PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Agrocybe parasitica, native heart-rot fungus of hardwoods
Agrocybe parasitica, a native heart rot fungus of hardwoods
From Forest Health News No. 41, April 1995
A number of collections of Agrocybe parasitica, a native fungus, have been collected from elms in Auckland. It occurs on a wide range of both native and introduced hardwood tree species but not on conifers. It is typically considered a heart rot fungus although lan Hood notes that it may invade sapwood as a weak parasite and can fruit on new wood at the margin of an open wound. It is well documented as being associated with the progressive loss of limbs and decline in health of Plagianthus betulinus and Hoheria spp. This decline may occur over a long period of time (up to 30 years), or it may occur reasonably quickly - a 10m Hoheria populnea on Arikikapakapa Golf Course, in Rotorua, had a third of its crown suddenly wilt last Christmas. The week before Easter mushrooms of A. parasitica appeared at the first fork in the trunk, approximately 3m above the ground, and more appeared at ground level in the last week of April. There is no conclusive evidence that A. parasitica caused the dieback, as there is a Nectria sp. that also causes branch dieback in these hosts, but it always appears to be associated with dieback. ( Geoff Ridley )
