To ensure that delicious U.S.-grown grapes are
available year after year, ARS scientists are learning more about how to
protect grapevines from Pierce's disease. Click the image for more
information about it.
Sleuth Glassy-Winged Sharpshooters' Hangouts
By Marcia Wood
February 18, 2004
No one can say for certain where
the glassy-winged sharpshooter, a half-inch-long pest of grapes and other
crops, prefers to live. To find out, Agricultural Research Service scientists
are investigating where sharpshooters are most likely--at any given time of the
year--to rest, feed, lay their eggs or, perhaps most important, to ingest and
transmit Xylella fastidiosa, a bacterium harmful to plants.
This microbe causes Pierce's disease of grapes. What's more, in other
plants, X. fastidiosa causes other diseases, such as almond leaf scorch
and citrus variegated chlorosis. Glassy-winged sharpshooters that feed on
infected plants can spread the bacteria.
In the past decade, Pierce's disease has caused approximately $14 billion in
crop losses and pest control costs in southern California vineyards. But losses
could reach even higher levels if this insect, first detected in California in
1989, continues to expand its range.
To learn more about glassy-winged sharpshooters and other insects that
transmit X. fastidiosa, ARS entomologist Russell L. Groves is
meticulously monitoring an extensive network of insect traps that he has
established in glassy-winged sharpshooter infested areas of California's
central San Joaquin Valley. He's based at the ARS
San Joaquin Valley Agricultural Sciences
Center in Parlier.
The traps, hung from poles, are made of panels of bright-yellow cardboard
coated with a sticky substance. Glassy-winged sharpshooters, attracted to the
bright color, end up stuck to the panels.
Once a week, year-round, Groves checks these traps to determine changes in
the abundance of the insect from season to season and to delineate variations
in the glassy-winged sharpshooters' use of plants in and around vineyards,
orchards and fields.
Results from this research should help growers get more from their
pest-control dollars. For example, the investigation may yield new, more
precise information about where insects acquire X. fastidiosa in the
central San Joaquin Valley, at what point they move into vineyards, and when
they spread the bacterium into grapes.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.