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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

1983

Abstract

The spruce bark beetle, Ips typographus, infects Norway spruce trees with blue-stain fungi, amongst which several species of Ceratocystis are found. Artificial inoculation of healthy trees with C. polonica caused in several cases increased water stress of the trees, and complete sapwood staining. The defences of spruce against Ips/Ceratocystis attack appear to depend on 1. the output of constitutive resin from severed resin ducts, and 2. accumulation of secondary resin around the attack sites. Our preliminary studies indicate that the amount of both types of resin may vary considerably between trees, as well as from place to place on the same tree. A dose/response experiment based on artificial inoculation of C. polonica indicated that at a certain dose (i.e. number of infections per unit area), the accumulation of secondary resin decreased, and the fungus was able to overcome the host defence.