Potencial inseticida de extratos orgânicos do algodão de seda, Calotropis procera, sobre adultos da mosca do mediterrâneo, Ceratitis capitata

Abstract

The objective of this work was to evaluate the bioactivity of organic extracts obtained from leaves of Calotropis procera, on adults of Ceratitis capitata. To obtain the crude extract, dry cottonseed powder from the silk cotton was subjected to extraction by static maceration with solvent methanol (MeOH). The extract was divided into two aliquots of the same mass, one for bioassays and the other was subjected to successive washes with solvent of different polarities, using, in this order, hexane (Hex), ethyl acetate (AcOEt) and methanol, obtaining thus, three fractions: hexane, ethyl acetate and methanol. All materials were used in toxicity tests, and due to the higher yield, the crude extract and the methanolic fraction were used in the bioassays. For the tests, couples of C. capitata newly emerged in adapted cages were individualized. For each couple, a mixture of food attractant (BioControle® at 5%) and plant material, at concentrations of 12.5%; 25.0%; 37.5% and 50.0% (w / w). The control was composed of 1% tween 80 solution and 5% hydrolyzed protein. To assess toxicity the mortality recorded for 72 hours every 24 hours after exposure. In the bioassays were evaluated the mortality, the longevity of the females, the period of pre-oviposition, the period of oviposition, fecundity and fertility. The experiments were delineated in ICD, with 30 replicates and the results submitted to Kruskal-Wallis analysis and regression by software R-3.5. There were no deaths in the toxicity test for any of the evaluated materials. The crude methanolic extract affected the period of pre-oviposition and fertility. Lower larval hatching was observed at 50% concentration and the pre-oviposition period increased at the 37.5% concentration of the extract. The longevity, oviposition period and fertility were not affected by the crude extract. The methanolic fraction of C. procera, with the exception of mortality, affected all the variables analyzed, causing a reduction in longevity at concentrations of 25%, 37.5% and 50%, and at the 25% concentration caused an increase in the pre-oviposition period. For fertility, the methanolic fraction caused a greater reduction in concentrations of 25%, 37.5% and 50%. Already, the fertility was affected in all the concentrations.