See no weevil. That is the goal of the cotton grower-funded and -operated Texas Boll Weevil Eradication Program which has succeeded in eliminating boll weevils from the majority of Texas cotton acres. With the functional eradication of weevils from almost all of Texas, the program has increased the profitability of cotton production throughout the state. In spite of these successes, the battle to eradicate boll weevil in Texas is not yet won and given our close proximity to the Rio Grande Valley re-infestation is always a potential. One of the strongest backbones of the Texas Boll Weevil Eradication Program is to maintain the area free of hostable cotton after harvest until the emergence of the next year’s cotton crop. 

It is clear that weather has created a major handicap for this effort over the recent couple weeks, but growers are urged to make sure cotton stalks are destroyed and any emerged volunteer cotton is terminated as soon as fields are dry enough to do so. Since July 16 there have been 186 boll weevils caught in Jim Wells, Kleberg, Nueces, and San Patricio counties which prompted the placement of additional traps and the treatment of surrounding acres in the area. In Nueces County growers can expect higher trapping densities to be seen next growing season in the southwestern portion of the county in locations relative to where weevils were found this season.

How these weevils arrived late in the season is uncertain, but the hitchhiking of weevils on equipment being moved through the area is always a concern. Local growers who plan to move equipment north are strongly encouraged to clean and inspect equipment even if they are staying in the East Texas Maintenance Zone in the move.

There will be plenty of hostable plants in fields due to weather conditions. As fields dry and growers address that issue another new obstacle to continued progress in the eradication effort is volunteer cotton with the new herbicide technology traits. While products are available for effective control of cotton with these traits, there is concern new herbicide technology traited volunteer cotton might show up in fields where it is not expected to due to contamination in planting or harvesting equipment moving seed around. For this reason growers are encouraged to continue to scout fields for any “escapes” they might have after an herbicide treatment. Just a few hostable cotton plants can have a major impact on boll weevil numbers.

Way back in 2007, when Dr. Noel Troxclair was serving as AgriLife Extension Entomologist in Uvalde, he did an impromptu study on the consequences that “just a few” hostable cotton plants in a field could have on future boll weevil numbers. He collected the fruit from cotton plants left uncontrolled on one farm. From 2 plants 249 boll weevils emerged at one site on the farm.

He then proceeded to collect a total of 12 cotton plant samples from 5 other sites on the farm where cotton was left hostable. At least 561 weevils emerged from the 12 volunteer cotton plants that he examined on this farm and there were a dozen or so more plants that were not examined. Troxclair found that assuming a 50:50 sex ratio, a 100% survival of well-fed weevils in a mild winter climate, and an average of 150 eggs per female the weevils that emerged from this single farm represented the potential for over 42,000 eggs.

When these 12 plants are multiplied many times over by all the hostable cotton currently in our region it becomes apparent that hostable cotton must not be ignored. The potential consequences for boll weevil eradication and the continued economic viability of this crop are too great.

For more information contact our office at 361.767.5223 or on the web at http://nueces.agrilife.org/