What Monsanto has been referring to as enhanced Roundup Ready cotton will now be called Roundup Ready Flex, according to company representatives speaking at the Monsanto-Allendale Planting Co. Technology Field Day in Shelby, Miss.
“Farmers have been telling us that the thing they liked best about the new Roundup Ready was its increased flexibility,” said Kent Croon, cotton technical manager for Monsanto’s U.S. Markets Group. “So we decided to put it in the name.”
Roundup Ready Flex cotton, which is derived from a new transformation event, can be sprayed over-the-top further into the growing season than the current generation of Roundup Ready cotton. In the latter, glyphosate formulations must be post-directed under current Roundup Ready varieties after the fourth-true-leaf stage of growth.
“Tests at locations like Allendale here in Shelby are showing that Roundup Ready Flex has complete crop tolerance,” said Croon. “We have sprayed these plots four times with up to 78 ounces of Roundup UltraMax with no vegetative damage to the plant.”
Croon said that Monsanto believes that farmers generally will be able to spray Roundup UltraMax over-the-top of Roundup Ready Flex cotton through lay-by rather than having to change to a post-directed sprayer at the fourth true leaf.
That doesn’t mean that farmers can park their post-direct spray rigs for good, according to Croon.
“The need for post-directing will not go completely away,” he said. “There will be times when farmers will want to spray under the plant to get weeds down in the canopy that aren’t easily reached with over-the-top sprays.”
Farmers should also see excellent control of weeds like morningglory, teaweed, hemp sesbania and barnyardgrass because of the tolerance of Roundup Ready Flex to higher rates of Roundup, he said.
“Timely applications of Roundup will still be critical,” said Croon. “Farmers will continue to achieve their best control by spraying weeds when they are small.”
Since its introduction in 1997, Roundup Ready cotton has become one of the most widely adapted technologies ever. Monsanto estimates that 88 percent of the cotton acres planted in Mississippi in 2002 contain one or more of its transgenic traits.
Across the U.S. Cotton Belt, 69 percent of the 2002 acres contain one or both of the currently registered Monsanto transgenic traits, down slightly from 71 percent in 2001. U.S. farmers planted 79 percent of their soybean acres with Roundup Ready and 27 percent of the corn acres with one or more Monsanto traits.
Croon said Monsanto anticipates that it will receive registration for and launch new varieties containing both the Roundup Ready Flex and Bollgard II genes in 2006.
Growers attending the Monsanto-Allendale Technology Field Day heard that they may not have to wait nearly as long for the registration of Monsanto’s new Bollgard II cotton technology.
“Bollgard II is much better on all caterpillar insects than Bollgard and both are better than conventional varieties,” said Blake Layton, Extension cotton entomologist with Mississippi State University, who spoke to growers at the field day.
The second generation of cotton genetically altered by Monsanto scientists to express the Bacillus thuringiensis gene, Bollgard II contains two Bt genes – Cry 1Ac and Cry 2Ab – which broaden the control spectrum for the technology.
“The second gene, Cry 2Ab, works in a different place in the gut of the target insect,” said Walt Mullins, Bollgard technical manager for Monsanto. “We have times when we have significant infestations of bollworms in Bollgard cotton because we have lower expression of the gene in the reproductive parts of the plant.
“Bollgard II is designed to improve activity on bollworms and also improve the spectrum of control by placing two genes in the plant. It will also provide us with better resistance management tools.”
“We often have to spray Bt cotton for fall and beet armyworms and soybean loopers,” said Layton. “In some of our tests, we’ve counted high numbers of beet armyworms in DPL 50 and DPL 50B plots, but none in the Bollgard II plots.”
Mullins said Monsanto anticipates receiving registration for Bollgard II sometime this fall. If registration is received, a limited number of varieties containing the Bollgard II gene and a limited amount of seed will be available for growers in 2003.