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Factors affecting efficacy of pheromone lures for spruce bark-beetles
Zahradníková, Marie ; Holuša, Jaroslav (advisor) ; Emanuel, Emanuel (referee)
This thesis evaluates the effectiveness of defensive techniques against the spruce bark beetle (Ips typographus L.) with a primary focus on pheromone traps and selected factors affecting their efficacy. The factors tested are the setup system of pheromone traps and type of pheromone dispenser baits, the effect on the efficacy of pheromone traps of increasing evaporated pheromones, a comparison of the biological efficacy of different types of pheromone dispensers and an assessment of their impact on the swarming curve. In addition, an evaluation of non-traditional methods of forest protection against the spruce bark beetle (water spraying of whole landings, efficacy of insecticidal sraying of whole landings, and the use of insecticidal nets) was conducted and the possibility of the spruce bark beetle s sex determination was also examined.
When comparing the systems of pheromone traps installation, (1) the standard way was along the stand edge with 20 m space and (2) traps concentrating in the centre of clear cut adjacent to each other with different baiting, the most effective way was found to be the standard trap arrangement and the system with traps installed in line with the dispenser in each pheromone trap. Efficacy decreased with a lower number of pheromone dispensers. The influence of increased amounts of evaporated pheromone on efficacy was tested. Pheromone traps with one, two or three dispensers were compared and it was found that a trap s efficacy was not increased with a higher amount of released pheromone. The Pheagr IT and IT Ecolure Tubus dispensers showed unchanged effectivity throughout the flight activity of spruce bark beetle, but other dispensers need to be replaced according to the instructions since their efficacy decreases, thus affecting the swarming curve. Trying to determine the sex of the spruce bark beetle by selected morphological parameters shows that the gender can only be reliably determined by an autopsy of genitals.
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