EPPO Global Database

EPPO Reporting Service no. 08 - 2015 Num. article: 2015/149

Heterobasidion irregulare detected for the first time in Minnesota (US)

The presence of Heterobasidion irregulare (EPPO Alert List) has recently been detected for the first time in Minnesota (US). During a survey conducted in red pine (Pinus resinosa) plantations that had been previously thinned in Southeastern Minnesota, groups of dead and dying trees, occurring in a circular pattern, were observed. Samples were collected from dead and dying trees, and obtained from the main stem at and below ground line and from roots. Laboratory analysis (isolation on growing media, morphological characteristics, PCR, sequencing) confirmed the identity of the fungus. It is concluded that because
P. resinosa is an important tree species in Minnesota covering approximately 270 000 ha (662 000 acres) of forest, management strategies for controlling this disease should be implemented in Minnesota.


Blanchette RA, Held BW, Mollov D, Blake J, d’Amato AW (2015) First report of Heterobasidion irregulare causing root rot and mortality of red pines in Minnesota. Plant Disease 99(7), p 1038.