- Author: Denise Godbout-Avant
What are Mushrooms?
Mushrooms, also known as toadstools, are the visible reproductive body of a fungus which produces spores. Mushrooms seem to magically appear and then quickly disappear. The fruiting body you see releases its spores to be spread by air currents, with the mushroom then drying up. When spores land in a satisfactory location they will germinate, sending out long filaments called hyphae.
The standard visible morphology of a mushroom is a stipe (stem) topped by a cap with gills on the underside, but mushrooms come in a variety of sizes, shapes, colors and uses. The common mushroom is the cultivated white button mushroom we see in stores. Other shapes include puffball, stinkhorn, morel, bolete, shelf, truffles, bird's nests, orange peel, and agarics. Colors vary from white, black, brown, yellow, and occasionally orange and reds. Sizes range from microscopic to 5 feet in diameter!
Many mushrooms also have an underground filament called mycelium (plural: mycelia). You can sometimes see mycelia when turning over a rotting log or by digging underneath a cluster of mushrooms. The mycelia will look like a stringy mat of white fibers in and around plant and tree roots.
History & Uses
The terms “mushroom” and “toadstool” go back centuries. Much of their mystery is due to their association with poisonings and accidental deaths. They were thought to be special and supernatural by many cultures including Egyptians and Romans who associated them with their rulers and gods. Chinese and Japanese cultures have utilized mushrooms for medicinal purposes for thousands of years. Hallucinogenic mushroom species have a history of use among Indigenous people of Mesoamerica for religious purposes and healing from pre-Columbian times. People today correlate hallucinogenic mushrooms with the hippie period in the 1960s. Edible mushroom species have been found in 13,000-year-old archaeological sites in Chile. Truffles have been collected as far back as 1600 BC.
Edible Mushrooms
Poisonous mushrooms can be very hard to identify in the wild, so unless you have been taught how to classify mushrooms by an expert, it is recommended you buy from a reliable grocery store. Mycologists identify mushrooms by observing their morphology, getting spore prints, microscopic study, and with mushroom keys, though applying DNA technology is becoming common.
You can also grow your own mushrooms at home – kits are available online and at some plant nurseries.
Mushrooms in Your Garden and Lawn
- Common mushrooms in gardens include inky caps, stinkhorns, puffballs, or bird's nests.
- A “fairy ring” of mushrooms is an arc of mushrooms around a circle of darker green lawn, often in shady areas. They get their name from an ancient belief that fairies danced in these circles around the mushrooms.
- Mushrooms in lawns often develop from buried scraps such as pieces of wood or dead tree roots.
- A cluster of honey-colored mushrooms may appear at the base of a tree in the fall. These don't usually appear unless the host tree is dying.
- New lawns require frequent irrigation until established, thus creating a perfect setting for mushrooms, which is why they often appear in freshly planted lawns.
Remember, the mushrooms you see are the fruiting bodies that produce spores. Thus, removing them will not kill the underground mycelia from which they are growing, unless you pick them prior to their release of spores. However, you can try to reduce the number of mushrooms you have by decreasing the amount and frequency of watering your lawn and let the grass dry in between. For more information in dealing with mushrooms in your lawn, visit the UC IPM website at http://ipm.ucanr.edu/PMG/PESTNOTES/pn74100.html
Whether you see mushrooms in the forest, in your lawn or neighborhood, I hope you can appreciate and enjoy these unique, complex, beautiful, valuable, diverse, and magical organisms!
-This article was originally published on December 6, 2021.
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.
/h4>/h4>/h4>/h4>- Author: Lauren Fordyce
Plentiful rainfall in California this spring created an ideal environment for many plants to thrive, including wildflowers, trees, and shrubs that desperately needed the water. However, other potentially harmful species also benefited from the unusually wet weather. Of particular concern are poisonous plants which are growing abundantly in parks and wildlands this year. These plants pose health risks to people, especially children, and pets. Being able to identify poisonous plants and understand available control options is critical for the safety of people who encounter them. While several poisonous plants grow in California, a few of the more common are detailed below along with information on how best to remove or manage them.
Poison Hemlock
Poison hemlock (Conium maculatum) is an invasive weed that thrives in disturbed areas but it can also invade native plant communities. It is commonly found in meadows, pastures, and fields, and may spread quickly after the rainy season. All parts of the plant are toxic to humans and animals when ingested. Touching poison hemlock may cause contact dermatitis for some people.
