Modeling the impact of a sex Pheromone/Kairomone attracticide for management of codling moth (Cydia pomonella)

The pear-derived volatile, ethyl (2E, 4Z)-2,4-decadienoate is a potent, stable, and selective bisexual kairomone for codling moth, Cydia pomonella L. Its discovery creates an unique opportunity to develop monitoring and control tactics targeted for both male and female moths. Here we present a population model that compares the relative effectiveness of a male-only versus a bisexual attracticide. The model tracks daily changes in the population densities of pupae, males, and mated and virgin females using daily survival rates, and natural and insecticide-related mortality for eggs and larvae. The use of sex pheromones for mating disruption is included as a scalar variable affecting mating success. Mating is also influenced by the level of competition between virgin females and the insecticide-laced pheromone point sources (determined by their density and potency). The attractiveness of the kairomone lure is determined by the density and relative attractiveness of individual fruits within the cropping system. The potency (attractiveness and lethality) of the attracticide point sources decline at a constant rate over time. Our modelling results demonstrate that the use of a female attractant greatly improves the effectiveness of the "attract and kill" technique. Our model output is compared with field data collected from apple plots treated with mating disruption and a grid of pheromone/kairomone-baited insecticide-treated stations during 2001. The influence of the seasonal attractiveness of ethyl (2E, 4Z)-2,4-decadienoate for codling moth within walnut, pear, and apple orchard the success of the "attract and kill" approach is discussed.