Mating disruption of Plodia interpunctella in small-scale plots: effects of pheromone blend, emission rates, and population density.

An indoor mating disruption experiment was performed on the stored-product pest Plodia interpunctella. The female of this species emits a four-component pheromone blend consisting of Z9,E12-14 : OAc, Z9,E12-14 : OH, Z9,E12-14 : Ald, and Z9-14 : OAc. Mating of Plodia interpunctella was disrupted up to 93% by using synthetic pheromone in small-scale plot experiments. The study was performed in 2.5 m x 2.5 m x 2.5 m polythene cubicles housed in a greenhouse, and pheromones were released by MSTRS spraying every 15 min. The disruption effect was tested at different doses 0.075, 0.75, and 3.75 mg/spray (corresponding to 5, 50, and 250 microg/min), different pheromone formulas (one-component (Z9,E12-14 : OAc) and four-component), and at different population densities (10, 20, and 30 individuals, equivalent to 0.32, 0.64, and 0.96 individuals/m2). The moths were released into the cubicles and recaptured 24 hr later. The females were checked for spermatophore presence indicating successful mating. The mating was significantly suppressed in all treatments compared to the control. There was, however, no difference in mating activity between the one-component and four-component disruptants. In addition, EAG measurements were conducted with a portable device to keep track of aerial concentrations of pheromone. The results show that the one-component formula disrupts mating as efficiently as the more complete four-component blend at doses applied in this study. This fact improves the prospects for mating disruption of indoor pyralids, since many pyralid species share the major component in their pheromones, and, thus, can probably be controlled simultaneously by using this compound only.