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An ARS-discovered virus that causes sterility in corn earworms could
give farmers an environmentally safe weapon against this scourge of corn,
cotton and other crops. Also, the virus may have potential to knock
down related pests such as the legume podborer, tobacco budworm and fall
armyworm. Together, these pests cause an estimated $5 billion in damage
to various crops throughout the world. Attacking the corn earworm in its
moth stage, the virus, called gonad specific virus (GSV), infects only the
moth's reproductive system, deforming either ovaries or testes. Most
infected moths lack reproductive organs altogether. Based on lab studies,
scientists estimate that low levels of the virus cause sterility in 70 to
80 percent of infected moths. The rest become carriers, passing the virus
along to the next generation through mating. Scientists discovered the
virus in late 1993 in corn earworms at an ARS laboratory in Stoneville,
MS. Field tests of the virus are planned for later this year. ARS has
filed a patent application on the virus. (PATENT APPLICATIONS 08/348,175,
08/440,158)
Insect Neurobiology and Hormone Lab, Beltsville, MD
Ashok Raina, (301) 504-9396
Wood-boring wasps and beetles in the Mid-Atlantic states have a natural
enemy, and now ARS scientists have made it easier to identify this "good"
enemy--a family of wasps known as Aulacidae. An ARS study
collected nearly 800 specimens of the family from 10 sites in Maryland,
Virginia and West Virginia. Within this region, 15 of the 30 North
American species were found. ARS scientists determined that seasonal
flight activity for most species is in late spring and summer, but the
peak flight period varies slightly among species. Now a publication gives
a key for identifying them and information on each species' hosts and
areas where they live. The identification keys and data will be a
time-saving reference for biological control specialists and forest
entomologists.
Systematic
Entomology Laboratory, Washington, DC
David R. Smith, (202) 382-1783
A strain of the fungus Aspergillus flavus that is free of toxin
can crowd out strains producing aflatoxin in cotton bolls. In one ARS
test, that action eliminated 99 percent of the aflatoxin from a cotton
crop. Aflatoxin-contaminated cottonseed cannot be fed to cattle because
the toxin shows up in milk. ARS scientists tested the nontoxic strain
(AF36) by applying it to soils planted with cotton in Arizona. In both
1989 and 1990, AF36 displaced infecting strains during cotton boll
development. In 1989, 75 to 82 percent and, in 1990, 99 percent less
aflatoxin was measured in the cotton crop at maturity. Currently, an
experimental-use permit is being sought from the U.S. Environmental
Protection Agency for tests on commercial cotton fields. (PATENT
5,294,442)
Southern Regional Research
Center,
New Orleans, LA
Peter Cotty, (504) 286-4391
Insect-resistant sugarcane could deliver a knock-out punch to the West
Indian cane weevil, the newest adversary of Florida sugarcane. The
weevil, Metamasius hemipterus, eludes insecticides because it
tunnels inside cane stalks. But ARS scientists have identified eight
commercial sugarcane varieties the pest finds unappealing. In field
tests, weevils infested more than 20 percent of the stalks of two
susceptible varieties--Canal Point (CP) 85-1382 and CP 80-1743. But the
newly-identified sugarcane remained weevil-free. ARS scientists began
searching for weevil-resistant varieties shortly after the insect was
detected on cane near Lake Okeechobee, FL, in February 1994. Since then,
it has attacked the variety CP 85-1382 so severely that growers no longer
plant it. The weevil was detected in 1984, and it may have snuck into
Miami ports aboard produce shipments. It has not been found in other
states.
Sugarcane Field Station, Canal Point, FL
Omelio Sosa, Jr., (407) 924-5227
Last updated: October 30, 1996
Return to: Quarterly Report
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