Pest Risk Analysis for Thousand cankers disease (Geosmithia morbida and Pityophthorus juglandis)

Abstract

Thousand cankers disease (TCD) is caused by the fungus Geosmithia morbida in association with the bark beetle Pityophthorus juglandis. In the USA, widespread dieback and mortality of Juglans nigra (black walnut) has occurred since the mid-1990s. The cause of the disease was determined only in 2008, as the combination of feeding damage by P. juglandis and canker development by G. morbida. G. morbida and P. juglandis are spreading in the USA, and the disease has caused extensive mortality on J. nigra and other Juglans species. In 2013, P. juglandis and G. morbida were detected in the EPPO region for the first time in Italy (Veneto region) on J. nigra, and was also detected in 2014 in the same region on J. regia. Thousand cankers disease was added to the EPPO Alert List of pests possibly presenting a risk to the EPPO region in January 2014.