Występowanie i szkodliwość choinka szarego (Brachyderes incanus L.; Coleoptera, Curculionidae) dla sosny zwyczajnej (Pinus sylvestris L.)

The aim of this work was to evaluate the occurrence and harmfulness of Brachyderes incanus to young Scots pine (Pinus sylvestris L.) plantations on forest areas burned during the forest fire in 1992. The development of B. incanus outbreak had place 4 to 5 years after fire and was connected with the diminishing of macronutrients content in soil. The population of B. incanus is characterised by fast increasing or decreasing the number of individuals. During two years (two generations), the number of beetles increased from 1−2 individuals/tree (at one observation) to 50−80 individuals/tree. Also during two years, the number of beetles diminished to very low level (lower than one individual/tree at one observation). The outbreak of B. incanus in the mentioned above forest areas had place in 1999−2001.