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New Computer
Program Helps Growers Protect Poinsettias
By Marcia Wood
December 21, 2001Colorful poinsettias are favorites
because they rank as the nation’s top-selling potted flowering plant. But
poinsettias, Euphorbia pulcherrima, are also a favorite of the
silverleaf whitefly.
This greenhouse pest, known to scientists as Bemesia argentifolii, is
no bigger than a ballpoint pen tip. It sucks juices from the poinsettia leaves
and stems and weakens the plant, according to
Agricultural Research Serviceentomologist Gloria DeGrandi-Hoffman, based at the agency’s
Carl Hayden Bee Research Center in
Tucson, Ariz.
To clobber the tiny whiteflies, DeGrandi-Hoffman and colleagues have
developed user-friendly software called BIOCONTROL-POINSETTIA. It will help
growers determine how best to use a wasp, Eretmocerus eremicus, a
natural enemy of whiteflies. Female wasps lay their eggs in whitefly young. The
wasp eggs then develop inside the whiteflies, eventually killing them.
The new computer model helps growers determine how many wasps to turn loose
in their greenhouses to attack the whiteflies. It will also indicate when and
how often they might use the wasps for whitefly control. The software augments
the growers’ expertise and experience, giving them a resource for an
objective analysis.
De-Grandi-Hoffman developed the software at the urging of colleagues John P.
Sanderson at Cornell University, Ithaca,
N.Y., and Roy G. Van Driesche at the University
of Massachusetts, Amherst. Mark Hoddle, University of California, Riverside, along
with Sanderson and Van Driesche, first discovered E. eremicus’
impressive capabilities as a biocontrol agent for whitefly.
To build the program, DeGrandi-Hoffman entered whitefly and wasp
information, gleaned from years of work by Sanderson and others, into a
mathematical form for the computer to analyze. The result sits on a single
floppy disk and runs on any personal computer equipped with Windows 98 or
later.
An article in ARS’s monthly magazine, Agricultural Researchtells more.
ARS is the U.S. Department of
Agriculture’s chief scientific research agency.
