On the attaction of Ips typographus L. 2. Integration of natural breeding material in control methods by pheromones
1986
Johann, M. (Goettingen Univ. (Germany, F.R.). Inst. fuer Forstzoologie)
Between 1981 and 1983 in the forest districts of Fuerstenberg and Neuhaus (Solling hills) and Lonau (Harz mountains) experiments were performed to increase the effectiveness of pheromone traps against Ips typographus. This was attempted by additional baiting with bark extracts, esters, and logs of spruce (Picea abies) whereby the latter were used partly as independent trap systems. Ethanol extracts have a deterrent effect, ligroin extracts and the esters did not influence the trapping results. As compared to landing traps the attractive effect of the pheromone is increased up to six times by logs of spruce which were well supplied with water. Three weeks old logs with a lower water content had a neutral effect. Artificially dried spruce logs decreased the attractiveness of the pheromone to values between a third and a fifth
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