Stump Infection by Heterobasidion annosum and its Control in Stands at the First Thinning Stage

1991

12 S.

6 Abb., 1 Tab., zahlr. Lit. Ang.

Bandaufführung

37282

Air borne infection by Heterobasidion annosum and its control during the first thinning were examined in two Scots pine stands and one Norway spruce stand southern Finland. Water suspensions of Phlebiopsis gigantea (two strains) and 20% urea solution were used. The substances were spread on the surface of the stumps during felling using a stump-spraying device fitted to a chain-saw. A total of 501 pine and 278 spruce stumps were investigated. Heterobasidion annosum had spread to the spruce stand and one of the pine stands prior to the first thinning. H. annosum also infected stumps in these stands after thinning. The other pine stand was uninfected before thinning, and did not become infected after thinning, neither. In the pine stumps treated with P. gigantea no H. annosum infection was detected. However, control of air-borne infection of the spruce stumps by H. annosum was not successful with P. gigantea. Control with urea was successful in no case. Application of P. gigantea was successful with the stump-spraying device. However, the apparatus also sprayed the fungal suspension on the felled timber. The apparatus is not without modifications suitable for spreading of the urea solution.