Wright told the recent California Weed Science Society annual meeting that about a third of the cotton and corn acreages in the state were planted to herbicide-resident varieties, primarily Roundup Ready varieties in 2002.
That was about 175,000 acres of cotton and 150,000 acres of corn. In 1997 there were only 100 acres of Roundup Ready cotton planted in the state.
For the remainder of the U.S. Cotton Belt, the adoption rate is 70 percent.
It will likely reach that level in California when the new, wider application window technology is introduced in cotton. This will give growers more time to apply the Roundup over the top of the plant without damaging the crop. Right now the cutoff is the four-leaf stage. The new "flex" technology will extend that window to 12 to 14-node cotton.
Adoption of the technology also has been limited by the short lists of cotton and corn varieties available with the herbicide-resistant biotechnology.
Wright said that may work to reverse the increasing-use trend of biotechnology in cotton in the short term. He predicted that the use of Roundup Ready technology will decline next season with growers switching to significantly higher yielding varieties.
Non-herbicide resistant Phytogen 72 has consistently outyielded (15 to 18 percent) the most dominant Roundup Ready Acala cotton in the valley, Riata RR, according to Wright and he predicts Phytogen 72 acreage will grow at the expense of Riata.
"You are talking about a 200-pound yield increase in our area and that means producers have significant additional income to deal with weeds without paying for the Roundup Ready technology," said Wright.
Wright said there is a well-stocked pantry of herbicides available other than glyphosate to deal with weed problems, not the least of which is Staple, the very effective over-the-top herbicide for control of one of cotton producers’ toughest weeds, nightshade.
Plus, he said with a smaller overall cotton acreage producers are planting on "cleaner" fields.
Roundup Ready technology will continue to find a niche in weedy fields which would require hand weeding and added cultivation without the over-the-top broad spectrum weed control glyphosate provides. It is also finding favor with producers growing ultra-narrow-row and twin-line cotton which are not conducive to cultivation.
"Right now the biggest thing that is limiting the use of herbicide-resistant technology in corn and cotton is that the technology is not available in Pioneer corn varieties, in Pima cotton and in Acala varieties like Phytogen 72," said Wright.
When those varieties are sold with the RR technology, adoption of herbicide-resistant technology will quickly reach the 70 percent level in California.