WENATCHEE, Wash. — Providing consumers with the best possible eating experience is a constant goal of the Washington tree fruit industry and its research partners. That goal is being met through delicious new varieties of fruit as well as through more behind-the-scenes developments. One of those recent developments has growers using fewer inputs to retain apple fruit quality after harvest.
 
Traditionally, harvested apples and pears are given a drench with a fungicide that controls postharvest rots. But consumers prefer fruit that is not treated with pesticides after harvest, and regulators around the world are echoing that demand.
 
In order to respect consumer demands and stay competitive in the global market, an alternative means of controlling postharvest diseases is needed. Enter plant pathologist Chang-Lin Xiao, a researcher based at the WSU Tree Fruit Research and Extension Center in Wenatchee.
 
Multiple diseases
“The control of postharvest rots is very challenging because we have to deal with multiple diseases,” Xiao said. “Some marketing companies already have zero tolerance for decay, and most of the apple-producing countries in the European Union already severely restrict the postharvest use of fungicides.”
 
Xiao and his colleagues have tested a preharvest treatment that controls postharvest issues.
 
“Based on work done here, we were able to facilitate the registration of a reduced-risk fungicide in 2005 that helps manage postharvest diseases in apples and pears,” Xiao said.
 
In use in Washington, Oregon
The preharvest treatment is now in wide use in Washington and Oregon, with about 20 percent or more of apple and pear crops being treated with the new product.
 
“Our role was to work with the fungicide manufacturer to test the product’s efficacy,” Xiao said, “as well as to determine usage protocols in terms of how much to use, how often – and also in terms of the timing of applications.”
 
Problems with postharvest drench
One of the problems with the traditional postharvest fungicide drench, said Xiao, is that it necessitates wastewater treatment and risk contamination.
 
“The water used in the drenching process is recirculated,” Xiao said, “so there is a chance that nontarget fungal spores will survive the process and contaminate the fruit.”
 
Communicating with growers, packers
Xiao and his colleagues also have developed a new way of getting information about new pest and disease management strategies to those who most need them — the growers and packing house managers.
 
“We organized the WSU Fruit School,” Xiao said. He collaborated with retired WSU postharvest specialist Gene Kupferman to get the school up and running.
 
“With some financial support from the agri-chemical companies, we host the fruit school in May or August, so that fresh information gets to growers and packers in a timely manner,” Xiao said. “We get about 140 attendees at each annual meeting, which represents about 90 percent of the packing industry.”
 
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