Transgenic Herbicide Tolerant Cotton

 

Nutsedge control with Roundup Ready cotton

Annual and perennial weeds infesting thousands of acres of cotton in California remain a major stumbling block to efficient and economic cotton production. Early weed competition (first week of the crop's life) cause the greatest yield reduction while late season infestations interfere with defoliation and harvest. Weeds growing outside the crop serve as hosts for insects, mites and pathogens.

Strategies employed to control weeds can be quite costly, amounting to 40% of the total pest control costs, and also have negative impacts on the environment.

 

 
Since 1996 studies have been conducted at UC Research and Extension Centers and with grower cooperators throughout the San Joaquin Valley to evaluate both Roundup Ready and BXN (Buctril) herbicide-tolerant cotton varieties.

The trials indicated excellent control of summer annual broadleaves with herbicide-tolerant cotton varieties, including both Roundup Ready and BXN. To control grasses, grass herbicides have to be tank-mixed with Buctril. Annual morningglory, nutsedge and field bindweed can be effectively controlled with two applications of either Roundup or Buctril. Information developed through these studies provided growers the needed guidelines to adopt the use of herbicide-tolerant varieties.
 

 
Herbicide tolerant cotton has now been integrated in our cotton production system. In 2002, 50% of the upland cotton grown in California was genetically modified, either Roundup Ready, BXN or stacked gene (Bt/Roundup Ready). These varieties have reduced grower costs as much as $100 or $150 per acre. Herbicide use has been reduced and growers are now experimenting with alternative production systems (conservation tillage) to further reduce costs and improve soil and air quality. This technology has allowed growers to maintain their economic viability, and at the same time have a positive impact on the environment by reduced use of herbicides and tillage, resulting in better air quality.
 

Supporting Unit: Madera County
 
Ron Vargas, Farm Advisor - Madera County
Steve Wright, Farm Advisor - Tulare County
Bob Hutmacher, Cotton Specialist - Shafter Field Station