Blister rusts in China: hosts, pathogens, and management

China has 12 taxa of white pines (subgenus Strobus), including species of wide distribution valuable to plantation forestry and species of rare endemics only distantly related to other white pines. The most important forest diseases of these white pines are caused by the blister rust fungi of the genus Cronartium that alternate to telial host species of Ribes and Pedicularis. The most serious infestations have occurred in southwestern China on Pinus armandii and in northeastern China on P. koraiensis. The blister rust pathogen on P. armandii has usually been identified as Cronartium ribicola. Several lines of evidence, however, imply this pathogen on P. armandii is different from a pathogen on P. koraiensis that appears more closely related to C. ribicola in North America, Europe, and other Asian countries. In China, C. ribicola is designated as a quarantine pest. Silvicultural control of blister rust relies on pruning and thinning infected trees, herbicide removal of telial hosts, and chemical treatment of blister rust cankers. Although plantation forestry is important in China, little information is available on the genetics of resistance in Chinese white pines to native blister rust fungi. Challenges and opportunities are identified in forest management and research for disease assessment and control, rust systematics and biology, and genetic interactions in the white pine blister rust pathosystem.