ABILENE, TEXAS - Texas Commissioner of Agriculture Susan Combs recently declared the Northern High Plains boll weevil eradication zone to be suppressed. Consequently, growers may be using fewer pesticides to manage their crops.
Data presented at the Beltwide Cotton Conferences shows that, depending on the year, treatments for boll weevils constituted from about a third to almost a half of the insecticide applications made to cotton crops since the mid-1980s. Only one other cotton pest has accounted for as much insecticide as the boll weevil, the cotton bollworm/tobacco budworm complex. The development of transgenic varieties of cotton has targeted these worms.
But the boll weevil cannot be controlled through the new cotton varieties, and it has no natural predators to speak of. So cotton producers have relied on insecticides to do the job. With the virtual elimination of the boll weevil, insecticide usage has dropped dramatically.
Once cotton producers began eradication on the Northern High Plains, ultra-low volume malathion applications were used in combination with pheromone trapping and integrated pest management methods.
Since the program began in the fall of 2001, the amount of malathion used to control boll weevils has dropped by 99.8 percent, according to Texas Boll Weevil Eradication Foundation records. In the Plainview area, pesticide usage was virtually eliminated.
As the weevil disappears from the High Plains, cotton growers are working with integrated pest management specialists to find ways of controlling the remaining pests with minimal use of insecticides. Growers should be able to reduce pesticide use by 75 percent, according to Tom Fuchs, statewide IPM coordinator for Texas Cooperative Extension.
Fuchs said the Southern Rolling Plains, the area around San Angelo that was declared functionally eradicated in September 2000, reduced pesticide use from 75 percent to 80 percent most years since the declaration.
Dr. James Leser, extension entomologist in Lubbock, said the High Plains is seeing similar results.
"We have seen a 67 percent reduction in insecticide use for bollworms, beet armyworms and aphids the last couple of years, which I attribute to less spraying for weevils," he said.
The boll weevil's dominance on the list of most treated cotton pests is over, and it will drop completely from the list when eradication is complete.