Efficacy of endophytic colonization of Beauveria bassiana for the control of Phytophthora infestans on potato

Entomopathogenic fungi, of which Beauveria bassiana is a member, are known as antagonists of insects with multiple functional and ecological roles and are of increasing interest as biocontrol agents in integrated pest management programs. In recent years, there are many studies reporting that B. bassiana provides significant control against some plant disease pathogens with its endophytic ability as well as its entomopathogenic feature. However, very limited information is available about this observed effect of the agent on the pathogen and its possible mechanism in the host plant. This study was carried out to determine the control possibilities of 13_A2, 34_A1 and 37_A2 clonal lineages of Phytophthora infestans, which cause late blight in potato, by endophytic colonization of B. bassiana. Three and seven days after the application of B. bassiana to plants with 4-6 leaves, clonal lineages of P. infestans were inoculated into the plants in the experiments. When the treatments were compared, the disease severity in plants treated with B. bassiana was reduced by up to 60%, especially in the clonal lineages 37_A2 and 34_A1. The results indicate that various defense mechanisms are activated in the plant after the endophytic colonization of B. bassiana. Therefore, the use of an entomopathogenic fungus such as B. bassiana as an endophyte has the potential to reduce pesticide applications in potato production as well as to create an alternative and sustainable plant protection strategy.