Efficacy of the Key Isolated Entomopathogenic Fungi for the Biocontrol against Tuta absoluta in Tomato Plants

Abstract

The tomato is an important vegetable crop, both domestically and commercially.  Recently, the crop is facing the problem of insect pest destruction, which causes its production to drop by up to 50% if not controlled. Tomato leaf miner, Tuta absoluta (Meyrick) is one of the most destructive insects of tomato. The entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae are currently used as an efficient biological control agent against Tuta absoluta. In this study, the efficacy of entomopathogenic fungi was tested using EPF obtained from 24 soil samples collected from tomato farms infested by T. absoluta. The efficacy of EPF were tested against Tuta absoluta larvae instars, pupa, and adults at different conidial concentrations and incubation times. The results showed that among all EPF, Metarhizium anisopliae had high pathogenicity and recorded a high percentage of Tuta absoluta larval mortality rate (98.2%), followed by Aspergillus spp., which recorded 71%. Other EPF recoded lower percentages, which imply lower pathogenicity. Despite Aspergillus spp. being entomopathogenic fungi that have high pathogenicity for Tuta absoluta, it is not recommended for Tuta absoluta management in tomato production due to aflatoxin, which is very toxic to humans. Based on these observations, Metarhizium anisopliae has the potential to be used as an effective biological control of Tuta absoluta in tomato production.