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researchers find the wasps?
(May 2000 magazine
Parasitic Wasps Could Curb
Mealybug By Jennifer Arnold
August 17, 2001
In an ongoing search for a biological control for papaya
mealybug (Paracoccus marginatus), researchers have singled out two
parasitoid wasps for the job. The researchers are entomologist
Schauff at the Agricultural Research
Service and John Noyes, a colleague at The
Natural History Museum, London, England,
The papaya mealybug is believed to be native to Mexico and
Central America and has the potential to attack a variety of agricultural
crops, including papaya, citrus, cotton and avocado, in addition to preying on
ornamentals, such as the hibiscus. The papaya mealybug was recently introduced
into the United States, with the greatest concentrations of the insect being in
Florida, Puerto Rico and the U.S. Virgin Islands.
Mealybug damage could cause economic losses in the tens of
millions of dollars if left to spread in the United States.
The two candidate wasps, newly discovered species in the
genera Pseudleptomastix and Acerophagus, were collected during
field research in Texcoco, Mexico, in 2000.
These tiny wasps are almost invisible--with one species just
about one millimeter long--and look like the average stinging wasp. Dubbed the
mealybug destroyers, the tiny females sting the mealybugs and lay
an egg inside each one. When the eggs hatch, the larvae eat the internal
organs, killing their hosts.
ARS scientists, in conjunction with USDA
Animal and Plant Health Inspection
Service scientists who have reared and released the wasps in the Caribbean,
are now seeing a tremendous impact. They are confident a parasite-release
operation can be an effective tool in the war against papaya mealybugs.
Already, APHIS found that the release of the parasitic wasps
brought a 98 percent reduction in mealybugs near the research sites. In some
areas, scientists are even having trouble finding enough to work on. And the
wasps pose no threat to people, plants or any insects other than the papaya
ARS is the U.S. Department of
Agricultures chief scientific research agency. Entomologist Schauff
is based in Beltsville, Md., with ARS' Systematic Entomology Laboratory.