Poison hemlock can easily be mistaken for its relatives in the family Apiaceae, like carrot, parsley, parsnip, or celery, especially when plants are young. Leaves are triangular shaped, deeply lobed, and have opposite branching (Figure 1). Unlike invasive wild carrot (Daucus carota), poison hemlock lacks hairs on its leaves and stems. Poison hemlock has white, umbrella-shaped flowers, similar to those of native cow parsnip (Heracleum maximum). However, cow parsnip has much wider leaves that are arranged in threes and can measure up to 16 inches wide. You can also distinguish poison hemlock from similar plants by checking for purple streaks or spots along its hollow stems. Mature plants can reach almost 10 feet tall.
Poison hemlock is best controlled when young, before it sets seed. It releases seeds over several months, and copious amounts of seed can build up in the soil. Small infestations of poison hemlock can be managed by hand removal while wearing gloves or hoeing the area. The taproot must also be removed to prevent regrowth. Repeatedly mowing poison hemlock can deplete its energy and prevent seed production. Be sure to clean mower blades to avoid moving seeds to new areas. Herbicides containing 2,4-D, triclopyr, or imazapyr work best on seedlings. Glyphosate, chlorsulfuron, and metsulfuron are effective on larger, rapidly growing plants. Repeated herbicide applications may be required for several years until the seedbank has been depleted. Never burn poison hemlock as this can release its toxins into the air.
Poison Oak
Poison oak (Toxicodendron diversilobum) is a deciduous native plant that is widespread through California's coastlands, woodlands, rangelands, riparian areas, and urban parks and gardens. Poison oak, like its eastern relative poison ivy, contains an oil called urushiol that can cause contact dermatitis and itchy, weeping rashes on the skin of people who are sensitive to urushiol. The allergy-causing oils can persist on tools, clothing, and other objects for months or even years.
The old adage “leaves of three, let it be” often holds true for poison oak, but not always. Plants normally consist of 3 leaflets, but may sometimes contain 5, 7, or 9. Leaves are slightly lobed and occur alternately along the stem (Figure 2). They can vary in color and texture from glossy to dull, and thin to leathery. In open, sunny areas poison oak can grow to be a dense shrub. In more shaded areas it grows as a climbing vine. It can easily spread to cover large areas via seeds and rhizomes.
Poison oak can be removed through hand pulling and digging (including roots) with a shovel; wear protective clothing and gloves, and promptly wash or discard them afterwards. Removed plants should be carefully disposed of since the oils remain hazardous even after the plants have dried. Never burn or mow poison oak as it will release its oils into the air, posing an inhalation risk. Herbicides that contain at least 41% glyphosate or 61% triclopyr ester have been shown to provide effective control. Dicamba and imazapyr can also be used. Foliar applications should be made in the late spring or late summer, depending on the chemical used. Cut-stump treatments can be performed in the spring or fall.
Burning and Stinging Nettles
Unlike poison oak and poison hemlock which may only affect some people, burning and stinging nettles (Table 1) cause burning rashes to anyone who touches them. The rashes are caused by a toxin in the prickly hairs on the leaves and stems. Contact with burning and stinging nettles can cause blisters and red patches. Itching, burning, and tingling sensations may persist on the affected skin for several hours.
Burning nettle | Stinging nettle |
Found in disturbed sites, roadsides, orchards, and gardens; common along the coast | Found in unmanaged areas, riverbanks, moist wildlands, and roadsides |
Summer annual; blooms January to April | Perennial; blooms March to September |
Spreads by seed | Spreads by seed and rhizomes |
5 inches to 2 feet tall when mature | 3½ to 10 feet tall when mature |
Opposite leaves with toothed margins; ½ inch to 2 inches long (Figure 3) | Opposite leaves with toothed margins; 2½ to 5 inches long |
Burning and stinging nettles can be nuisance plants as well as health hazards. However, they are not considered invasive or noxious weeds. In fact, stinging nettle is native to California so control should only be performed if plants are causing economic or health concerns. Hand pulling while wearing gloves can be effective, but the underground stems (rhizomes) of stinging nettle must also be removed. Mowing close to the ground can prevent seed development and spread, but if done too early in the season the nettles will regrow rapidly from the rhizomes. The active ingredients 2,4-D, aminopyralid, dicamba, glyphosate, and triclopyr provide excellent control for both stinging and burning nettles.
