Induced resistance in the interaction of beech tree (Fagus sylvatica L.) and beech scale (Cryptococcus fagisuga LIND.)

Fagus sylvatica L. and Cryptococcus fagisuga LIND. (Coccina, Pseudococcidae) are subject to an intimate host-parasite relation. In this relation the nutrient-quality of the host is an important factor influencing the fluctuation of the scale. In 1994, 1995 and 1996 the degree of beech scale infestation was recorded on 120 beech trees. Simultaneously, the compounds of the primary and secondary metabolism of the beech bark were analyzed and investigated in a pair comparison. I;or the pair comparison of the bark compounds distribution indices of nutritional value were worked out. Concentration differences of soluble carbohydrates, protein amino acids, and phenolic compounds and differences of indices of nutritional value were determined in the inner and enter bark among the different states of infestation. They were discussed as induced staggered defence reaction.