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[nafex] FW: Putting the "Bite" on Plum Curculio Weevils

From: "ARS News Service" <isjd@ars-grin.gov>
To: "ARS News List" <ars-news@ars-grin.gov>
Subject: Putting the "Bite" on Plum Curculio Weevils
Date: Wed, Jun 6, 2001, 9:19 AM

Putting the "Bite" on Plum Curculio Weevils

ARS News Service
Agricultural Research Service, USDA
June 6, 2001
Linda McGraw, (309) 681-6530, mcgraw@ars.usda.gov

Anyone who has ever bitten into a "wormy" apple will appreciate the efforts
of Agricultural Research Service chemist Fred J. Eller, who has developed
and patented a pheromone bait that can give fruit growers an early warning
of plum curculio weevils. Pheromones are chemicals secreted by animals,
especially insects, that influence the behavior or development of others of
the same species, often acting as a sex attractant.

Plum curculio weevils, Conotrachelus nenuphar, attack apples, peaches,
cherries, pears, apricots and plums in the southern and eastern United
States. Adult female weevils lay eggs under the skin of developing fruits,
causing yield loss and scarring. Normally, growers become aware of the
pests only after the eggs are laid, when a telltale "crescent moon" blemish
appears on the fruit. Once this moon appears, the fruit is permanently
scarred. The plum curculio is only one-quarter inch long, with a brown and
gray body, and a long snout. The female beetle lays her eggs inside pome
and stone fruit, causing "wormy" fruit.

Eller, based at ARS' National Center for Agricultural Utilization Research
at Peoria, Ill., identified the pheromone released by the male curculio
weevil. The chemical attracts both female and male curculios. He
incorporated the chemical, called grandisoic acid, into a trap that was
originally designed for boll weevils by ARS researchers in Mississippi.
Eller placed several traps baited with the chemical attractant in orchards
at blossom time. He found significantly more weevils in the baited traps
than in the unbaited traps.

More work is needed to expand the use of the pheromone and to add volatile
compounds, such as fruit odors, to enhance the attractiveness of the
pheromone and capture weevils even at low densities. Currently, other
researchers at the ARS Appalachian Fruit Research Station, Kearneysville,
W.Va., are combining the pheromone that Eller identified with apple odors
to make a more attractive lure for the plum curculio.

Ultimately, a pheromone-baited trap may one day offer a reliable monitoring
tool to help growers reduce pesticide use by spraying only after pest
populations are detected and prior to significant crop damage. ARS is
seeking companies to license the technology.

ARS is the chief scientific research agency of the U.S. Department of


Scientific contact: Fred J. Eller, ARS New Crops and Processing Research
Unit, Peoria, Ill., (309) 681-6232, fax (309) 681-6686,

This item is one of the news releases and story leads that ARS Information
distributes on weekdays to fax and e-mail subscribers. You can also get the
latest ARS news on the World Wide Web at
* Feedback and questions to ARS News Service via e-mail: isnv@ars-grin.gov.
* ARS Information Staff, 5601 Sunnyside Ave., Room 1-2251, Beltsville MD
20705-5128, (301) 504-1617, fax (301) 504-1648.


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