Efficacy of entomophatogenic fungi Beauveria bassiana and Cordyceps sp against Crocidolomia pavonana (FABR.) Lepidoptera: Pyralidae) as possible pest management strategy on pepper multi-cropping plantation

Black and white pepper have been considered as the most important perennial crops in some regions of Indonesia yet it took about 3-5 years before the plant start producing. One of the possible approaches to maintain the income of the farmer in the perennial plantation is multi-cropping with high-value annual crops, such as vegetables. However, many pests of vegetables already showed resistance to the common synthetic pesticide applied on the black pepper plant. Thus, it is necessary to apply another strategy for pest control, by applying entomopathogenic fungi. In this study, bioassays and field efficacy of two local isolates of entomopathogenic fungi (Beauveria bassiana and Cordyceps sp.) against one of the most insecticide-resistant pests, larvae of Crocidolomia pavonana (Fabr.) was conducted. In this study, exposure to 1 x 104 conidia mL−1 to 1 x 107 conidia mL−1 resulted in mean larval mortalities from 23.33 to 100% in two days. The probit analysis showed that the LC50 of B. bassiana was estimated at 4.26 x 104 conidia mL−1 which significantly more toxic than Cordyceps sp. (1.57 x 105 conidia mL−1) although the lethal time was similar. From the field tests, cabbage was sprayed with suspension contained 107 conidia mL−1. Means percent of mortality for all treatments was more than 75% and significantly higher (P < 0.05) than the control (tween 80). Conidia of Cordyceps sp. in palm oil cooking oil offered the most promising result against the C. pavonana.