Relationships between nutrition and heart rot attack of Norway spruce (Picca abies Karst.) and the fungistatic effect of its inner bark.

The fresh inner bark of Norway spruce sterns and roots inhibits mycelium growth of Fames annosus on malt agar. Nearly all fungistatic substances of the inner bark can be extracted with chloroform and acetone. The acetone-soluble fraction, which amounts to 13-27% of bark dry matter, was analysed. Up to now 12 phenolic substances have been identified, 5 of them have proved to inhibit Fomes annosus in vitro. Open-air-experiments showed, that desiccation of the root-zone, manganese deficiency and nitrogen hypertrophy decrease the inhibitory effect of the inner bark as well as its content of fungistatic substances. The degree of heart rot attack in older spruce stands was found to be negatively correlated with the N-, Fe- and Mn-concentrations in needles.