New computer and Web tools for tree-fruit growers ease decision making

By Renee Stern

Contributing Editor

Tree-fruit growers are gaining new tools to help make faster and more accurate decisions about horticultural, economic and other operational questions.

One of the newest is VCHERRY, The Virtual Cherry Tree—a Michigan State University computer model that illustrates how tree-training and pruning decisions affect crop-load development.

Another is Washington State University’s online Integrated Pest Management Decision Aid System, which pulls together several pest and disease models in conjunction with weather station data to provide management recommendations.

VCHERRY should be available this summer in a free beta version for growers to test, says East Lansing-based MSU horticulture professor Greg Lang, who developed the model. Still to be determined is what fee, if any, will be charged for the finished product.

Tim Dahle, owner of Dahle Orchards and Sundance Organics in The Dalles, Ore., says Lang’s presentations at industry meetings made him a believer in the need for a tool like VCHERRY.

“There are a lot of new people getting into the business,” he says. “Even if they’re experienced horticulturists with pome fruit, cherries are different and they can make a lot of mistakes.”

A revolution in decision making

WSU’s online pest-and-disease system was designed with Washington growers in mind, as the models it contains haven’t all been validated for other regions, says entomology professor Vince Jones, one of the program’s designers based at the university’s Tree Fruit Research and Extension Center in Wenatchee. Michigan growers have a similar tool, and New York researchers have expressed interest.

The Washington system debuted in spring 2007 with 12 beta testers and quickly gained an enthusiastic following of 500 users by the end of that season. Jones estimates about a third of the state’s tree-fruit decision-makers now have signed on.

Byron Phillips, IPM consultant with Columbia Fruit Packers Inc. in Wenatchee, was one of the original testers. Not using the program, he says, “is like trying to farm without a sprayer or trying to farm without a tractor.”

“It’s revolutionary,” says Nick Stephens, owner of Columbia IPM Inc. in Wenatchee.

“It’s the most powerful information tool since the model itself.”

Other decision aids available for tree fruit growers include programs to estimate risk and return over time for investments in technology, machinery or new plantings, as well as to calculate the economic value of lost trees.

Playing virtual ‘what ifs’ in your orchard

VCHERRY allows growers to select growing region, soil type and rootstock/scion combinations, then demonstrates how different training systems and pruning decisions affect canopy development and fruit distribution over several growing seasons.

“You can try different things until you achieve the desired result down the road and not just for the coming season,” Lang says.

Unlike mistakes made with real trees, virtual mistakes are painless and quickly corrected, Dahle says.

In addition to determining how best to establish a young orchard, the model also can help train orchard managers and field workers, giving them speedy visual demonstrations of pruning decisions, Lang says.

The model tracks fruit and leaf ratios on each virtual tree, predicting crop loads, fruit size and quality, and how that fruit is distributed in the canopy—all factors affected by specific pruning decisions, he says.

Lang hopes to add a way to interpret canopy shading. Too much shade within the canopy can affect color or even kill off fruiting spurs, reducing the tree’s production capacity over time.

“As we get more familiar with the subtleties, we can pinpoint in more depth the effects of horticultural decisions,” he says. Horticultural models have lagged behind pest and disease models.

Lang is working with New Zealand’s stone-fruit industry to adapt the model for apricots.

That’s the start for what may be a framework for similar models for other tree fruit, he says.

IPM made simple

The WSU IPM system is currently available to users for no charge, but Jones says some fee later may be added to cover costs now funded by grants.

The program’s speed and ease of use make it accessible to anyone, Phillips and Stephens say.

Phillips says he learned the ropes through experimentation rather than using the accompanying tutorial.

“It’s so convenient,” Stephens says. “I go online and click a button and there the information is.” With laptops and other wireless devices, growers can access the system anywhere.

That’s particularly important when many new pest and disease controls demand pinpoint timing, Phillips says.

Dialogue boxes also provide information on potential effects on secondary pests and beneficial insects, guiding growers through the tradeoffs.

Growers can select the nearest public weather station to their site to tailor forecasts and recommendations or load data from their own stations. Links to National Oceanic and Atmospheric Administration zone forecasts also help users plan for potential threats and schedule necessary control measures, Phillips says.

“This puts IPM back in the hand of the end user by making it easier to implement,” Stephens says. Management complexity has been a barrier to IPM adoption for some growers.

Jones says developers focused on keeping the system lean, paring down options to time-sensitive needs for quicker and easier navigation.

“The more you add to it, the more you clutter it and slow it down,” he says, adding that other sites offer help with questions where timing is less critical.

But improvements are in the works. This year’s project provides a history function, allowing growers to look back at a season’s worth of recommendations, actions and results, he says.

Future features will include organic pest-management recommendations and a Spanish-language format.

Phillips says all growers should log onto the system and try it.

“It’s going to give them a much better understanding of what’s going on in their fields,” he says.

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For more information on these and other models:

■ VCHERRY, The Virtual Cherry Tree:

■ WSU IPM-Decision Aid System:

■ Enviro-Weather, a pest and production management tool for Michigan growers:

■ Grower’s Technology Economic Assessment Model:

■ Crop Profitability Analysis:

■ Tree Loss Calculator:

■ Individual Tree Loss Calculator: