Dr. Wee Yee, entomologist with the U.S. Department of Agriculture in Yakima, Washington, is conducting research to assess the likelihood of cherry fruit fly becoming established in certain overseas markets that are concerned about potential infestations of the pest, such as Indonesia and Thailand. Dr. Lisa Neven is cooperating on the project.
Results might also be applicable to the situation in California, as his research, using an existing model, should also show whether cherry fruit fly could potentially survive in the warm climate of the state’s commercial cherry growing areas or not.
Dr. Mike Willett, vice president for scientific affairs at the Northwest Horticultural Council, said if the research shows that the fly is unlikely to become established in California’s cherry growing regions, it would give the Northwest a logical reason to ask California to reconsider the extent of the restrictions that they place on the movement of cherries from the Northwest into that state.
Yee’s research is part of an effort to develop a systems approach to meeting quarantine concerns about cherry fruit fly that would also be based on management and detection practices.
He has been evaluating the efficacy of the tests used for detecting cherry fruit fly maggots in cherries. A couple of methods can be used. One involves crushing the cherry and putting it in a brown sugar solution, and the other involves putting the crushed cherry in hot water. Sometimes the solution is in a clear glass bowl, and sometimes in a black pan.
Last year, Yee conducted tests, using cherries from an experimental orchard that was managed like a commercial orchard. He collected fruit, crushed the cherries, and then had three people (including himself) inspect them for larvae. They then examined the samples under a microscope to see how many larvae they had missed during their visual inspection. Though their initial detection rate was high, Yee will develop ideas of how to improve the efficacy.
Yee will also study the ecological adaptability of the cherry fruit fly and its typical distribution in an orchard. Most of the cherry orchards in Washington are well managed for cherry fruit fly, so probably don’t have internal infestations, he said. “You would expect the infestations to be around the edges if the flies are landing on the first trees they encounter,” he said.
Other components of the systems approach are already in place, such as control with the GF-120 bait during the growing season and postharvest sprays of dimethoate to disrupt the life cycle of larvae in fruit left in the orchard after harvest, he said. The research is funded by the U.S. Department of Agriculture’s Technical Assistance for Specialty Crops program.