Iowa State University

Herbicide Junkies   
by Bob Hartzler

July 6, 2006 - Valent recently mailed postcards (shown below) promoting the use of lactofen (Cobra/Phoenix) as a 'vaccine' for white mold and sudden death syndrome in soybean. Research has documented that postemergence applications of lactofen can increase the levels of phytoalexins in soybeans, compounds involved in a plant's defense against diseases. However, the effectiveness of lactofen in suppressing white mold has been inconsistent, and there is little data supporting protection against sudden death syndrome. Finally, there is no published research documenting changes that 'positively impact soybean health and performance' following applications of lactofen, or any other herbicide.

The article title is not intended to imply that Cobra or Phoenix are 'junk', but rather is a reference to the syringe on the front of the postcard.

Once again I appreciate the vigilince of the Missouri agronomist (those are his scribbles on the text of the card) who forwarded this postcard to me for entry into the Hall of Shame .

Prepared by Bob Hartzler, extension weed management specialist, Department of Agronomy, Iowa State University