To learn more about controlling these toxic weeds in landscapes and natural areas, see the Weeds page on the UC IPM website at ipm.ucanr.edu/PMG/menu.weeds.html or the Weed Research Information Center wric.ucdavis.edu. These and other weeds are described in the book Weed Control in Natural Areas in the Western United States, available from the UC ANR catalog anrcatalog.ucanr.edu.
/h2>/h2>/h2>- Author: Saoimanu Sope
Hopland REC turns 2018 River Fire devastation into research opportunity
The destructiveness of wildfire flames is easy to see, but dangers may lurk in the ashes they leave behind. A group of UC Davis scientists studied lambs at the UC Hopland Research and Extension Center, investigating whether pastures regrown after a wildfire cause toxic metal residues in grazing animals. The results, published in California Agriculture journal, showed that grazing on regrown pastures did not significantly alter the metal content of the lambs' meat and wool. That's good news for ranchers and consumers from a food safety perspective.
In 2018, the River Fire burned six miles north of Hopland, scorching two-thirds of the land at Hopland REC, including areas in its sheep station. Since Hopland REC conducts ecological and agricultural research, they had data and some meat samples from the sheep flock that lived on site before the River Fire occurred.
“A bunch of researchers came together to brainstorm how we could take advantage of this unfortunate event,” said Sarah Depenbrock, assistant professor and agronomist in the Medicine and Epidemiology department of UC Davis School of Veterinary Medicine.
Burning has played a role in agricultural processes for many years, but wildfires in California are creating a new fire landscape that interests researchers like Depenbrock. “The problem, now, is that these big wildfires probably interact with agricultural land differently than routine prescribed burns,” she said.
Large, older plants on lands that have not recently burned may contain high concentrations of metals, sequestered over years of growth. Mercury is an example of a potentially dangerous metal that can be sequestered in living things over time. These metals may be distributed in ash after the vegetation burns so the scientists examined lambs that had grazed on Hopland REC's recently burned pastures, during the first plant regrowth.
Uncertain results raise more questions
The researchers compared meat from lambs that grazed on regrown pastures in 2019, after the River Fire, to frozen meat samples that were collected the year before the fire. Lead, mercury, arsenic, molybdenum, cadmium, beryllium, cobalt and nickel were not detected in any animal samples. There were, however, a few (3 out of 26) samples that tested positive for the non-essential (potentially toxic heavy metals) chromium and thallium in the group grazing after the fire.
Due to the small number of samples testing positive, researchers could not determine statistically if this contamination was associated with grazing the burn regrowth. The concentrations of chromium and thallium found may or may not be potentially toxic, depending on the specific forms and how much meat a person consumes.
Another aspect of the study included testing lambs' wool to determine if it is a good method of judging the mineral content of its meat. “In general, we learned that it wasn't well-correlated with most meat metal content of interest, which is worth knowing. However, because we did not identify many of the non-essential metals of particular toxologic concern, such as lead or mercury, in any animal samples we could not determine if testing wool would be useful for those metals, as they are in other species,” said Depenbrock. She also notes that the wool from animals whose meat tested positive for chromium and thallium, did not test positive for these metals in their wool.
As the challenges in managing wildfires persist, so does the risk of contamination of food products stemming from grazing livestock.
“We didn't get striking evidence that tells us, when there's a fire, it means everything is contaminated with heavy metals,” said Depenbrock. “But it does raise the question that maybe we should be doing a little bit of surveillance to see if this is spurious or common. And we should be finding a way to screen grazing herds.”
Recommendations to manage copper concerns
“It's a very small study, but it was quite interesting to find that copper was actually lower in the postfire grazing group, which makes me wonder,” Depenbrock said.
Diseases associated with copper deficiency are a major concern in sheep. For example, congenital swayback can result in stillbirth or an animal's inability to stand on its own due to incurable changes to the spinal cord. Other adverse effects include reduced growth rate, anemia, wool defects and fiber depigmentation, and osteoporosis with higher risk of spontaneous fractures. Copper excess can also cause serious and sometimes fatal disease.
Many of the forage sources, grazing areas and rangelands in California are copper deficient, while some feed sources have excess copper. Screening and monitoring livestock herds for trace minerals including copper is crucial.
To test for copper, she advises livestock owners to obtain mineral concentrations from the organs of euthanized or dead animals. Samples from the liver and kidney are the most valuable organs to identify a potential problem in the herd. UC Davis Veterinary Medicine's California Animal Health and Food Safety (CAHFS) labs do this testing routinely.
