- Posted By: Gale Perez
- Written by: Luis Espino
A new weed has been identified in California rice. Its name is winged primrose willow (WPW), and it is a weed in rice fields in the southern US. So far this weed has been identified only in fields near Richvale. The Butte County Ag Commissioner is working to make sure this weed doesn't spread to other areas. The UC Davis Rice Weed Science Project and UCCE is collecting information about its biology, possible impact and management.
Don't confuse WPW with other waterprimroses, similar weeds that are usually seen around rice fields and ditches and are prostrate. WPW habit is erect, the yellow flowers have 4 petals, and the stem has wings or membranes that run longitudinally. Unlike other waterprimroses, WPW can grow within...
- Author: Brad Hanson
... well, a new name and new uses for a familiar product anyway.
I received a notification today that Dow AgroSciences received California registration for TrellisTM herbicide for use in grapes and tree nuts.
The active ingredient in Trellis, isoxaben, may be familiar to folks who have used Gallery T&V herbicide which was registered in 1998. This is a residual herbicide that will provide several months of control for a fairly broad range of broadleaf weeds (minor activity on some grasses). For more info, go to the UC Weed RIC "herbicide susceptibility chart" and scroll down to isoxaben (Gallery) in the herbicide window or read the Trellis label...
- Author: Cheryl A. Wilen
Just a quick note about soil seed banks. If you are not familiar with the term, it is where seeds are stored in the soil until conditions are appropriate for germination or where they decompose. There are thousands of seeds in a seed bank and not all will germinate at any given time or any given set of conditions. That's one of the reasons annual weeds are a problem year after year, even if you kill the current year's weeds before they produce seeds.
If you need proof, I'm attaching a photo of a plot that was tall fescue turf for the past 5 years and there were few weeds in the plots. I then shut off off the water for a few months and the fescue died. I recently started irrigating a few plots and up came a bumper crop of...
- Posted By: Brad Hanson
- Written by: WSSA press release
The Weed Science Society of America (WSSA) recently released a series of free online training modules on understanding and managing herbicide resistance. The target audience for the five modules is consultants/field advisors/agronomists but I think any weed managers could benefit from them.
According to David Shaw, the chairman of the WSSA Herbicide Resistance Education Committee "When farmers have a better understanding of herbicide resistance and how to manage it, they can adopt proactive management programs that delay or mitigate the evolution of herbicide-resistant weeds".
The five training modules include:
- Author: Brad Hanson
Residual or soil applied (ie. preemergent or PRE) herbicides can provide many benefits to weed managers. In contrast to foliar-applied (postemergent) herbicides that only affect the weeds present at the time of the application, residual herbicides persist in the soil and have activity on weeds that germinate after the application. Depending on the chemistry of the specific herbicide, the rate applied, weed spectrum in the field, and environmental conditions, weed control may last for several weeks or months.
When performance problems arise with residual herbicides, they usually take the form of either unexpectedly short or unexpectedly long residual activity. As illustrated in the line diagram below, our goal with residual...