Posts Tagged: invasive weeds
Scotch broom (Cytisus scoparius) and Portuguese broom (Cytisus striatus). Brooms were introduced as ornamentals, but also were used extensively for erosion control along roadsides and in mined areas.
Now growing profusely in California forests, on roadsides, and wildlands, brooms:
- Crowd out out desirable vegetation
- Form impenetrable thickets that limit access to some areas
- Shade out tree seedlings, and make reforestation difficult
- Burn readily, increasing the intensity of fire, and carry fire to the tree canopy
- Are toxic to cattle and horses and unpalatable to most wildlife
- Produce abundant, long-lived seed
- Are able to fix atmospheric nitrogen, giving broom a competitive advantage over native plants
Management of these and other weeds are presented in the recently published second edition of Forest and Right-of-Way Pest Control. Invasive species that create a dangerous wildfire hazard and crowd out desirable vegetation and wildlife are examples of why this book emphasizes vegetation management and pesticide handling, including correct equipment calibration and effective herbicide application. The second edition also provides broader coverage of insects, plant pathogens, vertebrate pests, and the various practices to manage them, recognizing that lands commonly have multiple uses and when and how pests are managed depends on many considerations with sometimes conflicting goals.
Experts with Cal-Fire, Caltrans, PG&E, USDA Forest Service, private industry, the University of California (UC) Berkeley and Davis campuses, UC County Cooperative Extension offices, and the California Department of Pesticide Regulation (DPR) contributed to Forest and Right-of-Way Pest Control, prepared by UC ANR's Statewide Integrated Pest Management Program.
Forest and Right-of-Way Pest Control is available for $35 online in the UC ANR Catalog. The table of contents and more information about the book are available on the UC IPM website. You can also preview and electronically search the contents on Google Books.
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.
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.
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.