It's been a good year for boll weevils — unless you happen to be one. Entomologists and Boll Weevil Eradication personnel in New Mexico, Oklahoma and Texas report significant reductions in boll weevil numbers, following a cold winter and several years of a concentrated effort to eliminate the pests as an economic factor in Southwestern cotton production.
In Texas, Boll Weevil Foundation, Inc. program director Charles Allen, says several zones will be considered suppressed following this year's efforts. Several others could be classified functionally eradicated and one, the Southern Rolling Plains, will be classified eradicated.
“We found no weevils all summer in the Southern Rolling Plains,” Allen said recently at a Gulf Coast Cotton Production Seminar in Corpus Christi.
Allen says the El Paso/Trans Pecos zone could be considered functionally eradicated. “We've achieved a 99.8 percent reduction from where we started,” he says. The Rolling Plains Central zone likely will earn a functionally eradicated status, as well.
Other zones that have been active for several years are approaching suppression as newly established zones begin the process.
“Overall, it's been a good program,” Allen says. “We may see other zones become active soon. The Upper Coastal Bend plans a referendum at the end of 2002. Northern Blacklands growers and landowners have met to develop a budget and create a steering committee.”
Allen says the St. Lawrence zone has reduced weevil numbers with a voluntary suppression program, but growers there may not be interested in establishing an active eradication zone because of the current state of cotton economics. A similar situation exists in the Lower Rio Grande Valley.
Allen says any effort to eradicate boll weevils in the Valley would have to include Mexico. “USDA would negotiate with Mexico to assure cooperation,” he says. “They have already done that in the El Paso/Trans Pecos zone. And Mexican farmers south of the Arizona border have already eradicated the pest.”
It's been a good investment, says John Robinson, a Texas A&M agricultural economist stationed at Weslaco.
He says grower costs average $23.14 per acre in the Coastal Bend zone. When the program reaches the maintenance stage, cost will drop to $5 per acre.
Benefits may top $75 per acre, considering increased yield and reduced spray expenses.
“Analyses indicate a 7 percent yield gain,” he says. “At that rate, and 52 cent cotton, yield gain nets $43.79 per acre. Total benefit would be $43.79. That's almost $3 returned for every $1 spent on the program.”
But Robinson says yield advantages in the Coastal Bend beat that 7 percent mark.
“We're seeing closer to a 24 percent advantage,” he says, “and we can't explain the difference other than the Boll Weevil Eradication Program.”
At a 24 percent yield gain, program benefits hit $75 per acre. “That's a $6.40 benefit for each $1 spent on the program,” he says.
“Any region that does not eradicate the boll weevil will find itself in a competitive disadvantage” Robinson says. “Most of the country has eradicated the weevil. It's a good investment.”
New Mexico also is declaring victory against the boll weevil as growers reach the tail end of a 10-year effort to eradicate the pest.
“Farmer-run eradication programs are now in place throughout New Mexico,” says Jane Pierce, an entomologist with the New Mexico State University Agricultural Science Center at Artesia. NMSU researchers have been developing pest management programs to suppress boll weevil populations and lower eradication program costs.
Researchers found that slight changes in timing of planting, coupled with clearing nearby fencerows of weeds, had a powerful, lethal effect on the weevil's ability to grab a foothold. Where boll weevils did get established, these management techniques reduced yield losses and kept insect populations low.
“Anything that can be done to reduce boll weevil populations will lower eradication program costs,” says entomologist Carol Sutherland with the NMSU Cooperative Extension Service. Fifteen years ago, boll weevils crossed onto the rugged Texas High Plains and soon began an assault on New Mexico farms.
“The threat was real and serious,” says Pierce, who early on championed the state's suppression efforts and authored a series of guides on boll weevil control. “The cotton industry in much of New Mexico would have gone out of business.”
According to the USDA's Agricultural Statistics Service, the state's producers harvested 67,000 acres of cotton last year worth an estimated $26 million. Basically it's a matter of numbers.
“The boll weevil has a tremendous reproductive rate, producing a generation every 16 days,” Pierce says. “Many other insects take about 30 days.”
Over the course of a season, that means twice as many generations and a tremendous difference in numbers. “One breeding pair of weevils in the spring could result in over a trillion by the end of the season,” she said.
The first boll weevil was trapped in 1991 in eastern New Mexico's Lea County. In the following years, populations surged, causing severe economic damage and threatening viability of cotton production in the entire state.
Pierce is working with a Phoenix-based group of USDA researchers on a project that examines various formulations of malathion in microencapsulated formulations.
“The aim is to reduce the number of applications,” Pierce says. “We're looking for longer residual activity so it will last two weeks, instead of one, which cuts the number of applications in half.”
If the project is successful, it will slice application costs in half and save about $30 million across the Cotton Belt each year.
Oklahoma, after three full years and a fall diapause, is closer to eradication than officials expected, says Bill Massey, assistant director and environmental specialist with the Oklahoma Boll Weevil Eradication Organization (OBWEO).
“I think we're in excellent shape,” Massey says. “A more normal winter last year helped bring weevil numbers down, and the eradication program is beginning to have a significant impact.”
Massey says weevil counts for 2001 have been from 95 percent to 98 percent lower than in 2000. “We saw a lot fewer weevils coming out last spring and we sprayed about one-fifth as much as we did last year, a 1.4 spray average compared to 5.4 in 2000.” Fewer sprays meant less money for chemicals and application.
“Another normal winter and weevil numbers will make another significant drop next spring,” Massey says. “We caught no weevils in northern Oklahoma this year. We probably will go into confirmation in 2002 in that area and hope to be eradicated the following year.”
Massey says yields are up for Oklahoma cotton farmers this year. “Part of that is the result of Mother Nature,” he says, “but the eradication program also helped.”
Ray Frisbe, head of the Texas A&M entomology department, says the weevil has cost U.S. cotton farmers $17 billion.