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Pest-Removing Treatments Examined for Cherry
Packing Operations By
Jan Suszkiw March
Using food-grade surfactants, Agricultural Research Service (ARS) scientists in Wapato, Wash., are
testing a new method of ridding packed sweet cherries of mites, thrips and
other surface-feeding pests.
According to ARS entomologist
Hansen, such pests pose more of a consumer-marketing problem than a
field-production one, since they can occur on sweet cherries that have been
packed for domestic sale or export. In addition to culling and sorting
measures, Hansen is experimenting with dips, baths and sprays containing
polydimethyl silicone emulsions and other food-grade surfactants, which, in
effect, wash the pests off the cherries' surface.
Surfactants are typically used as wetting or dispersing agents in
products ranging from soaps and shampoos to paints and insecticides. But recent
studies by Hansen and others have shown that some silicone-based surfactants
will remove spider mites, thrips and mealy bugs from apples and pears.
Hansen's surfactant studies at ARS'
and Vegetable Insect Research Unit in Wapato kicked into high gear in 2005
when ARS entered into a research agreement with the California Cherry Advisory
Board (CCAB). The collaboration makes
sense since Washington and California are the nation's top two sweet cherry
producers, exporting more than half their fresh-market harvests.
Besides fruit quality, the success of international sales hinges on
U.S. cherry exporters' ensuring pest- and disease-free shipments to avoid
rejection or delay of the shipments at the trader's port.
Under the ARS-CCAB agreement, Hansen is conducting research to
identify emulsifiers and other surfactants that will remove a variety of pests.
He's also looking for ways to identify exposure times that won't delay online
packing operations, as well as ways to compare the effectiveness of spraying
cherries versus immersing them in surfactants. In a supporting study, Hansen's
collaborators at the University of
California-Davis examined surfactant-treated cherries for fruit damage, but
they found nothing significant.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.