Armillaria variability and control
Scion is the leading provider of forest-related knowledge in New Zealand
Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.
From Forest health News No. 21, June 1993.
In January 1990 an Armillaria trial was established in a stand of 5-year-old P. radiata in Cpt 365, Kaingaroa Forest, to develop an understanding of the response of Armillaria root disease to thinning. The trial site was selected in part of the compartment previously stocked in P. nigra felled at age 55 years.
The root collars at or near ground level of all plot trees and thinning slumps have been examined for the present or absence of Armillaria infection and in addition all isolates have been mutually paired and culturally tested.
Cultural testing of Armillaria isolates from infected trees showed all colonies were of different vegetative compatibility suggesting that spores may have played a major role in the dispersal and establishment of the fungus.
Site preparation by stump removal and windrowing, though expensive, provides effective control of both lethal Armillaria during establishment and sub-lethal infection later in the rotation. Treatment at two trial sites in an area with a serious Armillaria problem has reduced losses due to lethal infection by 98 and 80% and reduced sub-lethal infection at age 7 by 88 and 54%. Predicted volume gains extrapolated from this data are in the order of 40-50 m3/ha over a 28-year rotation.
This information is intended for general interest only. It is not intended to be a substitute for specific specialist advice on any matter and should not be relied on for that purpose. Scion will not be liable for any direct, indirect, incidental, special, consequential or exemplary damages, loss of profits, or any other intangible losses that result from using the information provided on this site.
(Scion is the trading name of the New Zealand Forest Research Institute Limited.)