UCCE Humboldt - Del Norte Counties
University of California
UCCE Humboldt - Del Norte Counties

Posts Tagged: invasive weeds

Unwelcome weed 'stinkwort' spreading quickly in California

Invasive weed stinkwort, Dittrichia graveolen, can spread rapidly on overgrazed land, river and stream banks and roadsides.
UC Cooperative Extension experts are advocating for aggressive control of invasive stinkwort to prevent it from becoming an established California weed, reported the Sacramento Bee. Joe DiTamaso, UCCE specialist in the Department of Plant Sciences at UC Davis, said he believes CalTrans will have to treat stinkwort as an invasive of high and unique concern if it has any hope of controlling its spread.

Stinkwort made its first California appearance in 1994, but remained quite rare until the mid-2000s, when it began spreading rapidly. Stinkwort is now found in 36 of the state's 58 counties, particularly along roadsides.

"If it gets a major foothold and produces millions and millions of seeds, then the seedlings will grow and they can form a carpet," DiTomaso said. "Then it would block light and prevent the growth of more desirable species – like native plants. It will out-compete them, and that is a concern."

Another troubling aspect is that the weed has been seen in vineyards, said John Roncoroni, UCCE advisor in Napa County, a weed science expert.

"I've seen it on the roadsides in Napa, and it's just encroaching into the vineyards at Napa Valley College," he said.

Posted on Tuesday, August 13, 2013 at 12:03 PM

Invasive weed threatens California rice

Winged primrose willow grows erect, unlike other waterprimroses, which grow prostrate on the ground.
Winged primrose willow, a weed native to South America, was found last fall in a few Butte County rice fields, alarming agriculture officials about its possible spread to Colusa and Glenn counties, said an article in the Colusa County Sun-Herald.

The weed is highly invasive, produces vast quantities of seeds and survives under a wide range of hydrological and climatic conditions.

"Farmers have to keep an eye out for this weed, and let us know if they think they have it," said Luis Espino, UC Cooperative Extension advisor in Colusa, Glenn and Yolo counties, a rice production expert.

Unlike other waterprimroses, the winged primrose willow can grow within flooded rice fields, which makes it even more problematic for local farmers if it should get established in this area, Espino said.


Posted on Friday, April 27, 2012 at 10:25 AM

UC farm advisor outlines problems posed by invasive species

Faber said kudzu (shown above) was introduced as a ground cover, and then took off in the southern U.S.
Invasive plants and insects are proliferating faster than ever, causing massive problems in the environment, UC Cooperative Extension farm advisor Ben Faber told farmers at the Ventura County Research Symposium yesterday, the Ventura County Star reported.

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.

Posted on Thursday, November 17, 2011 at 8:55 AM
Tags: Ben Faber (1), invasive weeds (3), water (1)
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