DAVID Heering, technical manager for Roundup herbicides at Monsanto was cited as saying that farmers who opt to apply a glyphosate-based herbicide other than Roundup Ultra or Roundup UltraMax over the top of their Roundup Ready cotton run the risk of injuring their crop or reducing yields.

He adds that while that might sound like a ploy to sell more Roundup Ultra or UltraMAX, Monsanto representatives say their studies show that using other glyphosate herbicide formulations -- including their own -- can produce less than desirable results in Roundup Ready cotton.

"We were interested in labelling other Monsanto glyphosate formulations for use in Roundup Ready cotton. But, all of our tolerance and gene equivalency data was based on applications of Roundup Ultra and UltraMAX.

"So, we made a commitment to look at other formulations in combination with surfactants to evaluate crop safety. The results of our research demonstrated that addition of surfactant to various formulations of glyphosate could result in significant vegetative injury compared to Roundup Ultra or Roundup UltraMAX applied alone.

"Based on these results, Monsanto is not willing to label and promote Roundup Original or other glyphosate formulations that require the use of surfactant for use in Roundup Ready cotton."

Heering was further cited as saying that the Monsanto representatives, who conducted the study at numerous locations across the Cotton Belt in 2000, observed visual injury as high as 59 percent leaf speckling when additional surfactant was added to Roundup Ultra, Roundup UltraMAX and other glyphosate formulations.

In another portion of the study, the scientists saw a shift in fruit retention and a yield reduction with the addition of a non-ionic surfactant compared to plots that were sprayed with Roundup Ultra or UltraMAX alone.

Heering was quoted as saying, "We did not see a yield reduction in every location or with every glyphosate formulation or surfactant. When testing a formulation by surfactant and by environmental interaction, it becomes difficult to predict when the problems will occur.

"Based on those findings, we decided we could not label and promote products that might be used with surfactants for application over-the-top of Roundup Ready cotton."

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