Effect of isolates of entomopathogenic fungi in the coconut eye borer

Abstract

The objective of this study was to evaluate the effect of entomopathogenic fungi on adults of Rhynchophorus palmarum (Coleoptera: Curculionidae). The experimental design was completely randomized in a factorial design (5x3) + control, composed of five treatments (isolated IBCB 66, CPATC 032, CPATC 057 and T9, and the commercial product Boveril®) and three concentrations of each fungus (107, 108 and 109 conidia.mL-1). The data of confirmed mortality were submitted to analysis of variance (ANOVA) using the Proc ANOVA of SAS, and the means compared by Tukey test at 5% probability. To determine percentage survival, confirmed mortality data were subjected to Log-Rank test using the Kaplan-Meyer method. Subsequently the values of LC50 and LT50 were estimated submitting mortality confirmed the Probit analysis. For the concentration 108 conidia.mL-1, the isolates CPATC 032 and CPATC 057 caused confirmed mortality of 52 and 44% of the adults of R. palmarum, respectively. At the concentration 109 conidia.mL-1, the isolates CPATC 032 and CPATC 057 caused mortality of 64 and 52% of the insects, respectively. For the CPATC 032 isolate, in the three concentrations tested, the insects had an average survival of 11 to 12 days. The TL50 of isolate CPATC 032 at concentrations 108 and 109 conidia.mL-1 was approximately 17 days. All isolates tested and the Boveril® product are pathogenic to R. palmarum.