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Greater Harmony Between Agriculture and the Environment
Reducing Insecticide Use in Arizona
Issue
Insecticide applications in cotton typically account for about half
of all insecticide use in the United States. New materials on the market
are now enabling cotton growers to reduce their spray applications while
maintaining competitive yields. These technologies also help growers
implement more ecologically-based IPM programs and become less dependent
on broadly toxic insecticides.
What has been done?
An integrated pest management program implemented two new tools in 1996
and continued their use through 2000: insect growth regulators (IGRs,
effective against whiteflies) and transgenic cotton (containing Bt effective
against pink bollworms). The University of Arizona College of Agriculture
and Life Sciences collaborated with growers, the USDA, the Arizona Department
of Agriculture, the Arizona Cotton Growers’ Association, Cotton
Incorporated, industry and others. Both of these tools are highly effective
against pests, but safe to humans and the environment. Based on insect
hormones, growth regulators disrupt the growth and development of insects.
Transgenic cotton is genetically engineered to carry its own biological
insecticide, targeting lepidopterous pests, within the plant tissues.
Impact
Nearly 100 percent of the cotton acreage in Arizona was sprayed multiple
times for pink bollworm and silverleaf whitefly in 1995; however, in
1999 and 2000 the majority of acres were never sprayed even once for
these two pests. This success was mainly due to the efforts of the Arizona
IPM program and the availability of IGRs and transgenic cotton in reducing
the number of insects that appeared. Weather patterns and other factors
may also have influenced the appearance of fewer numbers of insects
in 1999; however these trends have been sustained through 2000. Annual
cotton acreage in Arizona is usually over 250,000 acres.
As a result of this program, during 1999 the average foliar insecticide
use in Arizona cotton was the lowest in 21 years, according to state
records first kept in 1979. Overall, 1999 had the lowest number of foliar
sprays against all insect/arthropod pests in cotton during the 90s,
and the lowest costs per acre during the same period. In 1990, growers
applied about 11 sprays during the season at an average cost of $113.76.
By 1999 this number had dropped to 1.91 (between one and two sprays)
at an average cost of $37.18.
For silverleaf whitefly (SWF) in particular, the number of sprays dropped
from 6.6 per season in 1995 to 0.40 for the season in 1999. Lint quality
went from “very sticky” in 1992 to “very clean”
in 1999. In 1995 SWF sprays cost an all time high of $145.20 per acre,
and amounted to nearly 70 percent of the total foliar insect control
budget. By 1999 growers spent an average of $10.91 per acre on SWF,
which was only about 30 percent of the total foliar insect control budget.
This was the lowest amount of money per acre spent to control SWF since
its introduction to the state in the early 1990s.
Along with resistance management, these IPM efforts reduced insecticide
use, conserved biological control agents, and enhanced sustainability
and profitability.
Funding
Hatch Act
Smith-Lever 3(b) and (c)
Special Research Grants
Smith-Lever 3(d)
Other CSREES: Western Region IPM; National Pesticide Impact
Assessment Program, Western Region, PEST MANAGEMENT ALTERNATIVES; Cotton
Incorporated; Arizona Cotton Growers Association; Agrichemical industry
Contact
Peter Ellsworth, 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
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