It is common to plant wheat following lettuce in Yuma and the Imperial Valley. All Three of the soil active herbicides that are used on lettuce, Bensulide (Prefar), Benefin (Balan), and Pronamide (Kerb) can cause temporary injury to wheat. Although some temporary injury is not unusual, it rarely causes losses in yield or quality and is normally not considered a problem.

Pronamide (Kerb) moves readily with irrigation water and it is normally gone by the time the wheat is planted. The Kerb label, however, specifies that a rotational interval of 12 months should be followed. A good irrigation will help move this herbicide out of the root zone and 12 months is not usually needed.

Bensulide (Prefar), and Benefin (Balan), stick to medium and fine textured soils and irrigation water is ineffective in moving them below the root zone. The rotational interval for both of these is shorter, however, than it is for Kerb. It is 4 months for Prefar and 10 months for Balan. Tillage is the best way to minimize potential crop injury from both Prefar and Balan.

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.