Aerosol pheromone dispensers worked as well or better than hand-applied mating disruption dispensers in suppressing codling moth, according to Washington State University research.
“Growers have more robust options today in controlling codling moth than in the past,” said Dr. Jay Brunner, WSU entomologist who compared aerosol pheromone dispensers, also called puffers, to hand-applied dispensers.
The first pheromone dispenser for codling moth, Isomate C, was registered in 1991. The revolutionary pest control method allowed tree fruit growers to significantly reduce codling moth pesticide application. The technique, which works by inundating an orchard with female pheromone to confuse male moths, has been widely adopted by Pacific Northwest apple growers. Brunner estimated that 90 percent of
Washington’s apple acreage is treated with pheromone mating disruption.
The aerosol technology, developed in the late 1990s, works by spraying repeated pheromone doses over a 12- or 24-hour schedule from an aerosol canister housed in a plastic cabinet.
The aerosol application, boasting labor savings of up to 70 percent compared with hand-applied dispensers, was first adopted in California’s walnut orchards. Later, other tree fruit growers in California began using the puffers, primarily because they were well suited for oriental fruit moth.
U.S. Department of Agriculture’s Dr. Alan Knight began working with puffer technology in 1998 (See: “Puffers save labor,” June 2008). His research led to the current usage pattern that integrates canisters in a gridsystem inside the orchard with hand-applied pheromone dispensers placed around the perimeter.
“The hand-applied dispensers worked well—and still do—in Washington orchards,” Brunner said in an e-mail to Good Fruit Grower.
But through the years, researchers, including Brunner, have looked at ways to reduce labor costs involved in applying 200 to 300 dispensers per acre. They studied everything from fibers to flakes laced with pheromone that could be delivered by orchard sprayer; however, such methods didn’t pan out. Eventually, Brunner would spend three years testing aerosol canisters.
Brunner was skeptical of the aerosol technology, even though information from California showed it worked in walnuts for codling moth.
In walnuts, control is not as critical as in apples, he said, adding that damage levels tolerated in walnuts were higher than acceptable levels in apples.
Several years ago, Brunner had access to sterile codling moths from Canada, an important component of the aerosol study. Washington growers have done such a good job with mating disruption that codling moth populations in the state are generally low, making codling moth research very challenging if native populations are used.
In testing the puffer technology under commercial Washington orchard conditions, Brunner evaluated the efficacy of the two types of canisters on the market. Suterra makes CheckMate Puffer, an aerosol canister for control of codling moth and other pests. Pacific Biocontrol is the registrant for IsomateCM Mist. Both work similarly, emitting a mist of pheromone that can be programmed for every 15 minutes or 30 minutes for 12 hours. The reusable cabinets last for several years. One canister lasts a season.
Brunner found that one canister per acre worked as well as 200 to 300 hand-applied dispensers per acre. The aerosol can lasted all season as promised. Canisters should be hung at the same height as the hand dispensers—in the upper third of the tree, about two feet down from the tree top.
“The puffer technology does require a border treatment,” he shared during the Washington State Horticultural Association’s annual meeting. “There will be a gap in coverage on the borders where there is vulnerability.” He defines the border as the outside four to five rows.
He also found some phytoxicity from the aerosol canisters on foliage and fruit resulting from the technical pheromone. “It doesn’t amount to much, about 100 fruit per canister.” Damage, which looks similar to solvent burn from emulsified oils, could be reduced if less pheromone was used.
Brunner collaborated with Michigan State University’s Dr. Larry Gut in studying lower rates of the pheromone in both the mist puffers and hand-applied dispensers to see if lower rates reduced codling moth control.
“Reducing the pheromone rate by 50 percent had little impact on control, so there is some possibility that lower rates could be used,” he said. “But below 50 percent, there was some concern, even if you increased the number of emitters per acre.”
He also looked at reducing the number of hours the canister was programmed, going from 12 hours to 7, but did not find any advantage in having the canister release for less than 12 hours. Codling moth generally flies from dusk to dawn.
Brunner noted that aerosol pheromone technology is limited to larger orchards of 40 acres or more because of the border treatments.
“The results were surprising to me,” he admitted, “but should be good for growers who can use another tool to control their key pest.” •
The original photo caption published with this story online and in the March 1, 2014 issue was in error. While pheromone canisters last all season, the Isomate CM Mist cabinet, made by Pacific Biocontrol, is designed to be used for only one season, not several seasons as was incorrectly stated. According to Suterra’s website, cabinets for CheckMate Puffer are reusable for many years. The caption error above has been corrected.
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