (w/ v), respectively. In view of our results, we can state that larval stage of X. timais were influenced by extract application in terms of survival, mortality, larvae weight and larval stage length. Besides of that, it was the first time this species was recorded in Alagoas state.Keywords: Amaryllidaceae. Annona muricata. Floriculture. Spanish moth. Seeds. REGISTRO DE Xanthopastis timais EM AMARÍLIS E EFEITO DO EXTRATO DE GRAVIOLA NA MORTALIDADE LARVALRESUMO -O objetivo deste trabalho foi relatar a ocorrência em Alagoas da espécie Xanthopastis timais (Cramer, 1780) (Lepidoptera: Noctuidae) em amarílis (Hippeastrum hybridum Hort., Amaryllidaceae) e avaliar o uso do extrato de sementes de graviola, Annona muricata L. (Annonaceae), estimando as concentrações letais (CL 50 e CL 99 ) para as lagartas, bem como os efeitos na fase larval. O experimento foi conduzido no Laboratório de Entomologia do Centro de Ciências Agrárias da Universidade Federal de Alagoas em Rio Largo-AL. Foram coletadas lagartas em plantas de amarílis que foram criadas em folhas dessa planta, até a obtenção de pupas e de adultos (geração parental). Parte dos adultos foi usada para identificação específica, e outros, deram continuidade à geração seguinte (F1), que foi utilizada no bioensaio. O delineamento experimental foi inteiramente casualizado, constituído por seis tratamentos e cinco repetições com três lagartas de segundo ínstar por repetição. As lagartas foram alimentadas com porções de folhas de amarílis (4 x 4 cm), anteriormente imersas em seus devidos tratamentos durante 30 segundos e secas ao ar sobre papel absorvente durante uma hora. Os tratamentos foram: extrato etanólico de sementes d...