Posts Tagged: weeds
UC farm advisor outlines problems posed by invasive species
Faber said invasive species are being introduced at a rapid rate around the world, and are primarily spread by humans.
He differentiated between non-native plants that are beneficial, such as avocados and citrus, and invasive plants that have been accidentally introduced into an ecosystem where they run rampant.
"An invasive species is something out of place and out of control," he said.
Fresno State report confirms state’s farmers apply water efficiently
Fresno State press release
Claims that California farmers are wasteful and inefficient in managing their water supplies are inaccurate, according to a new report released by Fresno State's Center for Irrigation Technology.
The study is the culmination of a yearlong effort by irrigation experts to update the 1982 University of California Cooperative Extension report “Agricultural Water Conservation in California with Emphasis on the San Joaquin Valley” by David C. Davenport and Robert M. Hagan.
The new study concludes that the 1982 report correctly framed the potential for agricultural water-use efficiency, and many of its findings are still relevant 30 years later.
Time to plan your yellow starthistle weed attack
Weeds, weeds, weeds! Have you noticed? This has been a banner year for weeds. Puncturevine where I’ve never seen it before. Garden soil covered with common purslane (at least it’s good in salads). And solid stands of yellow starthistle everywhere!
What can be done? First of all, identify your weeds. Different weeds require different treatments. Is it an annual or perennial? Does it propagate by wind-blown seeds or by runners? The University of California Integrated Pest Management website, has weed-identification guides that are fun and easy to use. The website also offers treatment guidelines.
In the California foothills, yellow starthistle (YST) is perhaps the most common weed of concern. It impacts much of our open space - agricultural and rangeland - and intrudes into our neighborhood landscapes. Yellow starthistle currently infests more than 15 million acres of land in California. Not only does it prevent recreational use, like walking or hiking, but it chokes out native grasses and wildflowers. It is also poisonous to horses, causing a neurological disorder called "chewing disease” which can be fatal once symptoms develop.
That said, yellow starthistle can be hand-pulled at any time in its lifespan. In its present dry and spiny stage, pulling the weeds can inflict pain, so be sure to wear gloves. Double-bag the plants and burn them later in the fall.
There is a fairly new herbicide (2009) on the market from Monterey Chemical called Star Thistle Killer.
Local pest control companies are also available to provide a one-time herbicide application for yellow starthistle. For more information, go to the Central Sierra Cooperative Extension website or call the Yellow Starthistle Leading Edge Project in the UC Cooperative Extension office at (530) 621-5533 or (209) 533-6993.
Information adapted from the University of California Integrated Pest Management Program and from “Yellow Starthistle: Brief Homeowner Information Sheet” by John E. Otto, Amador County Master Gardener.
Also see the following video on yellow starthistle control.
YST Homeowner Handout
RebeccaYST
Are weeds taking over your garden?
My calendar says November but the weeds in my garden think it’s spring. That nice rain last month followed by warm, sunny days has prompted them to grow like, well, weeds and that’s not good news for my winter crops.
What’s a gardener to do?
Like so many other gardeners, I turned to the folks at the UC Davis Weed Science Program. Housed in the UC Davis Department of Plant Sciences, the “weeders” are experts at helping growers and gardeners improve plant production by controlling weeds.
Which tools work the best in which situations? Here’s a quick overview, courtesy of Cooperative Extension Specialist Tom Lanini, who specializes in weed control in vegetable crops.
Mulches – Researchers test them all – plastic, bark, wood chips, other porous material, even what they call live mulches like clovers and fava beans. Mulches block light, which weeds need to grow. “I think mulches can be the best organic option for fighting weeds, especially for vines and trees,” Lanini says. Mulches are also a key weed-fighting component in organic strawberry and many other crops.
Organic sprays – Coverage is the key. “No matter what type you use – oils, soaps, acids, etc. – if you don’t spray-to-wet, 100 percent coverage, the weeds will grow back,” Lanini says. Temperature and the age of the weed matters too. Apply in temperatures above 75 degrees when weeds are very young – about a week old – for best results. Broadleaf weeds are easier than grasses to control with sprays.
The most effective organic spray Lanini has found so far is good old-fashioned vinegar, the kind you use to make pickles. The trouble with that is, the FDA has yet to approve it for controlling weeds. “You can eat it, but can’t spray it on your weeds,” as Lanini says. There are herbicides with vinegar as their active ingredient, but they are much more costly than household vinegar.
Flamers – These propane-fueled devices quickly raise the temperature of the weed to more than 130 degrees, rupturing its cell membranes. Grasses are hard to kill by flaming because the growing point is protected underground. Flamers require quite a bit of fuel, which can be costly.
Solarization has become an important method of weed and disease control in organic desert vegetable crops. In this system, four to six weeks of solar heat under clear plastic film will kill weed seeds and pathogen propagules.
Cultural practices are extremely important in all vegetable crops especially in organic crops. Crop rotations result in shifting environments that do not favor any one weed. Use of preplant irrigation followed by shallow tillage, or flaming is a very effective method of reducing the potential weed infestation during the crop cycle.
Weeding and thinning by tool or machine is a time-honored solution. Never underestimate the value of a hoe.
You can read more about the UC Weed Science Program here and access the Weed Research and Information Center web site here.
For more detail on weed management for organic vegetable crops, Click here.
Entomologists profiled in LA Times
Reporter Amina Khan with the LA Times profiled husband-and-wife entomologist team Christina and Mark Hoddle of UC Riverside (Mark is also a UC Cooperative Extension entomology specialist). The pair travel the world seeking parasitoids that can serve as biological control to invasive California pests and then test the results at the Center for Invasive Species Research at UC Riverside. "Bugs don't take weekends," Christina Hoddle told the reporter, "so neither do we."
Weed threatens rice-growing areas
Heather Hacking, Chico Enterprise Record
Photos and more details about the weed are also available from Luis Espino on the UC Rice Blog.
Autumn is for Apples: An Interview With Carol Fall
Jennifer Jewell, aNewsCafe.com
As apple season approaches, this article examines the Trinity Heritage Orchard Project through an interview of Carol Fall, program representative for UC Cooperative Extension Trinity County. The project has identified and mapped century-old apple trees from Gold Rush-era homesteads that are now on public lands and available for gleaning. Fall also evaluates how fruits of these heirloom varieties are best picked and used—whether for baking, cider-making, eating fresh or storing for winter months—and takes cuttings from the most significant varieties to plant elsewhere in the community. The article says Fall will provide apple samples Oct. 8 at Weaverville's annual Salmon Festival.
Weed day revisited on Capital Public Radio
In the 8-minute segment, which runs from about 23:50 to 31:30 in the hour-long show, Hanson outlined Cooperative Extension weed management research.
"Weeds are a tremendous problem for farmers in every cropping system," Hanson said. "In contradiction to some other pests, weeds don’t spike. They are a constant problem. Farmers are spending money on weed control and trying to minimize productivity declines from weeds competing for water, fertilizer and sunlight."
Hanson said much of UC's weed research looks at chemical control, the approach used by 85 percent of farmers.
"We try to find the most efficient rates, most effective chemicals, and the least environmentally damaging products," he said.
Callison seemed intrigued by the fact that weed seeds can lie dormant in soil for years and even decades.
"It is said, one years seeding is 10 years weeding. That’s probably an underestimate," Hanson said.