Eradication of the pink bollworm from Arizona cotton fields is proceeding as planned.
“We are having good success in eradication efforts through the Arizona Pink Bollworm Eradication Program. Each cotton-growing area is at some phase of eradication,” says Larry Antilla, director, Arizona Cotton Research and Protection Council (ACRPC). “The long-term goal is to protect and maintain the viability of Arizona’s cotton industry.”
Following the endorsement of a statewide pink bollworm eradication referendum in 2004 (by an 80 percent approval rate), the Arizona eradication program began in 2006. Arizona is the last state in the Southwest cotton belt to launch “pinkie” eradication.
The eradication program is directly funded with a grower assessment of $1.25 per bale which covers program management, monitoring, traps, and lures, plus the supervision of pheromone, insecticide and sterile moth applications. For growers of non-Bt Upland and Pima cotton, there’s an additional $32 per acre charge for pheromones, insecticides, and application costs. Growers who plant Bt cotton are exempt from the $32 per acre fee.
The production and distribution of sterile moths are paid entirely from federal appropriations.
The ACRPC is an Arizona state agency funded by bale assessments, federal funding for the pink bollworm eradication program, and by the group’s bio control program. The ACRPC receives no state general funding dollars.
The ACRPC is operating pinkie eradication according to guidelines established by the National Cotton Council’s pink bollworm eradication committee and an international technical advisory committee.
Seven central and eastern Arizona counties kicked off eradication in 2006 including Cochise, Gila, Graham, Greenlee, Maricopa, Pima, and Pinal counties.
“There is a 99.8 percent reduction in native pinkies in Area 1 since the program was launched,” Antilla says. While 156,000 native moths were captured in Delta traps in 2006, about 200 natives have been captured this year.
“The reduction figures are impressive, but finding the last few natives is often the hardest part of any eradication program,” Antilla says. “Capture numbers down to 200 natives means we’re making good progress. But remember, our goal is the last man standing.”
Eradication launched last year in La Paz and Mohave counties in far western Arizona along the Colorado River has also substantially reduced native numbers.
“Results show a near 99 percent reduction in pink bollworms in Area 2,” Antilla says. Expeditious control was largely tied to cotton farmers’ ability to plant 100 percent Bt cotton without following refuge requirements.
Growing Bt cotton without refuges was not easily attained and is a major accomplishment in itself. Antilla, along with ACRPC Chair Clyde Sharp, a Roll, Ariz. cotton grower, and others successfully lobbied a scientific panel to gain approval of 100 percent Bt use without refuge requirements.
The panel accepted the plan which was then approved by the Environmental Protection Agency (EPA). Arizona then granted a 24c exemption to the ACRPC that allowed cotton growers in the ACRPC eradication areas to forego refuges. Antilla and Sharp noted that the 24c was the result of a huge team effort and was an incredible accomplishment.
“Bt cotton produces almost 100 percent control of the pink bollworm,” Antilla says. “Bt is the most powerful tool ever developed for pinkie control when coupled with other components in the eradication program.”
A similar exemption was granted in 2007 for Southern California cotton growers through a Section 18 exemption granted by the EPA. The exemption applies to growers in the Blythe and Palo Verde Valley areas where 10,000 to 13,000 acres of cotton are planted this season.
Eradication efforts began this spring in Yuma County, an even more challenging area.
“The area is unique since it’s bi-national; the U.S. and Mexico,” Antilla explains. Contiguous cotton is grown from San Luis, Ariz. into Mexico’s Mexicali Valley. About 50,000 cotton acres are on the Mexican side of the border while about 9,000 acres of cotton were planted in Yuma County this year.
“Mexico has stepped up to the plate,” Antilla says. “The Mexican government has put in eradication dollars and so have the growers. It’s a good marriage of efforts between the two countries in addressing pink bollworm eradication.”
Eradication in Arizona is based on a four-year program per region with no extension allowed.
According to the ACRPC, the pink bollworm has been the most serious cotton pest in Arizona, Southern California and northwestern Mexico for 40 years. It is considered the most destructive cotton pest in the world. In Arizona and Southern California alone, more than 72 million acre equivalents of pesticides have been applied to control the pest with an estimated cost of $1.3 billion.
The ACRPC eradication program is based on several integral areas of control. Advocated cultural practices include timely stalk destruction and the burial of crop residue. Arizona state law establishes mandatory plow down dates for each growing area.
As stated previously, Bt transgenic cotton is highly encouraged and the ACRPC closely monitors for possible resistance. In conventional cotton (Upland and Pima) PB rope containing a pheromone dispenser applied at high rates on plants provides a mating disruption. Sprayable formulations are sparingly applied.
Another control mechanism is the 49 million sterile male and female moths released by air weekly over Arizona cotton fields. The moths are reared at the USDA-ARS pink bollworm sterile moth lab in Phoenix owned by the state of California. The moths’ diet contains a red dye to distinguish them in traps from native moths. Sterile moths from the same lab are used in eradication efforts in New Mexico and West Texas.
California cotton growers have used sterile moths and pheromone trap monitoring for more than 40 years to keep pinkies out of the San Joaquin Valley. California cotton growers financed the pink bollworm rearing facility in Phoenix. Sterile pink bollworms are flown weekly to the San Joaquin Valley to drop over the Valley’s cotton fields.
Sterile moth technology is based on sterile moths breeding with any natives, resulting in the deposition of non-viable eggs.
At what point should Arizona be declared eradicated of the pink bollworm? Determining that procedure is the responsibility of the National Cotton Council’s technical advisory committee chaired by retired USDA-APHIS Entomologist Robert Staten, Phoenix.
“We will establish a system where functional eradication could be announced,” Staten says. “Full eradication could be declared a year after the eradication activities are ended. Final decisions must be biologically based.”
Texas, New Mexico update
Pink bollworm eradication continues in 15 West Texas counties. “This year we’ve only caught eight native moths,” says Edward Herrera, El Paso/Trans Pecos zone manager with the Texas Boll Weevil Eradication Foundation Inc. (TBWEF). The foundation is charged with eradicating boll weevils and pinkies.
Herrera credits the triple approach of sterile moth releases (12 million daily), Bt cotton, and pheromones for gaining ground on native pinkies. Insecticides are not required now. West Texas eradication began in 2001.
In New Mexico, the news is even better — no native captures this year. Fifteen natives were caught in traps last year.
“We’re very pleased. I’ve been keeping my fingers crossed because it’s been a long road,” says Joe Friesen, program director of the South Central New Mexico Pink Bollworm Control Committee, Las Cruces. “We’re so close now to the zeroes. We want it this year.”
The three counties in eradication include Dona Ana, Luna and Sierra. Currently sterile moths are the single control method. New Mexico kicked off pinkie eradication in 2002.
Of the 14,846 acres of New Mexico cotton this year, 11,428 acres are Bt cotton and 3,418 acres are Pima and non-Bt short staple. The natives found last year were all in traps. Boll cutting hasn’t yielded a native moth in three years, Friesen says.