Über die Ergebnisse der im Schwarzwald 1958 und 1959 durchgeführten Freilandversuche zur Anlockung von Borkenkäfern mit Lockstoffen

Abstract

Summary In the high Black Forest, fallen and standing spruces with crown break were sprayed with a mixture of the methyl esters of the linseed oil fatty acids, to act as traps. In both years, they were strongly attacked by Ips typographus whilst untreated trees remained almost unattacked. The great superiority of the treated trees as traps was particularly evident in early summer with the lower air temperatures. In high summer, the flying in of beetles (2nd generation) evened itself out on treated and untreated trunks. Standing spruces with crown break were strongly attacked by Hylurgops glabratus after treatment with the attractant. Our results show that the treatment of trap trees in early spring can considerably raise their effectiveness. This can be particularly important in connection with the dangerous flying in of beetles in spring and early summer in upland areas where the air temperature is still low.