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 (LC50 and LC99) 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 LC50 and LC99 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.