A new pathway for weed science at UC Davis
The weed science program at UC Davis has a long and storied history which set the program on its course to develop practical weed management options for growers. Much of the progress has been built on use of herbicides to control weeds in the wide diversity of California crops. Undoubtedly California growers have much better weed management options today than they did in 1940 or 1950 thanks to translocated herbicides like glyphosate which enable us to suppress the most difficult perennial weeds like field bindweed. Much of this progress in weed management is owed to the agrochemical industry which through private investment in weed management research, developed some very effective products. However, conditions are not static, and the status of private investment in weed research today has diminished much from what it was as recently as the 1970's or 1980's. This essay will explore some of the implications of the relationship between the agrochemical industry and California vegetable crops. Suggestions for new weed control tools will be explored.
Herbicides are different than fungicides or insecticides in the eyes of industry.
The agricultural chemical industry since the 1990s has placed much more emphasis on developing new fungicides and insecticides and less on herbicides. There are many reasons for this:
- Higher potential for injury to high value crops like vegetables with herbicides than for fungicides and insecticides, i.e., the liability exposure for registrants is higher than the value of potential sales;
- Glyphosate tolerant corn, soybean and cotton has reduced incentives for development of herbicides in major crops, and fewer herbicides are being introduced than say 30 years ago;
- Herbicides are much more likely to persist in soil and injure rotational crops than fungicides or insecticides, hence there are few potential herbicides available for vegetables.
Proof that industry has spent much more time on fungicides and insecticides is easy to find. According to the California Dept. of Pesticide Regulation data base, and using head lettuce as an example, there are 6 major fungicides, 8 major insecticides and 1 major herbicide, with “major” defined as use on more than 40,000 acres of lettuce. The average age of the fungicides is 17.2 years, insecticides 18.9 years and herbicide 27 years. With constant development of disease and insect pest resistance there is need for new products. In contrast, there has been little development of herbicide resistant weeds in California vegetables due to the integrated weed management system used in those crops.