For the first time in 45 years, Kerb is available in Arizona and California as a liquid suspension concentrate (SC). Aqueous suspension concentrates use little or no hazardous organic solvents and are often more stable and environmentally friendly than many other formulations. This SC formulation has been used in Europe (Kerb Flo) for several years. Both formulations are available as Kerb 50W, Kerb SC, Pronamide 50 W or Pronamide SC and users must decide which to use. We have worked with both formulations for about 5 years to compare efficacy and application. When a good application is made, weed control is the same for both formulations. The active ingredient, Pronamide, is the same and there is no difference in the weed spectrum or level of weed control. Differences, if there are any, will likely be in measurement and mixing. The Kerb 50W that we have used all of these years contains 50% active ingredient per pound and is packaged in water soluble bags. The new SC formulation contains 3.3 lbs. of the active ingredient per gallon and is packaged in 2.5 gallon containers. One pound of Kerb 50W, for example, is equivalent to 1.25 pts. of Kerb SC. This conversion chart was put together by Dow AgroSciences:

The exact amount of product needed can be mixed with the SC formulation while the 1 lb. 50W water soluble bags make it necessary to mix to the closest pound. Water soluble packets improve the handling of wettable powders but it requires time and good agitation to properly dissolve the packet. Once dissolved, frequent agitation is needed to keep Kerb 50W in suspension. Some users have reported that the Kerb 50W can be abrasive to roller pumps. The SC formulation mixes well, is more stable, and does not easily settle out. As far as mixing and stability is concerned, the SC formulation is an improvement.

To contact Barry Tickes go to: btickes@ag.arizona.edu.

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.