Showing papers by "Rainer Meyhöfer published in 2006"
01 Jan 2006
TL;DR: None of the "Last Call" treatments was able to reduce the damage on the horse chestnut leaves, and the "attract property" of the product used has to be greatly improved in order match the attractivity of virgin females.
Abstract: This study was conducted to test the efficacy of an "attract & kill" product against the horse-chestnut leafminer (Cameraria ohridella). A mix of a pheromone of the targeted species and an insecticide attracts the males and eliminates them after contact. This method only reduces the damage by mining larvae if a large number of males is killed before mating can occur. In 2005 the only product available for a test was "Last Call HCLM". Preliminary experiments with the product suggested a limited efficacy. Only 33% of male horse-chestnut leafminers contacted a droplet of "Last Call" in wind tunnel observations. This result was supported by long-term video observations in the greenhouse. Although there was an increased activity observed near the droplet in comparison to a control, only 47% of the observed males that came close to the droplet made contact. In a parallel running observation in the same greenhouse set up an average of 12% out of 30 males released (replicated four times) were killed by "Last Call", when caged with one droplet of 50 mg. The main component of this study was a semi-field experiment where groups of five, 2 m high, horse chestnut trees were isolated in fine mesh cages in order to control the number of moths released. We varied the amount of "Last Call" (1 droplet - 5 droplets) und moth density (approx. 20 adults - 100 adults). To assess the impact of different treatments on the damage caused by the mining larvae, the total number of leaf mines per tree were counted and compared with the untreated control. The results confirmed the previously assumed lack of control: none of the "Last Call" treatments was able to reduce the damage on the horse chestnut leaves. Irrespective of the number of droplets "Last Call", a low moth density caused on average 150 mines per tree and a high moth density 350 mines. Before a continuing with an "attract & kill" strategy against the horse chestnut leafminer in the field, the "attract property" of the product used has to be greatly improved in order match the attractivity of virgin females.
2 citations
01 Jan 2006
TL;DR: Mating-disruption to control horse-chestnut leafminer: lots of pheromone and little disruption?
Abstract: Mating-disruption to control horse-chestnut leafminer: lots of pheromone and little disruption?
2 citations