INSECTICIDE POTENTIAL OF MICROENCAPSULATED FORMULATION OF Annona muricata (ANNONACEAE) ON Plutella xylostella L. (LEPIDOPTERA: PLUTELLIDAE)

Abstract

The present work aimed to test the insecticidal potential of a microencapsulated formulation of the ethanolic extract of Annona muricata (soursop) seeds on Plutella xylostella. For the estimation of LC50 and LC95, pre-tests were performed with ethanolic extract and microencapsulated in different concentrations to determine Upper Limit (LS) and Lower Limit (LI). The concentrations tested were obtained by the formula of BLISS (1934). Cabbage leaf disks were made and sprayed with the extract solution and the microencapsulated solution at different concentrations using Potter tower (POTTER, 1952). The treated discs were left to dry on a paper towel surface. First instar larvae were deposited on the discs and placed in petri dishes kept in the laboratory. Three days after the bioassay was assembled, mortality was evaluated. The experiment was in a completely randomized design with six concentrations for the extract and six for the microencapsulated solution. In addition, the commercial products AZAMAX® and ANOSON® were tested at their recommended doses. For each treatment five repetitions were used and each repetition with ten larvae. Data were subjected to Probit analysis using the SAS statistical program to estimate CL. A. muricata extract had estimated LC50 and LC95 only 2.04 mL/L and 21.45 mL/L, respectively. By contrast, the microencapsulated extract presented LC50 of 2.34 g/L and LC95 of 67.15 g/L. Azamax® (positive control) at the indicated commercial dosage of 200 mL/100L caused mortality of 66% of the larvae. ANOSOM® caused mortality of only 50% when the recommended dose of 2mL/L was used. Therefore, it is feasible to consider the soursop seed microencapsulated formulation as an efficient alternative for the control of P. xylostella.