- Author: Lee Allen
- Posted by: Gale Perez
From the Western Farm Press • March 17, 2021
By Lee Allen
Recurring, multiple-resistance species are among the biggest challenges.
Brad Hanson gets down.../h3>
- Author: Whitney Brim-DeForest
In 2017, I started getting reports of a watergrass biotype/species (Echinochloa spp.) that was difficult to control using our suite of herbicides registered in rice. At the time, I knew we had multiple herbicide-resistance in late watergrass (Echinochloa phyllopogon), so I initially just thought the resistant biotype was spreading, and had maybe gained resistance to additional herbicide modes of action. However, once I started visiting fields, it quickly became apparent that this was not late watergrass (phenotypically-speaking). It also did not appear to be barnyardgrass (Echinochloa crus-galli), although the Echinochloa species are notoriously difficult to identify, and phenotypically quite variable in...
- Author: Lynn M. Sosnoskie
Weeds compete with crops for light, water, and nutrients, which can result in yield reductions. Weeds can also interfere with crop production by serving as alternate hosts for pests and pathogens, providing habitat for rodents, and impeding harvest operations, among other impacts. Natural areas can also be impacted by weed species when they reduce aesthetics and disrupt ecosystem services. As a consequence, growers and land managers employ a variety of control strategies, including the application of herbicides, to manage unwanted vegetation.
Although herbicides can be effective tools for controlling undesirable plants, failures can and do occur. Weeds may escape chemical treatments for several reasons including: the selection...
The old saying, “Everything's fine until it's not,” comes to mind when dealing with some tough to control perennial weeds in alfalfa production during the summertime. Such was the case for an alfalfa field in the Sacramento Valley, where weed control seemed good up until mid-summer, and then it wasn't. Perennial weeds that started off small and overlooked, grew through the season, persisting through multiple cuttings, including curly dock, plantain, and nutsedge. For tough to control weeds in alfalfa fields, one needs to determine: 1) What types of perennial weeds are present, and 2) How many of them are there, to make a decision on how to manage them. These sorts of weed issues can creep up quickly in older alfalfa...
- Author: Brad Hanson
Glyphosate is one of the most widely used herbicides in the world and is extremely important in many of our orchard, vineyard, and annual crops as well as in non-crop and home situations. However, it can be confusing to understand some of the differences among various formulations of glyphosate herbicides.
I'll paraphrase a recurring extension question as “I'm trying to compare the rates and cost-effectiveness of two glyphosate herbicides. One lists the active ingredient as ‘41% glyphosate as the isopropylamine salt' and the other as 48.7% glyphosate as the potassium salt'. How do I compare these two herbicides?”
First important point, glyphosate is a weak acid...