The future of pest management in pears is bright, thanks to coming technology, Washington State University entomologist Dr. John Dunley believes.
His vision of pear pest management 30 years from now might sound like science fiction, he admitted at the Washington State Horticultural Association’s annual meeting in Wenatchee. However, 30 years ago, when a grower’s arsenal comprised organo–phosphates, carbamate, and pyrethroid insecticides, who would have thought mating disruption would be possible?
Nowadays growers have lots of options for controlling pear pests. Products with eight different modes of action are available to control pear psylla. For codling moth, there are seven modes of action, and for spider mites, there are six.
In the future, insecticides will have an even narrower spectrum, Dunley believes. "We’re already seeing insecticides that are more specific to the pests and have less effect on the natural enemies," he said. "They are much more environmentally friendly than previous ones, and safer."
There might be insecticides that are specific to the cuticle of a specific insect. There might also be insect-specific toxins that will bind to receptors only found in insects. Altacor, a new insecticide that should be available this year, contains the active ingredient rynaxypyr, which binds only to the ryanodine receptors in the muscles of insects and does not affect mammals.
Dunley expects kaolin clay products will still be around in 30 years because pear psylla is unlikely to develop resistance to it. He expects to see more attract-and-kill products, which combine a pheromone and insecticide. Like the spinosad product GF-120, they can be applied from a four-wheeler with a small spray attachment, rather than a full-size sprayer. They might even be applied from bait stations.
The computer will become the center of the orchard, Dunley predicted. As weather stations become cheaper, growers will have stations in different microclimates throughout the orchard that are linked to the computer via wireless networks. Growers will be able to remotely track temperature, wind, leaf wetness, and even light interception, in order to estimate the rate of photosynthesis and predict yields. Weather data will also be used to calculate how long an insecticide will be effective in the orchard.
For insect monitoring, smart traps will automatically send trap data to a centralized computer. Smart traps for codling moth are being developed now. Growers might receive computer alerts recommending they make spot treatments to certain parts of their orchards. Dunley envisions a robotic device, similar to iRobot’s Roomba vacuum cleaner, that would go around the orchard applying –insecticides only where necessary.
Automated farming will work best on an areawide basis, with growers sharing information through a system similar to Napster, where people put some information in and take some out, Dunley envisions.
"You will be able to design programs tailored to the orchard, based on data that not only comes from your orchard but everybody else’s orchard."
Sniffers that can detect microbes in the air might be used in the future to estimate densities of pear psylla or detect the amounts of pesticide or pheromone left in the orchard. It might even be possible to calculate the densities of female moths from pheromone in the air.
Dunley said the late George Ing, a pear grower in Hood River, Oregon, used to ask researchers why they couldn’t invent a DNA wand that growers could wave over their trees to tell them how many insects were there.
"It’s not that crazy any more," Dunley said.
Although he thinks mating disruption will continue to be the foundation of codling moth control, new dispensers will be developed to replace hand-applied ones. Sprayable pheromones and puffers are already available, but –Dunley expects to see smart puffers that will dispense pheromones based on data from the weather monitoring and smart traps. They will emit pheromone only when conditions are right for the moths to fly and mate, rather than at specific times of day. This will avoid wasting pheromone, which is the most expensive part of the mating disruption –technology, Dunley said.
New insecticides and more diverse control strategies will increase the opportunities for biological control. It’s possible that natural enemies will be genetically modified to be resistant to certain pesticides so that they can survive and provide biological control in the presence of what would otherwise be toxic strategies.
Thirty years from now, genetically modified trees will be acceptable to the public, Dunley predicted, and trees modified with the biological pesticide Bacillus thuringiensis might be available. New breeding programs might develop trees that are resistant to pests or diseases, or at least tolerant of them.
He believes that organic production will continue to increase, and that organic and conventional producers will use similar pest control strategies, though different nutrition programs. Conventional production will move more towards soft programs, while organic production will become more mainstream.
"I think the future is bright," Dunley concluded. "The information age and technology will lead the pear industry forward.