Endophytic colonization of Eucalyptus by Beauveria bassiana and Metarhizium anisopliae and their effects on plant growth
Abstract Entomopathogenic fungi are effective biological control agents for pest management, also demonstrating several benefits to host plants when acting as endophytes. These fungi benefit from the host’s nutrition and protection, while plants gain greater resistance to herbivores, pathogens, and other biotic stresses. This study evaluated one isolate each of Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin for their endophytic colonization ability and growth-promotion effects in Eucalyptus L’Hér plants. Two methods of artificial inoculation, stem injection and foliar spraying, were used for both fungal species and performed at 0, 15, 30, and 45 days after inoculation. Both fungal isolates successfully colonized Eucalyptus tissues during all evaluated periods. The colonized Eucalyptus plants showed increased number of leaves and branches after endophytic colonization by B. bassiana. M. anisopliae had a higher colonization rate when inoculated by both methods (stem injection and foliar spraying). The positive effects of endophytic colonization on plant growth are associated with the production of bioactive metabolites by the species, via mechanisms that are not yet fully understood. Endophytic isolates offer strategies that may contribute to pest management in Eucalyptus plantations.