Biological control of Heterobasidion annosum on Pinus pinea by Phlebiopsis gigantea

The efficacy of a native isolate of Phlebiopsis gigantea in protecting the stumps of Pinus pinea against spore infection by Heterobasidion annosum s.str. was investigated. In preliminary tests carried out in stem pieces of P. pinea in confined environment, the efficacy of the isolate was compared with Rotstop^®, the commercial formulation prepared from a north European P. gigantea strain. Both showed a fully protective effect against artificial inoculation of H. annosum. Moreover, in stump treatment experiments carried out in a coastal P. pinea forest close to Rome, the native P. gigantea was effective against heavy airborne inoculum of H. annosum. Some natural infection by P. gigantea occurred in the stumps, but it was unable to control the pathogen. Random amplified microsatellite analysis allowed to recognize the presence of different P. gigantea strains in the forest.