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Zapping Hawaii's Pesky Fruit Flies, Grid by
Grid By Marcia
October 10, 2002
A quartet of exotic tropical fruit flies--Oriental, melon,
Mediterranean and Malaysian-- can easily turn what should be a fresh, luscious
tropical fruit or vegetable into a disgusting mess. That's because the fruit
flies' tiny, wriggling maggots spoil what would otherwise be a delectable crop.
Service scientists and their University of
Hawaii collaborators are targeting these troublesome flies in an Areawide
Integrated Pest Management Program on Fruit Flies in Hawaii. The goal is to
give Hawaii's growers the latest and best science-based, environmentally sound
strategies to reduce crop losses and, at the same time, lessen the need for
The program will help farmers keep the fruit flies under control
in carefully delineated suppression grids. These grids include not only
participating growers' fields and orchards, but also nearby vegetation where
significant numbers of the fruit flies live and breed, according to ARS
entomologist Eric B. Jang. Jang and ARS entomologist Roger I. Vargas lead the
program. They are based at the agency's
U.S. Pacific Basin Agricultural
Research Center in Hilo.
The program's approaches for going after fruit flies in the
suppression grids are practical, affordable and workable. Using grids is very
different from attempting to obliterate the fruit flies everywhere they live in
the Hawaiian Islands chain.
Today, ARS scientists and co-investigators are employing such
control methods as sanitation, to remove as much infested fruit as possible,
and male annihilation, accomplished with traps that contain a lure that's
irresistible to male fruit flies plus a second compound that kills them once
they touch or eat it.
Other control techniques include applying protein-based bait
sprays, which are added to a compound that kills the flies, and rearing and
releasing a beneficial wasp, Fopius arisanus, that attacks fruit flies.
In addition, scientists are turning loose laboratory-reared, sexually sterile,
male melon flies to mate with wild, fertile females. That causes melon fly
populations to crash, according to ARS geneticist Donald O. McInnis. For this
purpose, McInnis developed a unique, exclusively male line of melon flies at
the center's Honolulu laboratory.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.