Find the WSU-Decision Aid System at

Find the WSU-Decision Aid System at

Years ago, when fruit growers relied heavily on organophosphates for pest control and sprayed by the calendar, pest management decisions were relatively simple.

A grower who needed advice could check in the Spray Guide or phone the local Extension agent.

“Everyone had a paper copy of the Spray Guide, and it was sophisticated enough for the time,” recalls Dr. Jim McFerson, manager of the Washington Tree Fruit Research Commission. “But think about how that would work now, and it makes no sense.”

Today, growers can go to their computers, tablets, or smartphones any time of day or night for help in deciding how to control pests.

Washington State University’s Decision Aid System (DAS) website provides not just the Spray Guide but a wealth of information including degree-day models for diseases, pests, and natural enemies; historic and current weather data from the university’s 150 AgWeatherNet stations; 10-day weather forecasts from the National Oceanic and Atmospheric Administration (NOAA); and information on Maximum Residue Levels in export markets to guide pesticide choices. The site also explains what the degree-day model data mean from a management standpoint.

“DAS is really about providing the information that pest managers need to make the best decisions,” said Dr. Vince Jones, Washington State University entomologist and DAS director. “We’re not making the decision. They’re making the decision. We’re providing weather data and models and all the insights that the people who developed the models have about what this means in terms of your management and how to deal with it, and we’re doing it ahead of time so you can respond.

“It’s not a repository of research information,” he emphasized. “It’s trying to take that research information and put it into a package that’s available to people when they need it, or slightly before they need it.”


Jones noted that funding for WSU Extension dropped by 52 percent between about 2008 and 2012. The few remaining Extension specialists in Washington no longer have time to field routine calls from growers.

“So how do you deal with an industry that has five billion dollars of impact on the state’s economy? You’re got this huge industry with a lot of demand, and the education system’s hamstrung by the fact that it does not have many people. This is a way to get information out in a way that can have an impact almost immediately.”

McFerson said DAS is more than just a practical tool for growers. “To me, this is the most exciting Extension technology that WSU has developed and is offering and improving. It really changes the way Extension operates. DAS is part of what may someday become a statewide Decision Support System at WSU. It’s charting a new course for delivery of science-based knowledge, interaction, and engagement with the industry.”

An important feature of DAS is that it’s interactive. For example, growers can enter data in the model to find out what the impacts on pest or natural enemy populations would be if they applied different pesticides.

The site has about 350 regular users, representing about 80 percent of Washington’s 230,000 acres of tree fruits. Some users are probably companies that access data from multiple weather stations, but growers with small acreages also use the system.

“The bigger your operation, the more you need something like this because you’re trying to cover so many acres,” Jones said. “On the other hand, if they’re a small grower doing it on their own—and they don’t have somebody they hire to do it—they actually need this as well because it helps them to get information and saves them time.”

Visitors to the site need to log in, which ensures that they’re not overwhelmed by unnecessary information.

“We can give you all of it, but you would drown in data,” Jones said. Instead, users will only see information relevant to their location and the crops they grow as well as the time of year.


Since Jones launched DAS in 2005, access to the site has been free, but that will change next spring when WSU will charge an annual fee of $150 for each weather station accessed.
DAS has a full-time programmer and a part-time manager/educator who does outreach and some programming for DAS as well as other research.

WSU Cooperative Extension has committed to pay for the first programmer, but DAS needs roughly $150,000 a year to cover the second programmer and manager/educator’s salaries, site maintenance, overheads, and other costs not met by WSU.

Until now, DAS been funded mainly by grants from the Research Commission and elsewhere. Jones said it needs stable, long-term funding because granting agencies don’t want to pay to maintain a system. They want to pay for new features and new technologies.

The result has been that DAS has many new features in the works that it’s not yet been able to implement on the website.

“We can think them up faster than we can get them up and operating,” Jones said. “User fees will allow us to add the new features that we’re working on now and have been working on for the last two years.”

New features

A recent addition called OPENED (Orchard Pesticide Effects on Natural Enemies Database) allows users to select pesticides based not just on their efficacy against pests, but on how they affect beneficial insects, too.

“So if you have a mite problem, for example, you don’t want to apply anything that’s going to affect predators of spider mites,” Jones said. “Or if leafrollers is your key problem, you want to choose pesticides that don’t affect natural enemies of leafrollers.”

New degree-day models are being added for two mite species (European red mite and two-spotted spider mite) and two beneficial lacewing species, Chrysoperla carnea and Chrysopa nigricornis. Several more models are in the pipeline.

Mike Hodge, field representative with G.S. Long in Yakima, said he finds the existing models for codling moth and fire blight particularly useful and is looking forward to seeing a pollen-tube growth model on DAS to help time chemical thinning sprays.

One feature under development is a cell phone/tablet app to allow users to enter trap count data in the field then have it summarized and displayed on DAS or on the cell phone.
Long-term forecasts

The Research Commission and WSU Extension are funding a project that will enable DAS to provide longer-term forecasts. The weather data is manipulated into degree-days and will provide a fairly accurate one-month forecast of heat unit accumulation, which is what drives insect development. In trials, the average error has been about three days.

“These long-range forecasts aren’t super accurate but it’s a good warning of how things are starting to fit together from a pest management perspective,” Jones said.

A grower or horticulturist will be able to get a sense of how sprays for the various pests interact. For example, if a grower applies a spray for codling moth that is combined with oil for greater efficacy, it will also impact spider mites. Growers might not be aware that they’re controlling multiple pests with one spray.

By following DAS recommendations, growers can get maximum benefit from their pesticide sprays and reduce the number they need to apply.

“Timing is everything with management,” Jones said. “We’re giving you information which is time sensitive, and we’re giving it to you before it actually happens, so you’re not waking up and finding out there’s a problem you didn’t know about that needs to be dealt with today. You should have known a week ago, because our forecast’s currently ten days into the future to show what the issues are that you’ll be facing in the near future.

“That’s the whole purpose of DAS—to make sure people aren’t caught unaware,” he emphasized. “The long-term goal of DAS is to have a management plan, not a reaction plan.”

In surveys, users have said that by DAS recommendations they saved an average of $75 per acre per year in spray costs, which adds up to about $16 million industry-wide. Jones said DAS today is similar to what he envisioned many years ago, but its impact has exceeded his expectations.

“Scientifically, there are things I’ve done that are a lot more interesting, but to get that information out there and get it used is probably the most rewarding thing,” he said. •