On the possibilities of the use of juvenile hormone in wood protection
The annual world-wide extent of losses caused by wood-destroying insects in timber in buildings and timberyards is very difficult to estimate. In general exact values are only known in cases of claims for damages from insurance companies or in litigation. At present the best known wood destroying insects in Switzerland are the house longhorn beetle (Hylotrupes bajulus) and the common furniture beetle (Anobium punctatum). With the increasing imports of tropical timber to Switzerland the risk of bringing unknown pests in exotic timber is growing too. One of these pests is the powder post borer, Lyctus brunneus. Principally it is introduced in the wood species obechi and limba from Central African regions. In most cases the logs are processed here, the damage not being noticed at this stage, and the timber used almost exclusively indoors. Within buildings the beetle Lyctus brunneus finds a climate within its biological tolerance. Consequently its destructive power finds its optimum conditions and the damage caused is often considerable. In Germany Lyctus brunneus takes an important place on the scale of the economic important wood destroyers and it is also spreading in Switzerland. For the selection of the test insect for these investigations the afore-mentioned topicality of the beetle and also some technical advantages in working with the insect are decisive, viz: - short life cycle (only 3 months for each generation) - simple breeding methods - the presence of the necessary information on its mode of life. The following short introduction into the biology of the insect Lyctus brunneus, living in wood, is important for the comprehension of the problems arising by experimenting with JHA (juvenile hormone analogues).