Arizona Crop Information Site logo
University of Arizona
Vegetable IPM Updates Archive
Cooperative Extension
Kerb Registered on Leaf Lettuce (January 20, 2016)
The registration of Pronamide (Kerb) for use on leaf lettuce was cancelled almost 7 years ago. It had been the standard for weed control on all types of lettuce for 45 years and this cancellation created serious economic problems for leaf lettuce producers. As the end users, we do not see all that goes on when a pesticide is registered for food crops, especially now with all of the concern for food safety and environmental contamination. EPA required all of the data needed to register a new product which is now very stringent. Among other things, the cancer classification had to be changed from “Likely to be Carcinogenic to Humans” to “ Not Likely…” Once this was accomplished it opened up the risk cup to add leaf lettuce. A tolerance had to be established based on residue trials conducted by Dow AgroSciences and the IR- 4 Program. A tolerance of 1 ppm was established which is the same as head lettuce. Drinking water, surface water and ground water risk assessments also had to be conducted. Various other more minor requirements also had to be addressed but both US EPA and the State of Arizona have now approved the registration. No less critical in all of this has been industry support including numerous letters, meetings and phone calls from many in the industry. A group of representatives from the Arizona lettuce industry submitted a Sec 18, Emergency Exemption application that contributed to this effort. This group consisted of Steve Alameda (grower ), Bill Fox (PCA), Kevin Ford ( vegetable seed), Matt Mcguire (grower), Bruce Gwynn (Yuma Fresh Vegetable Association.) and Shelley Tunis ( Yuma Fresh Vegetable Assn.). There are few people involved with the lettuce industry in Arizona and California that were not involved with DowAgrosciences in some way to restore this valuable registration. The system was slow and expensive but it worked.

Click picture to listen to Barry'update video
To contact Barry Tickes go to:

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.

Home | Cotton | Veggies | Forages | Grains | Citrus | Crop x Crop
Insects | Diseases| Weeds | Pesticides | Economics | News | Weather | Research | Photos | Contacts | General Info.

Copyright © 2001 University of Arizona,
College of Agriculture and Life Sciences
Webmaster: Al Fournier (