Armillaria root disease in New Zealand forests

The Armillaria root disease caused by A. novae-zelandiae (Stevenson) Herink and A. limonea (Stevenson) Boesewinkel continues to affect plantation forestry in New Zealand. Although the land area being converted from indigenous forest to pine plantation is declining, limited evidence demonstrates that stands already planted on such sites may harbour non-lethal, chronic infection throughout the rotation, with a consequent reduction in growth yield. There are indications that chronic infection may persist in certain second-rotation stands, although the total area of forest infected by Armillaria species is unknown. Effective control and management of this disease must be based on a sound knowledge of its development during the course of the rotation