Applications on Cotton
August 30, 2000
Cotton producers spend $75 million annually to control the tarnished plant
bug. This year, Agricultural Research
Service scientists will test the effectiveness of combining
remotely-sensed, multispectral images with pest-scouting data to develop
variable insecticide prescriptions that may do a better job of controlling this
ARS entomologist Jeffrey Willers at the
Research Laboratory at Mississippi State, Miss., along with colleagues at
the Stennis Space Center,
Mississippi State University and
Louisiana State University, will be building
on research conducted in 1999. This research indicated that scouting and
multispectral imagery data can be combined to create a geo-referenced pest
density map. Such a map could then be uploaded into a pesticide ground sprayer
that would dispense pesticide only where needed.
Cotton producers have traditionally had to depend on labor-intensive and
time- consuming methods to determine levels of infestation--like searching for
pests in randomly selected small sections of large fields. This often results
in inaccurate pest counts and the spraying of entire fields, without regard to
variations in pest density.
The new system uses multispectral imagery to draw a correlation between
plant vigor and pest density. It relies on a digital camera sensitive to
different wavelengths of light mounted in an aircraft flying over a cotton
field at various altitudes. The camera records images that can then be
processed to display variations in plant vigor. Next, scouts use transect-line
search patterns and drop cloths to search for plant bugs in each of the areas
corresponding to the different stages of growth captured by a digital image.
ARS researchers have found that plant bugs are more common in areas with more
This system is not only better at locating a variety of pests, but also
provides growers with a more cost-effective method of controlling them by
improving the placement and timing of pesticide applications. Rather than spray
an entire field at one rate, this system allows growers to vary the coverage.
Unsprayed areas can act as safe havens for a variety of beneficial insects that
can then repopulate the field after spraying. This all translates into less
ARS is the chief research agency of the U.S.
Department of Agriculture.
Scientific contact: Jeffrey L. Willers, ARS Crop Science Research
Laboratory, Mississippi State, Miss.; phone (662) 320-7383, fax (662) 320-7528,