I thought I'd followup on my post last week about herbicide resistant weeds with a little more detail on our recent (and ongoing) work on glyphosate-resistant horseweed (Conyza canadensis) which is also known as mare's tail.
In 2006 and 2007, we conducted research to determine the magnitude of the glyphosate-resistant horseweed problem in the Central Valley. The sampling was focused at that time in the Fresno area but included sampling as far south as Wasco and as far north as Marysville. We published the results of the initial project in 2009 (Weed Science 57:48-53) but the work has also led to several related projects which are ongoing.
In general, we found that:
1. Glyphosate-resistant horseweed was...
FYI - Symposium announcement:
Current Issues in Vineyard Health
Date: November 30, 2010
Time: 9:00 AM - 4:00 PM
Contact: Student Services staff is available M-F, 8 a.m.-5 p.m. Phone: (800)752-0881 From Davis or Woodland (530)757-8777
Sponsor: UC Davis Extension
Location: Da Vinci Building
Address: 1632 Da Vinci Ct. Davis, CA
If you’ve ever taken target practice, you probably know that accuracy and precision are not necessarily the same things – a rifle that always shoots low and to the left of the bull’s-eye is precise but is not accurate. The same idea holds true for herbicide applications. Because the winter/spring weed control season is upon us, it’s time to think about ensuring that spray rigs and operators are set up to make precise and accurate applications. We want to make sure that we are applying pesticides on target and at the right rate (accuracy) and that our application in every pass or field is the same as the last (precision) in order to get good weed control and minimize off-target movement.
The most common causes of poor herbicide...
*This was an article that Doug Munier and I put together and tweaked for a couple orchard crop newsletters in summer/fall 2010. I thought I'd repost it here for posterity... Brad
Controlling Glyphosate-Resistant Weeds in Orchards with Rely:
Understanding the Issue and Managing the Solutions
Brad Hanson, UC Weed Extension Specialist, Davis
Doug Munier, UC Farm Advisor, Glenn, Butte, and Tehama Counties
By now, many tree fruit and nut producers in the Central Valley are familiar with glyphosate-resistant weed species. In the north Sacramento Valley, glyphosate resistant ryegrass is...
I am a Cooperative Extension Weed Specialist at UC Davis and decided to start this blog as a bit of an extension experiment. Technology changes have given us new opportunities to share knowledge and I thought I’d join in the fray – we’ll see where it leads!
Some people may not know what a CE Specialist does (I wasn’t either before becoming familiar with the UC system). In my version of the job, I conduct applied research in weed management and ecology and extend this information to farmers and other folks in production agriculture. In many other University systems, I would be a Professor with a Research and Extension appointment (I do not have a teaching appointment).
My research program currently focuses on control...