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Pheromone-dispensing puffers, around for a decade, have an extensive reach in California where they are used for mating disruption in a variety of tree fruit crops. Though usage in the Pacific Northwest has lagged behind, it now is growing, fueled in part by the technology’s labor-savings potential.

During the International Fruit Tree Association’s field tours held recently in California’s San Joaquin Valley, it was observed that puffers were commonly used by apple growers, perhaps more so than in other tree-fruit-growing regions. The Puffer CM, manufactured by Suterra for codling moth control, sprays repeated pheromone doses on a 12- or 24-hour schedule from a canister housed in a plastic cabinet. The puffers are strategically located in the orchard, hung on tree branches. One or two puffers per acre are typically used. Suterra makes pheromone in canisters for codling moth, oriental fruit moth, navel orangeworm, and artichoke plume moth.

Suterra representative Hector Absi estimated that the Puffer CM is used in about 40,000 acres of tree crops in California and in 10,000 acres in the Northwest, along with acreage in Michigan, and the East Coast. He attributed California’s higher use to oriental fruit moth, a widespread pest in California’s orchards but one that has responded very well to mating disruption technology.

Dr. Alan Knight, U.S. Department of Agriculture entomologist in Yakima, Washington, began working with the puffer technology in 1998, comparing hand-applied pheromone dispensers for leafrollers with pheromone released from the puffers. Knight’s research led to the current usage pattern for codling moth, one that integrates hand-applied pheromone around the perimeter of an orchard with puffer canisters placed on a grid system inside the orchard.

Lots of people were skeptical about the concept in the beginning, he said, and no wonder. The initial cabinet that housed the canister of pheromone was made for bathrooms and indoor use, not to withstand outdoor weather elements. Malfunction of the spray mechanism was also an issue in the early models.

“Suterra had to innovate and develop the cabinet as they went along,” Absi said, noting that the current version represents the fifth generation of cabinets. The durability of the cabinets has improved through the years as well as the technology. Today, the cabinets are designed to last three years in the orchard, and there is less than a 1 percent failure rate, he said.

Labor savings

Randy Brown of Gebbers Farms in Brewster, Washington, said that Gebbers is expanding their use of the puffers and will have close to 1,500 acres of apples under the puffers this season. Brown has used the puffers in orchards with low to moderate pest pressure and in locations with varying elevation due to hills and draws.

The labor-savings potential is what drew Brown to try out the puffers. “Labor is a big thing,” he said. “If we can get something to work as well as hand-applied pheromones, but with less labor, I’m all for it.”

They are using the puffers at a rate of 1 to 1.5 per acre, following a grid system for placement of puffers inside the orchard, and combining them with hand-applied pheromone around orchard perimeters. In some areas with low pressure, they’ve gone to one puffer for every two acres.

“I’m still working on building up my comfort zone with the puffers,” Brown said. “I’m gaining more confidence with them every year.”

He has several orchards with moderate to high pressure where he will evaluate use of the puffers in the future. Thus far, the technology has worked well, he noted.

“My concern about the product is just from lack of experience,” he said. “It’s about knowing your orchard, terrain, and pest pressures when you switch over.”

Pears

In Medford, Oregon, Loys Hawkins has used puffers for codling moth control in pears at Bear Creek Orchards, Inc., since 2006. Bear Creek Orchards is a sister company to the mail-order fruit giant Harry and David. In the first year, they tried the technology in 250 acres, adding another 900 acres in 2007. This year, puffers will be used in more than 1,400 acres of pears, and, for the first time, they will use puffers to control oriental fruit moth in their peach orchards.

Hawkins, who is responsible for orchard pest control for Bear Creek, has compared the labor savings from hanging one to two puffers per acre to attaching 200 hand-applied pheromone dispensers per acre. She analyzed the time needed during the season to administer three mating disruption products for codling moth Puffer CM, Checkmate CM, and Disrupt CM and observed the following:

Puffer CMï 0.7 hours per acre to administer

Disrupt CMï 1.9 hours per acre to administer

Checkmate CMï 2.2 hours per acre to administer

Using Hawkins’s analysis, in a 40-acre block, paying workers $8.50 per hour, Puffer CM would cost $238 to apply,  ­Disrupt CM would cost $646, and ­Checkmate CM $748. “The labor savings are a real consideration for Bear Creek,” Hawkins said.

