- Author: Brad Hanson
It's that time of the year when I try to update the list of herbicides registered for use in California orchard and vineyard crops. The attached version has all the updates that I have been made aware of by my industry reps during the year. However, I have not done my end-of-year-herbicide-label-reading-marathon yet so it may change slightly over the next few weeks once I do that. Over the next few weeks, I'll try to discuss some of the more important changes in the T&V herbicide landscape.
Today, I'll focus on what could be important news for vineyard weed managers, registration of a new active ingredient for grape vineyards. Flazasulfuron (trade name: Mission Herbicide) was registered in California by ISK Biosciences this year.
Flazasulfuron is a sulfonylurea herbicide (aka a "Group 2" or "Group B" herbicide). The mode of action is inhibition of the enzyme acetolactate synthase (ALS) - this is the same mode of action as rimsulfuron (Matrix, Pruven) that is currently registered in grapes.
Unfortunately, I don't have any first-hand experience with flazasulfuron so it's tough to know exactly what to expect. I do recall seeing research presentations at a Western Society of Weed Science meeting a few years ago and being impressed with the nutsedge and grass control data that I saw and hoping that we'd be able to evaluate it here eventually. Because flazasulfuron is also registered as Katanain some turf situations (other states and countries), I'd imagine it has some pretty specific grasses that it either works on or doesn't work at all.
The only UC weed scientist that has seen it it grapes (as far as I know) is Kurt Hembree (UCCE Weed Science Advisor in Fresno County). Kurt indicated that he hadn't seen flazasulfuron on a wide spectrum of weeds but that it did a good job on barnyardgrass, pigweeds, and fleabane and a few others. So, it sure sounds promising!
Absent any first-hand information, I'll share some info from the label.
- "Mission is a selective herbicide for preemergence and postemergence control of certain broadleaf weeds and grasses in grapes"
- "absorbed through the root and foliage of plants"
- application rates of 2.14 to 2.85 oz product per acre
- the weeds controlled list has quite a few grasses and broadleaves as well as yellow nutsedge that may be important to some vineyardists.
I'll also attach the label and a marketing flyer at the bottom of the post. I'm looking forward to seeing (and hearing) how this new herbicide performs in California vineyards over the next few years in comparison to the current standard herbicide programs.