Principles of population dynamics and control of the Great Spruce Bark Beetle, Ips typographus (L) (Col, Scolytidae)

For the benefit of a better prophylaxis and control the picture of the Great Spruce Bark Beetle, Ips typographus, should be corrected in some points. Contrary to the conception guilty till now Ips typ. is a sole secondary pest which doesn't attack healthy trees. Disposed trees weakly attacked by Ips typ. are hard distinguishable from healthy trees. It seems urgent to be necessary to find out the ''critical resin pressure'' which enables to distinguish between disposed and undisposed trees. The self-cleaning of attacked trees (or groups of trees) by high larval mortality in consequence of competition in case of lacking of disposed trees, represents a further strong argument for the sole secondary status of Ips typ. The antiquated focus theory is still widely held, meaning Ips typ. (in general: insects) to be able to found new focuses by overflying. But there are no proofs for this. All of local outbreaks are self-sufficient. Control measures shouldn't more aim at protecting healthy trees but at giving weakly attacked trees the chance of recovering their health by reducing the density of beetles a) by felling trees strongly attacked (+ eliminating their bark) and b) by using pheromone traps. The reducing quote must be as high as possible in order to avoid compensatory effects. Chemical control measures shouldn't be used as they show less effects on the pest but high side effects on men and ecosystem. Meliorating the soil by using fertilizers can increase the resistance of the trees against Ips typ. But after all only transforming the spruce monocultures into natural mixed wood will solve the bark beetle problem fundamentally.