Spray Reductions in Cotton


Nobody likes extra paperwork, but that’s exactly what the 15 cotton growers and pest-control advisors gathered at the Maricopa Agricultural Center outside Phoenix were doing on a recent winter Wednesday. Voluntarily.

Pesticide spray reduction chartEach was working on a detailed survey about their latest cotton harvest: identifying the pests and pressures that reduced yields, quantifying the number of insecticide and herbicide sprays they had made on their crops, and documenting why they had made each spray. The survey took about 90 minutes to complete, and a few of the pest-control advisors had driven 150 miles from across the border in California to take it.

Cash Veo, a pest-control advisor for seven growers and 7,000 acres of cotton in Arizona’s Maricopa County, said the survey is good ammunition.

“I think it’s good to get together as an industry and defend ourselves, more than anything,” he said. “Defend ourselves from the idea that we go out and spray chemicals for no good reason. This gives us an opportunity to put a reason to it. To quantify it.”

The survey, conducted by the University of Arizona's Dr. Peter Ellsworth and Dr. Al Fournier, does more than that. Their data, dating back to 1990, is a strong argument that integrated pest management succeeds in reducing harm to people and the environment while managing pests in a cost-effective way.

In short, the survey data shows that IPM works, in a big way.


Reduced Risk, Reduced Costs

“Growers were averaging 10 or 12 or 14 sprays in the early ’90s and they’re making two or three sprays now,” Ellsworth said. “When someone sees that data, it tells a story.”

Here’s another way to visualize it. In 1995, growers applied 4.15 pounds of active insecticide ingredient per acre of cotton. Over the last six years, the amount of active ingredient applied per acre was reduced by 3.26 pounds, or 77 percent, to less than 16 ounces per acre. 

“That’s the equivalent of applying less than a can of soda on an area the size of a football field just once over the cotton season,” Fournier said.

The story is summarized beautifully in one particular graph that shows the number of sprays growers made by year (and for which pest), as well as their pest-control costs per acre. Those costs peaked in 1995 at $300 an acre, and have dropped to about $50 an acre in recent years.

Technology has played an important part in those advances. Insect- and herbicide-resistant cotton varieties were developed in that time span, and the pink bollworm, once the major pest problem in Arizona cotton, was functionally eradicated.

“The old-timers still talk about the pink bollworm,” Veo said. “I don’t even know what it looks like.”

Ellsworth said that some people attribute all the reductions to the pest-resistant cotton strains, but it’s the combination of the resistant strains with well-planned IPM practices that really make the difference.

“In Mexicali, across the border, they have a cotton industry that in theory had access to all the same technology as growers here,” Ellsworth said. “What they didn’t have was a Cooperative Extension system to show them how to do IPM and do it right, so their recent practices were what we were doing in the mid-’90s.”

As part of an EPA project, Ellsworth and others brought IPM education to the Mexicali cotton growers.

“In the space of 17 months, they went from mid-1990s methodology to 2012 methodology and cut organophosphate usage and cut pyrethoid usage. It changed like that,” Ellsworth said, snapping his fingers.


Expanding the Program

The Crop Pest-Loss and Impact Assessment program began as a Western IPM Center work group and became a signature program in 2012. Ellsworth, Fournier and Dr. John Palumbo hold a series of annual workshops around Arizona to gather the data from Arizona and the low desert regions of California for the region’s major cropping systems, including head lettuce, melons and cotton. 

The goal now is to expand the program to a different cropping system in a different area.

“When I present this data at industry meetings, I hear things like, ‘Why the heck haven’t I heard about this before? You should be spreading the word,’” Ellsworth said. “I think other crops would see the benefits of these surveys as well, but some people fear the data will be used against them, and it takes one person committed to shepherding the process over time.”

Ellsworth is actively seeking an interested commodity group and collaborator outside the desert Southwest. 

“There was an earlier effort to expand it into Texas cotton, and a recent suggestion to take it to Northwest potatoes,” he said. “So far, we’re still looking, but we’re hopeful because it’s such a valuable way to assess IPM in agriculture.”

Growers or pest managers just being introduced to the idea might be skeptical, but participants in Arizona know the value.

“It lets us tell what we’re doing, and what’s going on the fields” said pest-control advisor Greg Hogue, who has been in the industry for 40 years. “It makes you think back about what you did, and then share that information in get-togethers like this and hear about what other people did. It’s a lot of information, and it’s valuable to us.” 

For more information, contact Peter Ellsworth.