Invasions by alien pathogens are a major threat to forest conservation. The North American fungal pathogen of conifers Heterobasidion irregulare , inadvertently introduced in Central Italy in the 1940s, has been spreading causing high mortality of Italian stone pine ( Pinus pinea ). While invading newfound niches, H. irregulare has established itself in the current range of the native congener H. annosum . The aims of this stu...

A population genetics approach is used to identify the most likely introduction site and introduction pathway for the North American forest pathogen Heterobasidion irregulare using 101 isolates from six sites in Italy and 34 isolates from five sites in North America. Diversity indices based on sequences from ten loci indicate the highest diversity in Italy is found in Castelfusano/Castelporziano and that diversity progressivel...

It was recently reported that North American (NA) individuals of the forest pathogen Heterobasidion annosum were found in a single pine stand near Rome, in association with the movement of US troops during World War II. Here, we report on some aspects of the invasion biology of this pathogen in Italian coastal pinewoods, and on its interaction with native (EU) Heterobasidion populations. Spores of Heterobasidion were sampled u...