- Author: Brad Hanson
I was forwarded a question recently about rotating herbicide mode of actions for resistance management in vineyards and realized that the information is not always particularly easy to find. We are planning to include site of action information in the next update of the Herbicide Susceptibility Chart; however, it is not available on the current version (http://info.ucanr.org/weed_sept/).
In the meantime, I updated the T&V herbicide registration chart from a few weeks ago with herbicide site of action groups according to the Herbicide Resistance Action Committee (letter/number) and Weed Science Society of America-WSSA (number) systems. There is still some debate about the pros and cons of these two systems and it is not clear which one (or when) will become common on US herbicide labels.
Here is a link to the chart. Or click on the chart below for a pdf version.
If you are interested, here are two links that describe some of the common sites of herbicide action.