Despite weather-related setbacks, efforts to eradicate the boll weevil from Texas cotton fields made progress in 2007.
No boll weevils were caught on more than 4 million acres of Texas cotton in 2007, says Charles Allen, program director, Texas Boll Weevil Eradication Foundation Inc. “Six large zones in West Texas caught no weevils all year long,” Allen said during the recent Beltwide Cotton Conferences in Nashville, Tenn. “The program is finishing up in the western half of the state. Statewide, weevil trap captures were down 41 percent from 2006.”
However, after going without catching a single weevil through August, the Southern Rolling Plains zone started catching weevils after tropical storm Erin passed through the area. Weevil captures increased through mid-October in this zone located near San Angelo. By December, more than 6,000 weevils had been caught in the zone and more than 390,000 cumulative cotton acres were treated.
“All indications are that these weevils moved into the zone from areas to the south or east of the Southern Rolling Plains zone,” Allen said.
Extended periods of rainy weather made efficient trap inspection and field treatment difficult in 2007. “Week after week of rain and muddy fields, particularly in the south and east Texas zones, made thorough trap inspection impossible. This resulted in undetected and untreated weevil establishment in some fields. The rain also lessened the effectiveness of treatments.”
Other weather related problems developed in the South Texas/Winter Garden zone. “As the number of fields needing treatment increased and rain continued to limit the time available each week for treating fields, a shortage of aircraft and pilots developed,” Allen said.
“Virtually all the uncommitted pilots and aircraft left the state to spray corn acreage in the Midwest due to an outbreak of grey leaf spot. Lack of available pilots and planes caused critical delays in boll weevil treatments,” he said. “While this situation was being corrected, weevil populations were building in some of the affected South Texas/Winter Garden fields. By the end of the season, boll weevil populations had increased significantly in the South Texas/Winter Garden zone.”
In spite of the weevil increase in 2007 in the South Texas/Winter Garden zone, boll weevil numbers have been reduced more than 91 percent since the program began there. At the end of the year, 65 percent of the fields in the zone had not caught a single weevil all year.
Overall, the five boll weevil eradication zones in South Texas and East Texas had a 41 percent reduction of boll weevils from 2006 to 2007.
Trap catches for 2007 by zone:
- Northwest Plains
- Northern High Plains
- Northern Rolling Plains
- Southern High Plains Caprock
- Permian Basin
- Southern Rolling Plains
- Southern Blacklands
- Northern Blacklands
- St. Lawrence
- El Paso/Trans Pecos
- Western High Plains
- Rolling Plains Central
- South Texas Winter Garden
- Upper Coastal Bend
- Lower Rio Grande Valley
Allen also reported on progress for the Pink Bollworm Eradication effort, underway in far West Texas since 2001. A combination of Bt cotton varieties, mating disruption, chemical controls and sterile insect releases has decreased pink bollworm numbers significantly in the El Paso/Trans Pecos zone.
“We saw a hot spot near Acala, Texas, about halfway between El Paso and Fort Hancock in 2007,” Allen said. “We found larvae in a few small fields.
“Overall, numbers are coming down nicely,” Allen said. Prior to 1999, the average field in the El Paso area had about 20 percent of the late season bolls infested by pink bollworms. In 2007 that figure had dropped to 0.024 percent. “We've seen a 99.9 percent reduction in the number of native moths from 1999 to 2007,” Allen said.