Second, monitor and record mineral supplementation and, third, maintain updated health records to make informed decisions regarding supplementation based on a herd or flock's known problems. For example, if a producer is not accustomed to supplementing copper, Depenbrock highly recommends working with a veterinarian to start out (as there are numerous copper supplement products of varying concentration on the market), to determine a testing or screening plan, and review health records for problems potentially associated with copper.
To read the full text of the study, visit https://calag.ucanr.edu/Archive/?article=ca.2022a0016.
/h3>/h3>/h3>- Author: Rachael Freeman Long
- Author: Morgan P. Doran
- Author: Robert Poppenga
- Author: Daniel H. Putnam
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From the Alfalfa & Forage News blog (April 29, 2022)
What is vetch? There are several species that are commonly grown as crops, cover crops or weeds (see list at the bottom). Vetch is a winter-hardy legume that's favored by early fall rains, which we had lots of last October (5.5-in in 24-hr in Sacramento). Vetch is also a nitrogen-fixing plant that works well as a cover crop in farming systems. It's also a good forage for bees and other pollinators and has extra floral nectaries (glands on stems that produce nectar) that attract beneficial insects like parasitoid wasps that prey on pests.
Is it a good livestock feed? Yes and no. As an annual leguminous vigorous herbaceous plant, vetch has high protein and relatively low fiber and reasonably high yields. It's vigorous growth and N fixing qualities is why it is so valuable as a cover crop, but it can also be grazed or fed as hay. Its quality is lower than that of alfalfa or clovers (protein levels from 15-20% depending upon stage of growth). It is commonly grown in mixes with small grains or grasses as a mix in different parts of the US. Vetch hay is difficult to handle due to the vine-like characteristics, and caution should be used due to anti-nutritional compounds and livestock palatability.
Anti-nutritional compounds. However, vetch hay can cause serious (and potentially fatal) animal health problems, so is not recommended as a primary forage for horses and cows. Most of the anti-nutritional compounds are concentrated in the seeds, so immature harvests are recommended. Vetch seeds are poisonous; they contain cyanogenic glycosides and a diglucoside that can cause a neurologic disease. Although hairy vetch (V. villosa) and purple vetch (V. benghalensis) seeds are the most toxic (being very closely related), other vetches have toxic seeds too, including common vetch (V. sativa). In addition, a toxin in vetch foliage is associated with a dermatitis or skin sensitivity disease, though this is extremely rare and not well understood. Most cases of vetch-induced dermatitis involve black cattle, such as Angus or Holstein, and horses can also be affected, so there may be specific susceptibility explained by a genetic predisposition. Lack of good information makes is difficult to assess vetch hay suitability for small ruminants like sheep, though there is anecdotal information that suggests it might be okay for goats.
How about rangelands? Vetch growing on grazing rangelands is actually a good, high-protein feed for livestock. In open range, cattle typically won't graze vetch until it dries down and seeds have shattered. On a hot day you can hear dry pods snap, crackle, and pop, like a bowl of Rice Krispies. Vetch is not favored by livestock when green due to low palatability (bitterness).
How about pastureland? Fenced pastures loaded with vetch going to seed could spell trouble for horses and cows, especially if there is little else to eat. Toxicity risk can be alleviated by ensuring other forage options are available and by stocking animals at very low densities and giving them the option to selectively consume non-toxic plants and avoid toxic plants. Again, once the plant has dried down and seeds have shattered (detached and fallen), it should be okay as grazing feed.
How big a problem is vetch toxicity? The California Animal Health and Food Safety Laboratory at UC Davis has had a few cases of vetch toxicity to cattle and horses over the years, but not many. It's still unclear if this means few cattle are exposed to vetch or few cattle actually develop disease. It's still kind of a mystery as to why vetch is sometimes a problem and other times not. It might be a matter of the degree of its presence in animal diets – low percentage is okay, high percentage more problematic. "Dose makes the poison" as a toxicologist would say.
How about croplands? Oats and vetch used to be a popular mix for feed, but not anymore and hay growers try to keep it out of their forage crops. If cereal grains are in a crop rotation, vetch seed is about the same size as wheat and barley kernels, making it hard and expensive to separate during seed cleaning. Vetch is also hard-seeded, meaning seed can lie in the ground dormant for years and germinate when not wanted, though the viability for most seed is about 5 years, allowing opportunities for management. For control, one can mow prior to pod and seed set or use broadleaf or pre-emergent herbicides if needed.
