Riata Roundup Ready Helps Widen Rotation Options

ROGUING IS a term not often heard today from cotton producers on the West Side of California's San Joaquin Valley.

The term implies a scarcity of weeds requiring simple remedial action — like going into a field and chopping out rogue weed plants here or there.

There is hardly a shortage of weeds where surface canal and furrow irrigation water scatter weed seeds like sand particles from a handful of desert sand tossed into 40-mile per hour gale.

Kings County, Calif. cotton producer Bill Stone uses the term rogue to describe part of the determined efforts at Stone Land Co. to keep weeds from invading cotton fields and other crops. He has a disdain for such exotic weeds as citron pie melon, a weed left over from the days Bill and his father, Jack, grew watermelon seeds at Stone Land Co. near Stratford, Calif.

“You don't want that to get started,” says Bill. “I found a single plant this year in cotton, and we went in and rogued it out. You can find it on ditch banks. Workers do not like to take it out. They think it will produce watermelons and seeds from it get in ditch water.”

The Stones are pilots and they have long searched for rogue weeds from the air. That is how the pie melon weed was spotted. They also look for annual morningglory, field bindweed, velvetleaf and other weed escapes from the air.

“We treat the perennials with Roundup® herbicide and chop out the annuals,” he said.

The Stones have long had an aggressive chemical and hand hoeing weed control program, but Bill says it has never been enough. “We never seemed to be winning the battle,” he said, despite their using hoe crews and a stable of effective herbicides and even tailoring their crop rotation to avoid heavy weed pressure.

“We shied away from tomatoes and did not like to plant cotton back to back on the same field because of weeds,” said Stone.

However, that has changed with the introduction of some new weed control technology. The first is Shadeout, a newly introduced herbicide primarily for nightshade control in processing tomatoes. The other is Roundup Ready® cotton, specifically Riata, a herbicide-tolerant Acala cotton from California Planting Cotton Seed Distributors.

This is Stone Land's fourth season with Riata and 2,600 of the farm's 4,200 cotton acres are planted to the variety. “There is no good reason why it all should not be in Riata other than we are cautious with new technology, and we are still learning how to best use the herbicide-resistant technology,” said Stone.

“We also like some of the non-Roundup-Ready varieties like Ultima, Maxxa GTO and Phytogen 72. We grow all approved Acala varieties.”

Stone is chairman of the San Joaquin Valley Cotton Board (SJVCB), which held up approving Roundup Ready cotton in California until the transgenic varieties went through the board's testing program, even though parent varieties were approved varieties.

This state-mandated testing program is designed to ensure approved varieties meet Acala lint and yield standards.

“I was excited about the new technology when it came along and eager to try it,” said Stone, who served for many years as board vice chairman before stepping into the chairmanship two years ago.

However, Stone and the other board members wanted to make sure the transgenic Acalas remained true to their high quality lint heritage.

Riata is the first Roundup Ready Acala and although its parentage is the widely planted Acala Maxxa, Stone said it is a noticeably different-looking cotton.

However, as an approved variety with Acala-quality lint, Riata Roundup Ready gained quick, widespread acceptance in the San Joaquin. Acala lint typically brings a five to seven cent per pound premium over other U.S. upland cottons and, in this market, that is critical. The board did approve testing of the Roundup Ready technology in non-Acala varieties early on, and many growers tried it. However, acceptance grew much wider when the first Roundup Ready Acala was introduced.

“It is a great technology, and for the first time I believe our fields are becoming cleaner each year rather than seeing weeds increase each season despite our best efforts before Riata came along,” said Stone.

Stone figures his hand-weeding costs have been cut in half from $20 per acre to $10 using Riata. Those are not very big numbers compared to others on the West Side where hand-hoeing costs can run $50 or more per acre. It is testimony, however, to the tenacious efforts of the Stone family to keep weeds out.

While Stone believes Roundup Ready cotton is cleaning up fields and lowering costs, just as important to him is that weeds become less of a factor in rotation decisions. Besides tomatoes and cotton, Stone Land also produces wheat, garlic, garbanzo beans and cantaloupes.

He uses the Roundup over-the-top until the fifth-leaf stage as well as a post-directed. “What we do is spot treat at lay-by with a hooded sprayer, typically for control of nutgrass (purple nutsedge),” he said.

From the air, the effectiveness of Stone's weed control program is very evident. Stone spies increasingly less nightshade in Riata cotton fields.

“One nightshade plant in a field can produce enough seed to infest an entire field so we look very closely for them,” said Stone.

The next big hurdle he'd like to see transgenics clear is herbicide-resistant Pima. “We are getting a lot of pressure on the cotton board to come up with it,” he said. This year more than 200,000 acres of the valley's 900,000 acres are planted to Pima and that will likely grow next season. There are Roundup Ready Pimas in several breeding programs, but breeders say it is much more difficult to get the herbicide-resistant genes into ELS cotton than upland. It may be awhile before Pima Roundup Ready is available commercially.

“Give us transgenic cotton that controls lygus, spider mites or armyworms” and the interest would be just as great as it has been with the Roundup Ready Acala Riata, said Stone.

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