Dow AgroSciences has received U.S. Environmental Protection Agency (EPA) and California Department of Pesticide Regulation approval for Kerb SC herbicide use in leaf lettuce.

“This is an incredibly important new label for leaf lettuce growers,” says Jesse Richardson, Dow AgroSciences field scientist for southern California and Arizona.

“No other herbicide controls as many weeds in lettuce as Kerb.”

Richardson adds, “Kerb has been the standard for efficacy for decades. Lettuce growers typically grow both leaf and head lettuce so this will allow them to use Kerb across all lettuce acres.”

Kerb was already registered on head lettuce, endive, escarole, and radicchio greens.

The new label marks the return of leaf lettuce to the label. Leaf lettuce was removed from the Kerb label in 2009. Then, EPA changed the method by which tolerances were determined in lettuce.

As a result, head lettuce remained on the label, and leaf lettuce required new tolerances be established. Dow AgroSciences began the process of regaining the leaf lettuce label immediately.

Richardson explains, “We conducted state-of-the-art toxicology research that resulted in cancer reclassification to ‘Not Likely to be Carcinogenic to Humans’, performed an innovative series of residue trials that now allow 25-35 day pre-harvest intervals at lower use rates for baby greens, and did a complete overhaul of the risk assessment to incorporate these changes.”

Dow says these efforts involved strong advocacy by the IR-4 Project, Western Growers Association, California Leafy Greens Research Board, University of California, Yuma Fresh Vegetable Association, University of Arizona, and USDA-ARS.

Dow continued to invest significantly in Kerb trial work. A ‘split shot’ supplemental label was issued in 2012, allowing split applications of Kerb on head lettuce. The label will now apply to leaf lettuce as well.

Also in 2012, Dow reformulated Kerb by switching from water soluble packets to a suspension concentrate. The new formulation makes applications and mixing easier which today the company says is the preferred formulation in the produce industry.

Dow says refer to the Kerb label for application information, including rates, the method of application and application timing, pre-harvest intervals, and re-entry intervals for leaf and head lettuce.