Apple, pear, and walnut growers will have several opportunities this winter to learn how to take advantage of natural enemies in their orchards for controlling key pests.
Washington State University entomologist Dr. Vince Jones expects to see a move towards more precise integrated pest management in apples and pears in the future. This will be based, he says, on better monitoring of both pests and natural enemies and reduced rates of insecticides, with mating disruption of codling moth as the foundation.
Jones is the lead scientist in a major research project that aims to enhance biological control of pests in western apple, pear, and walnut orchards that was funded through the federal Specialty Crop Research Initiative. During a session of the Washington State Horticultural Association’s annual meeting on December 6, Jones and his colleagues will discuss new tools and strategies that they are developing for getting the most out of natural enemies. Dr. Nick Mills, entomologist at the University of California, Berkeley, and a cooperator in the project, will be there to tell what he has learned from studying how commonly used pesticides affect parasites and predators.
Jones is developing traps that growers can use to accurately monitor natural enemies in their orchards. When trees are attacked by pests, they give off chemical cues— known as herbivore-induced plant volatiles—that enemies pick up as a signal to move in to attack the pests. These volatiles can be used in lures in Delta traps so growers can monitor natural enemies in their orchards so they can take measures to preserve them.
These traps are still at the experimental stage, but Dr. Jay Brunner, director of WSU’s Tree Fruit Research and Extension Center in Wenatchee, said it is hoped they will be produced commercially in the future.
Jones is also developing phenology models for common natural enemies so that growers can time insecticide sprays when they are least likely to affect biological control. The models will be accessible via WSU’s online Decision Aid System.
More in-depth information about enhancing biological control will be provided during a short course entitled “Focusing on Tomorrow Today,” which is scheduled for February 7 and 8 in the Pacific Northwest and February 22 and 23 in Stockton, California. The Northwest course will be telecast between three locations in Wenatchee and Pasco, Washington, and Hood River, Oregon.
Brunner said the interactive short course will include quizzes, case studies, and small-group exercises and discussions. At the end of each day, there’ll be a social time when participants can interact informally with the speakers and look at posters on the topics covered.
Jones said he believes insecticide sprays will always be needed at some level, but pesticide label rates are based on the worst-case scenario, which means that in most situations they are higher than they need to be, he said.
“I don’t think we need the rates we’re using,” said Jones, who this year began studying the implications of using a ten-fold reduction in rates of some of the newer pesticides, but applying them perhaps twice as often. In theory, that should mean a fivefold reduction in residues on the fruit as well as the potential for better biological control of pests of secondary pests.
“The idea is that residues are a key issue for consumers and for export, and if we can cut the rates down and not compromise control, you’re really in a better situation with better biocontrol,” he said. “I think it’s a really fruitful direction to go.”
He also thinks growers could consider spraying only alternate rows (as with the alternate row middle system), particularly when applying a treatment for something such as fireblight that needs to be applied within a short time frame.
To learn more about the short course or to register, check the Web site: http://enhancedbiocontrol.org.