Entomopathogenic Fungal Endophytes from Pinus Sylvestris Needles and their Potential in Controlling Diprion Pini

Abstract

Entomopathogenic fungi (EPFs) are important factors in the biological control of many insect pests, and these microorganisms often cause widespread epizootics in pest populations. In addition to the use of EPFs as microbial control agents, recent studies show that these fungi can live endophytically with plants. These endophytes are also known to play a role in plants to protect them against insects, pathogens, and nematodes. In this study, it was aimed to isolate and molecularly characterize endophytic entomopathogenic fungi from yellow pine forests in Kırşehir province, Türkiye, and test them against Diprion pini L. (Hymenoptera: Diprionidae). Endophytic entomopathogenic fungus isolation was carried out using a selective medium from a total of 234 healthy needle samples (three from each branch) from 117 branches (two from each tree) from 39 yellow pine trees. After the isolation studies, a total of 24 fungi (10.25% based on the needle number) were isolated and purified. The isolated fungi were then characterized by gene sequencing (Bloc gene for Beauveria spp. and β-tubulin for Metarhizium spp.) and phylogenetic analysis. Twenty isolates were identified as B. bassiana, and four isolates were identified Metarhizium majus. All isolates were also tested against D. pini larvae, and different mortalities were recorded. The highest mortality values were obtained from Beauveria bassiana AD-9, AD-12, and AD-16 with 96.66, 76.66, and 96.66%, respectively. The highest mycoses were obtained from B. bassiana AD-9 and AD-16 with 96.66 and 90%, respectively. These results should be beneficial and provide new opportunities in the control of pine pests using endophytic entomopathogenic fungi.