Research and extension partnership leads to successful pheromone mating disruption for codling moth
by Carolyn Pickel, UC IPM and UC Cooperative Extension; Joyce Strand, UC IPM; Rachel Elkins, UC Cooperative Extension; Joe Grant, UC Cooperative Extension; and Steve Welter, UC Berkeley
Close collaboration between research and extension has been key to the success of IPM programs. As one example, UC IPM sponsored many of the research, application, and demonstration projects that have led to successful codling moth control by pheromone mating disruption (PMD) in California pears and walnuts. In doing the work, scientists often partnered with commodity boards and the USDA. The following timeline shows key events, occurring over four decades, that eventually led to adoption of new IPM methods.
The Situation in Pears: In the 1990s, California pears became infested with Guthion-resistant codling moths, and growers needed a new technique for codling moth control.
The current puffer PMD program in pears has eliminated the need for codling moth sprays, except when the pest flies in from trees that haven’t been cared for. The program monitors PMD effectiveness, using one puffer per acre to account for the lower threshold for damage in pears. Growers can eliminate supplemental codling moth sprays whenever monitoring shows no infestations. Spraying then is necessary only for secondary pests.
The original program was designed to minimize risk to growers by implementing PMD along with a full spray program to reduce codling moth populations. Continuing the full spray program reduced risk to growers, so they were willing to try PMD.
The Situation in Walnuts: Walnut growers were slow to adopt PMD, because there was no way to economically distribute a pheromone in the large canopies of walnut trees.
Growers using the puffer PMD program have eliminated codling moth sprays after only two to three years, but they have to be more attentive to walnut husk fly and aphid monitoring, since codling moth sprays helped keep populations of these pests low.
Growers became interested in using the puffer PMD program in walnuts when demonstrations showed the overall cost of the program was the same as a spray program. Growers initially had been concerned about the logistical issues associated with installing puffers in the large canopies of walnut trees, but demonstrations show the additional cost is very low.
Carolyn Pickel, (530) 822-7515
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