Mating disruption dispensers work by releasing synthetic pheromone which prevents or delays males from finding females, thus reducing the reproductive rate of the population. Now is the time to decide which dispensers to place in the orchard so you have enough time for ordering and to organize your work force.
Codling moth mating disruption should be considered the foundation of any apple pest management program. When mating disruption products are applied before the first moths emerge, mating is reduced thereby limiting the number of codling moth eggs laid in the orchard. Fewer eggs laid means smaller populations that will need to be controlled with insecticides.
How does mating disruption work?
The female codling moth releases a specific chemical, a pheromone, that attracts the male moth. The male moth can detect extremely small amounts of the this pheromone and will fly to locate the source, the female, in order to mate. Mating disruption dispensers release this same pheromone and, when placed properly in an orchard, inhibit the ability of the male moth to locate and mate with the female. For this tactic to work, hand-applied dispensers must be placed in the upper third of the tree canopy well before the earliest moth emergence. Puffer dispensers should also be placed before the earliest moth emergence in accordance with the instructions supplied by the manufacturer.
How many dispensers should I apply?
Based on data collected from studies with hand-applied dispensers, we recommend that the full rate of any dispenser type be used unless there is a good reason to consider reducing the number of dispensers per acre. Reducing the number of dispensers per acre increases the risk of crop injury or the need for supplemental insecticide sprays. Under a good pheromone-based codling moth control program it is possible to eventually reduce the number of dispensers per acre. Puffers should be applied as instructed by the manufacturer, usually in a grid of 1 puffer/acre with a 30-foot border that has hand-applied dispensers at the full rate.
How long does mating disruption last?
All of the hand-applied dispensing systems that are currently available have been designed to be applied one time per season in Washington conditions. In tests conducted at the Tree Fruit Research Center in Wenatchee, WA, each of these products continued to release pheromone for 140-150 days (mid April until early September) or for the approximate duration of two codling moth generations. In locations where three generations of codling moth are expected, additional control tactics may be required. Puffer dispensing systems are designed to last an entire growing season. Check with the manufacturer to purchase the right sized can for your area.
Implementing a sound monitoring program will help determine if extra controls are necessary. (Jay Brunner, Mike Doerr & Keith Granger, WSU-TFREC)