Day Will Suffocate Fruit Pests
By Jim De
December 6, 1996
Scientists with the
Agricultural Research Service are
devising a method for suffocating Mexican fruit flies trying to hitch a ride in
grapefruit shipments. Studies are being conducted under a cooperative research
and development agreement with TransFRESH Corp., Salinas, Calif.
Fly invasions can trigger costly eradication programs requiring aerial
sprays of insecticide. Plus, the pests can devastate farm production and trade,
because quarantines must usually be imposed to prevent their spread. Methyl
bromide is the most common quarantine treatment available for grapefruit and
other citrus. But this pesticide is slated to be phased out by 2001 for
A promising alternative is a method called CA--controlled atmosphere. A
dramatically altered but precisely determined balance of airs three main
gases--oxygen, nitrogen and carbon dioxide--is pumped into a shipping container
carrying fruit. The fruit flies suffocate because the atmosphere holds less
than 1 percent oxygen instead of normal airs 20.9 percent.
ARS scientists have seen promising results from lab tests with, to date,
more than 100,000 fruit flies and 5,000 grapefruit. In some tests, all the
flies died in 1 to 3 days without compromising fruit quality.
An effective CA method would give shippers a new, in-transit insurance
policy. Even if Mexican fruit flies are found infesting a growing area, CA
would stop them from surviving the trip to a new locale in outgoing fruit
shipments--and the shipments could continue. The scientists also are exploring
CA as a quarantine treatment for oranges and to preserve the quality of mangoes
A feature article about this research appears in the November 1996 issue of
ARS Agricultural Research magazine. A
version of the article is on the World Wide Web.
Scientific contacts: Robert Mangan and Krista Shellie, Crop Quality
and Fruit Insects Research, Subtropical Agricultural Research Laboratory,
Weslaco, Texas, phone (210) 565-2647.