How the preemergence herbicides that are used on cole crops are incorporated can have a significant effect on how they work. The primary factor that effects how they should be incorporated is how strongly they adhere to the soil. Prowl incorporates well with both sprinkler and furrow irrigation. Treflan, on the other hand, is difficult to incorporate with water alone and needs to be mechanically incorporated. More than the possibility of inferior weed control, the risk of crop injury is increased if Treflan is concentrated on the soil surface and not mechanically incorporated. Typically the stems will swell, become brittle and could break off with a strong wind. Prefar adheres strongly to the soil and needs to be incorporated with a lot of sprinkler water. It does not work well if it is furrow irrigated or mechanically incorporated. Dacthal adheres strongly to the soil and also needs to be incorporated with a fair amount of water. There should be some soil moisture present when Dacthal is applied. If it is applied to dry soil it will adhere very strongly to fine textured soil and may not work well. Soil texture is important. There is several times more surface for herbicides to bind to in fine textured soil then with course textured soil.

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.