Vetch identification. To differentiate different species of vetch one needs to look at the flowers. Common vetch (V. sativa) has flowers with a short stalk (peduncle), meaning the flowers are attached close to the stem from where it originates (picture). Hairy vetch (V. villosa), purple vetch (V. benghalensis), and American vetch (V. americana) all have flowers with long stalks. Hairy and purple vetch flowers are aligned on one side of the flower axis (picture) whereas American vetch flowers are more upright (picture). Purple vetch will generally have flowers about the same size as the leaflets (picture), while the flowers on hairy vetch are generally larger or longer than the leaflet (picture).
What types of vetch are found around California on agricultural and rangelands? According to Dr. Alison Colwell, Curator, UC Davis Herbarium, the following are the rankings of vetch (Vicia) species abundance by county. This information comes from the Consortium of California Herbaria (https://cch2.org). The data are from all years that collections were made, which is basically the past 100 years. The take-home point of this analysis is that there are several similar vetch species that are all spottily dominant around California.
Yolo County (all ag)
- V. villosa (hairy; lana/woollypod subsp. varia)
- V. sativa (common)
- V. benghalensis (purple)
Mariposa County (mostly ranch/public land, central)
- V. americana (American vetch; native plant)
- V. sativa
- V. benghalensis
Butte County (part ag, part ranch, north)
- V. villosa
- V. sativa
- V. americana
Tulare County (ag, arid, south)
- V. americana
- (3-way tie) V. benghalensis, V. sativa and V. villosa
Stanislaus County (ag, central)
- V. villosa
- V. sativa
- V. americana
Original source: Alfalfa & Forage Newsblog (April 29, 2022)
- Author: Travis Bean
Invasive plants don't get much coverage in the news, especially at the state and national level. As I've argued previously, this lack of media attention is a problem when it comes to motivating the public and political players into proactively funding invasive plant management and mitigating impacts to human health, infrastructure, and natural resources. Admittedly, as a weed scientist, I'm biased on the issue.
However, sometimes there is a particular plant that is just so terrifying that it lends itself to coverage in a major news outlet, as was the case for this article about giant hogweed (Heracleum mantegazzianum) by Caitlin O'Kane on CBS news last month: "Giant hogweed, plant that causes blindness and third-degree burns, discovered in Virginia." As the headline suggests, this is a plant you should keep a safe distance from if you are unlucky enough to come across it. Just in case you're thinking that this is just sensationalism, there's a page on Snopes that confirms the assertions about giant hogweed's dangerous sap (and also confirms its place in popular culture). I won't provide a direct link here, but a simple Google search of "giant hogweed" turns up some images of what look like very painful giant hogweed injuries. The photograph below was taken by Gavin Edmondstone:
Giant hogweed is native to the Caucasus region and southwest Asia, and is presently found in Europe, Canada, the United States, Australia, and New Zealand, where it was likely introduced as an ornamental for its showy inflorescence. Apparently it was a well known nuisance in Britain, so much so that the band Genesis released the ominous song "Return of the Giant Hogweed" on their 1971 album Nursery Cryme:
"Turn and run
Nothing can stop them
Around every river and canal their power is growing..." (Google the song title for the complete lyrics- they are fantastic! And strangely factual...)
Here in the US, giant hogweed is mostly found in New England and the Pacific Northwest. As the article suggests, giant hogweed has expanded down the east coast and was recently discovered for the first time in Virginia. Over on the west coast, it has made it as far south as northwestern Oregon. Californians should be on the lookout however, as we do share some similar habitats with Oregon, particularly in the northern part of the state. California also has a native congener called "cowparsnip" (Heracleum maximum), suggesting that suitable habitats do exist across the state.
For those involved with management of this plant, a great resource with information on controlling giant hogweed can be found in DiTomaso et al. (2013) Weed Control in Natural Areas in the Western United States, as well as several state conservation webpages. Before embarking on control, be careful not to confuse with natives that may look similar- your local county Natural Resources Advisor can be of great help in correctly identifying invasive plants. And it should go without saying, but given the potential for painful injury, this is a plant you may want to enlist the help of professionals with if you have it on your property.
As the band Genesis proclaims:
We must destroy them
They infiltrate each city with their thick dark warning odor
They seem immune to all our herbicidal battering"
Now if we could just get some similar coverage in the press or popular culture for our less glamorous but equally terrifying invasive grasses...