Washington State University and the Washington tree fruit industry are proposing a major effort to help orchardists transition away from organophosphate pesticides. The three-year project, costing 1.9 million dollars, will involve education about new pest management tools, development of pest management strategies, and assessment of the risks and benefits.
Mating disruption, which was commercialized in the early 1990s, has proven to be the key to reducing pesticide use, according to Dr. Jay Brunner, director of WSU’s Tree Fruit Research and Extension Center in Wenatchee.
In 1993, soon after mating disruption became available commercially, Brunner and entomologist Dr. Larry Gut (then at the Wenatchee research center) conducted a research project showing that a nonorganophosphate program was possible even with the products available at the time.
More impetus for switching from the traditional broad-spectrum pesticides came with the Food Quality Protection Act of 1996, which mandated that the U.S. Environmental Protection Agency reassess all pesticide tolerances. It required that the agency apply additional safety factors to protect the health of infants and children, take into account aggregate exposure to pesticides, and assess the cumulative risk posed by pesticides with similar modes of action. The review focused first on organophosphates and carbamates.
Initially, there was deep concern that critical pesticide registrations would be cancelled, leaving growers with inadequate pest controls. Registrations of many organophosphate pesticides, such as phosphamidon and methyl parathion, have indeed been cancelled, while use of some others, such as Lorsban ((chlorpyrifos), Imidan (phosmet), and Guthion (azinphos-methyl), has been restricted.
But the act also provided fast-track registration for reduced-risk pesticides and organophosphate replacements, which led to many new products coming onto the market. Brunner said chemical manufactures had been aware, even before the FQPA, of the changing political environment and the need to develop new technologies and chemistries.
“The end story with FQPA was, yes, there was a loss of old products, but there was registration of a lot of new technologies for pest control,” Brunner said.
Between 1995 and 2005, the amount of organophosphate insecticide (active ingredient) dropped by almost 60 percent because of the loss of registration of some insecticides and growers’ adoption of alternative controls, particularly mating disruption.
Mating disruption is now used on 70 percent of Washington’s apple acreage. Despite the availability of new products, 60 percent of the insecticides used in Washington apple production nowadays are organophosphates, and most of that use is directed against two pests, codling moth and leafroller. Guthion is scheduled to be phased out within five years.
It’s not simply a case of substituting new pesticides for the old broad-spectrum insecticides, Brunner notes. Growers need help in making the transition to the newer and safer technologies. Because of the complexity of the new technologies, it will take a lot of education, organization, and coordination. Information must be available in a form that’s readily accessible and understandable. A Web-based Decision Aid System developed by WSU will help with that (see “Timing is critical,” page 14).
A deterrent to adopting new pest management systems might be the expense, which could be 20 to 50 percent higher in terms of product cost, Brunner said. However, potential benefits include a safer working environment, fewer concerns about environmental impact, and greater market access.
“I don’t think we can ever promise people we’re going to make more money if we transition to these new products and have a more responsible system, but I think we will be able to demonstrate that moving in this direction is the right way to go,” he said.
It deals with social issues, and environmental issues, and helps to maintain access to markets or even open up new ones, he added.
Despite the advances made in pest controls over the years, the codling moth problem is something that growers can’t solve, but can only manage, Brunner said. “You’re never going to eliminate it as a pest problem. The objective is to manage pest populations—have a management strategy that keeps populations low over a long period of time without disrupting other parts of the orchard ecology,” he said. “Any time you change something in a biological system, you’re going to have some kind of a counter reaction. It’s a dynamic system; it’s always changing.”