Spread of Armillaria spp. and Heterobasidion annosum in Norway Spruce Exposed to Drought, Irrigation and Fertilization : Root and Butt Rots

Uppsala

International Union of Forest Research Organizations, Swedish University of Agricultural Sciences

1994

S. 582-591

23 Lit. Ang.

Bandaufführung

13462

73773

The effects of irrigation, drought and various fertilizers were studied by inoculating the bark of 26-year-old Norway spruces, representing two provenances, with Armillaria ostoyae and Armillaria borealis and inoculating the wood with Heterobasidion annosum. Armillaria ostoyae was more successful than Armillaria borealis in infecting the bark. The treatments had no marked effect on the spread of Armillaria ostoyae or Armillaria borealis in the bark/wood layer. However, the spread of Heterobasidion annosum in the wood was greater in irrigated and fertilized trees than in trees exposed to drought or excess nitrogen and sulphur. One provenance was infected more severely by Armillaria ostoyae and less severely by Heterobasidion annosum compared with the other provenance. In the former the Armillaria ostoyae infection process seemed to be favoured by drought stress. Provenance related variation in the response to different abiotic and biotic stress factors is discussed.