Mating disruption dispensers must be applied during bloom, a very busy time for Bear Creek, she said, noting that several orchard activities are going on at the same time, such as peach thinning, heating orchards for frost control, and spraying fungicides for disease control. “It’s hard for us to find additional workers at that time, and it’s hard to pull labor from these other important tasks to work on mating disruption.”

She said it takes six people to hang the puffers in their 1,400 acres. Because the canisters have enough pheromone to last for the entire season, they started hanging them in the trees in early April before biofix so they can spread out the work and get it done with fewer people.

Being able to better manage their work force is a really important aspect, Hawkins said.

This year, they plan try the puffers in an orchard that is particularly windy.

“We tested the puffers for two seasons, and the efficacy has been there for us, so we felt we could expand as we have,” she said. “In our situation, it works.”

Studying puffers

Dr. Alan Knight knew early on in his research that if puffers were to be used in orchards to dispense pheromone for mating disruption, they would have to cost the same as hand-applied dispensers.

“If the puffer was to be an option, we had to find a way to make it competitive,” said Knight, entomologist for the U.S. Department of Agriculture, in Yakima, Washington.

His research eventually led to the current pattern now followed when using puffers for codling moth, a pattern he calls IHELP (integrated high emission low-point). The pattern integrates hand-applied pheromone around the perimeter of an orchard with puffer canisters placed on a grid system inside the orchard. He found that in a 40-acre orchard, by hand-applying Isomate C pheromone ties in a 30-foot band around the perimeter (equivalent to about 4 acres) and using 16 puffers in the remaining 36 acres, the cost could be kept to around $40 per acre, comparable to the cost of hand-applied pheromone dispensers, excluding labor.

The integrated high emission-low point system was based on three things, he said. “It was based on overcoming the downwind effect, making the technology competitive with hand-applied pheromone, and dealing with problematic orchard borders.”

Knight and other researchers have tested the puffer technology under a variety of conditions. They found that in windy sites, pheromone could be lost on the downwind side. “Under windy conditions, it was blowing right through the orchard,” he said, adding that the high emission system compensates for the wind factor. Though some were concerned that the puffers worked only on flat ground, his studies showed they were effective in both flat and hilly terrain.

Washington State University is also studying the puffers, comparing the technology to hand-applied mating disruption techniques. Dr. John Dunley has begun his third year evaluating the puffer technology in apple orchards.

In a Manson, Washington, apple orchard, where ties around the border and internal puffers have been used for two seasons, he has found comparable results to Isomate C hand dispensers used in an adjacent block. He increased the puffer density on the side where pressure is highest, but overall, the puffer density in the block is 1.4 cabinets per acre, Dunley said. The number of puffers used depends on the pest pressure and ­location.

“You do see some phytoxicity in the tree right around the puffer due to the carrier in the pheromone,” Dunley said. “But I see that as a good thing because then you know it’s working.”

He said there was concern about the reliability of the cabinets and pheromone release mechanism in the early years of the product. But during the two years of his study, he’s had only one problem and that was with a puffer at the beginning of the ­season when they were first putting them up in the trees.

Dunley sees opportunities in the future to use additional technology with the puffer system, as wireless and sensing technologies evolve. He envisions being able to link puffers to weather stations, enabling them to be turned off when weather is too cold for pest activity, and using sensing technology to read how much pheromone remains in the canister.

Suterra, registrant of the puffer device, now uses Global Positioning Systems to map grower orchards and determine placement of the puffers. Map coordinates are provided to the grower to show exactly where to hang the puffers. A site visit from a company representative groundproofs the maps to make sure that there aren’t any hidden barriers (wind or other situations) that require special consideration or compensation.

Pushing the limit

University of California’s Dr. Stephen Welter, entomologist based at the Berkeley campus, worked with mating disruption in pears for many years. Historically, Lake County has been a strong puffer user, with growers in the Sacramento-San Joaquin Delta less so.

Welter is now studying a puffer program in walnuts, pushing the limit of pheromone dispersion by using one puffer per two acres. (Suterra recommends one puffer per acre for codling moth control.) “The program is being driven by economics,” Welter said, adding that walnuts are tall, making coverage difficult, but that they can tolerate higher codling moth pressure than apples or pears.

“I’m not pushing one per two acres in pears at all, but it is working in walnuts, and almonds are starting to use puffers to control navel orangeworm,” he said. “The reality is that there are a lot of parallels between commodities, and we can learn different things from different commodities. The puffer technology is getting more ­sophisticated and interesting. I’m glad we came back to it�at least in the walnuts.”