Natural occurrence of the entomopathogenic fungi Beauveria bassiana as a vertically transmitted endophyte of Pinus radiata and its effect on above- and below-ground insect pests

Abstract

The New Zealand forest industry would greatly benefit from a successful way of controlling insect pests. The entomopathogenic fungus, Beauveria bassiana, could hold such potential. It has previously been shown to be capable of endophytic colonisation of the Monterey pine Pinus radiata. We investigated B. bassiana transmission in P. radiata and whether this fungus, while acting as an endophyte, was beneficial to this tree species by testing its effect on above- and below-ground insect feeders. Beauveria bassiana was detected in P. radiata seedlings which had not previously been exposed to the fungus, indicating a vertical mode of transmission. The presence of the fungus negatively affected the fitness of below-ground insects feeding on the plant by reducing their survival by over 10% and their weight by about 5%. This vertically-transmitted beneficial endophyte of pine could be used cost-effectively to control insect pests in commercially-grown P. radiata plantations.