Pest monitoring is an additional expense but one that pays dividends, orchard pest consultants said during a panel discussion at Washington State University’s Fruit School this winter.
Consultant Torrey Hansen, who operates Cascade IPM based in Wenatchee, Washington, said he spends about 70 percent of his work time throughout the summer on monitoring. "It’s definitely the backbone of the service I provide. I don’t understand how anyone can operate without a monitoring program in place."
Dave Gleason, horticulturist with Kershaw Farms in Yakima, Washington, said that with older pest control products growers were able to spray at prescribed intervals without monitoring pest populations, but the newer pesticides are too expensive for that kind of approach. "You waste a lot of money if you don’t know what’s out there," he said. "It’s an extra responsibility and an extra expense, but I think a good monitoring program will save the cost in reduced sprays."
Panelists said they recruit the help of orchard workers to stay informed about pest problems. "I’ve always tried to train people I work with to be aware of what’s going on," Gleason said. "It’s impossible for one person to see every tree and know what’s going on in your orchard."
Most field horticulturists are in a hurry, and people tend to be creatures of habit, always taking the same route through the orchard, he noted. It takes a real effort to look in different parts of the block. Gleason trains tractor drivers and irrigators to look up in the trees once in a while and let him know if they see a problem so it can be addressed before it gets worse. "If you don’t find it early, you can have very significant damage when you get around to picking the block," he said.
As an incentive, he offers McDonald’s coupons to any orchard worker who finds a "worm." The first year he did that, the workers quickly learned to identify both codling moths and leafrollers, and he gave out a couple of hundred dollars worth of coupons. "It really motivated people to be more aware," he said.
Marty Robinson, branch manager with Wilbur-Ellis Company in Brewster, Washington, said it’s not possible for a person to be in every corner of every orchard every week. He’s found orchard workers eager to learn and he can rely on them to tell him when they find pest problems.
Travis Schoenwald, an orchard manager with Gebbers Farms in Brewster, suggests giving crew members or crew bosses a "pest of the day" to look out for as they’re working in the orchard. "Get as many eyes out there as you can," he advised.
Dain Craver, with DAC Consulting in Royal City, Washington, who is both a grower and consultant, said he offers workers $5 in cash for every codling moth sting they find.
About ten years ago, he began training some of the crew bosses how to look for pests, as well as anything else that looked abnormal, such as fruit size. He employs some of his orchard workers after hours to scout in the orchards where he consults. He pays them $15 to $20 an hour and said the employees like both the work and the extra cash.
"I think it’s imperative for everyone to train the people because that’s just going to make you more money in the long run to have more people’s eyes out there looking," he said.
It’s not necessarily the orchard manager who has the greatest talent for scouting, Craver stressed. He has one employee who can find leafrollers when no one else can, while another is a "pear psylla machine."
Craver said chemical company representatives appreciate the scouting help from orchard employees, and Robinson said it’s also helpful if the grower has his or her own trapping program, ideally with a trap in every 2.5 acres of the orchard. Hansen stressed the importance of having enough traps in the orchard. He prefers the white delta trap to the red trap, which attracts flies as well as orchard pests. He’s switching to combination lures, which contain both the codling moth pheromone that attracts males and a kairomone that attracts both males and females. The combo lure is less likely than traditional traps to give a false negative result (meaning moths are not trapped even though they are in the orchard). It is difficult to know from the trap catch numbers when treatment is necessary, but he expects that treatment thresholds will be determined as more people use the traps.
Craver said he also would use more of the combo lures because of their greater tendency to catch moths.
Panelists were asked to highlight one thing they’ve done that contributed to the success of the pest management program.
Gleason said slowing down the tractor when spraying and increasing the gallonage to ensure better coverage is important when using the newer pesticides, which have to be ingested by the pests. He’s using a tractor speed of 2 miles per hour and 200 gallons of water. "With these materials, you have to have excellent coverage," he said.
Robinson emphasized the importance of good sprayer calibration and slow tractor speed. Growers sometimes resist the idea of slowing down, saying they wouldn’t have time to cover all their acreage, but Robinson said they could buy an additional sprayer within a couple of years with the money they save by driving more slowly and not having insect problems.
Craver said he’ll continue with scouting and in all his organic blocks will release predators earlier than in previous years so they are in the orchard before the pests become a problem.
Schoenwald and Hansen said they would continue to use oil in their cover sprays to avoid having problems with mites and woolly aphids.