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Greater Harmony Between Agriculture and the Environment
Lygus Management
Issue
Integrated pest management (IPM) plans must be flexible enough to accommodate
different insect pest pressures from year to year. After years of lesser
recognition as a cotton pest, Lygus bugs have become the number one
pest of cotton since 1998. Among growers, typical control measures for
Lygus have involved tank mixing combinations of broad-spectrum insecticides
in the unfounded hope that this practice will give more control over
the pest.
What has been done?
The UA College of Agriculture and Life Sciences has developed an integrated
pest management program (IPM) for Lygus in cotton aimed at reducing
insecticide use through adequate field sampling, adherence to threshold
guidelines, and using the right compound for the job. Above all, it
emphasizes avoiding pest pressures wherever possible. These measures
are being incorporated into the larger cotton pest management program,
and focus on reducing spray applications from mixed broad-spectrum insecticides
to more selective, targeted single insecticide applications. One key
to the success of the program has been the accurate identification of
single spray compounds that perform consistently against Lygus and knowing
precisely when to use them. The education component of this program
has assisted growers in implementing this strategy during the last four
cotton seasons.
Impact
In response to this IPM program, more than 50 percent of the region’s
cotton growers have changed their chemical tactics against Lygus by
switching to single compounds used strategically and at appropriate
rates as part of an IPM system. This has resulted in a two-thirds reduction
in the number of acres receiving spray mixtures for Lygus, while increasing
effective rates by about 20 percent. Arizona extension cotton specialists
have been able to teach and demonstrate to growers that these single
compounds are as effective or even more effective than broad-spectrum
combination sprays, and that this practice helps reduce the risk of
resistance in Lygus and other insects while minimizing negative impacts
on beneficial insects. More growers are now aware of the specific timing
(thresholds) required for the control of Lygus and for providing maximum
economic return. In 1999, growers applied the fewest number of sprays
statewide against Lygus in cotton since 1993, thus reducing their costs
per acre while protecting the environment.
The success of this program has led for the first time to efforts to
control Lygus across multiple crops (Lygus are highly mobile and feed
on several crops in addition to cotton). Growers have begun meeting
with Cooperative Extension personnel to develop cooperative plans involving
cropping sequences and cultural controls to reduce damage from Lygus.
Funding
Arizona Cotton Growers Association
Hatch Act, IPM 3-D Smith-Lever,
Agrichemical companies
Contact
Peter Ellsworth, area IPM specialist, Maricopa Agricultural Center,
The University of Arizona
37860 W. Smith-Enke Road, Maricopa, AZ 85239-3010
Tel: (520) 568-2273, FAX: (520) 568-2556
Email: peterell@ag.arizona.edu
http://ag.arizona.edu/crops/cotton/cotton.html
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