- Author: Brent McGhie
By Brent McGhie, UC Master Gardener of Butte County, May 31, 2019
The University of California recommends the use of Integrated Pest Management (IPM) to control garden pests. The goal of IPM is to use the least harmful control method(s) that will be effective in managing a particular pest. Depending on the pest, these methods include one or more of the following: cultural controls, biological controls, mechanical and physical controls and chemical controls (pesticides). When using IPM, it is recommended that gardeners resort to the use of pesticides only as a last resort, after other control methods have been tried and found wanting.
Once the decision to use a pesticide has been made, the next step is to choose the right pesticide. The University of California Pest Notes series is a good source of information for identifying the least toxic pesticides appropriate for a specific pest. Low toxicity pesticides include insecticidal oils and soaps as well as the microbial insecticide, Bacillus thuringiensis, which is effective against many caterpillars, but nontoxic to other animal life. Pest Notes are available from your local UC Master Gardener program (based at the UC Cooperative Extension Office) and online at the UC Statewide IPM Program website.
Whenever a pesticide is used, all instructions should be read and carefully followed. Especially critical are instructions concerning proper application and safety precautions (for example, the use of protective clothing and eyewear).
The only legal way to dispose of pesticides is to take them to a local hazardous waste disposal facility. Do not pour unused or excess material down the drain, onto the soil, into waterways, into gutters, or into the trash. However, in California it is legal for homeowners to dispose of empty pesticide containers in the trash. Before disposing, containers should be triple rinsed and the rinse water used as part of the last application. To find the location of the closest hazardous waste disposal site, call the California Environmental Hotline (1-800-253-2687), or visit the “Earth911” website.
Information in this article is based on “Pesticides: Safe and Effective Use in the Home and Landscape” from the UC IPM website (Pest Note #74126).
For more information on gardening in our area, visit the UC Master Gardener of Butte County webpage at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-7201 or email firstname.lastname@example.org.
- Author: Laura Lukes
By Laura Lukes, UC Master Gardener of Butte County, May 17, 2019
A beautiful tree sits on the north side of Little Chico Creek, shading the picnic table at site #34 in Lower Bidwell Park. Its thick, smooth lower branches are perfect for climbing, and its form is both rounder and more symmetrical than its relatives at higher elevations. And its occurrence at our low altitude (elevation 197 feet) is rare.
Captain George Vancouver of the British Royal Navy commanded a voyage of exploration and diplomacy from 1791 to 1795 which circumnavigated the globe and made contact with five continents. Madrone's species name honors the Scottish surgeon, botanist and naturalist, Archibald Menzies, who noted this tree during Vancouver's voyage of exploration. Menzies, who spent many years at sea serving with the Royal Navy and on private merchant ships, recognized its similarity to the European arbutus, A. unedo, which today is a popular landscape tree in Chico. Its red fruits are shaped like strawberries, and in fact the Spanish word madroño translates as “strawberry tree.” Other common names include madroa, madroo, madroña, and bearberry.
The madrone has evolved an effective method of seed regeneration: each berry contains between three and 30 seeds, and when the berries dry they develop hooked barbs that can latch onto the fur and skin of passing mammals, hitching a ride to colonize new locations.
The Pacific madrone ranges in height from about 33 to 82 feet but can reach up to 100 feet or more in ideal conditions. In those perfect conditions, it can reach a thickness of 5 to 8 feet at the trunk, much like an oak tree. Ideal conditions include a sunny site such as a south or west facing slope with soil that is well drained and lime free.
The largest known specimen of Pacific madrone lived in Joshua Creek Canyon Ecological Reserve on the Big Sur Coast. At least 125 feet tall and more than 25 feet in circumference, and listed on the American Forests National Big Tree list, it sadly was severely burned in the 2016 Soberanes Fire.
A massive, wide-spreading root system increases its ability to withstand summer drought. In fact, the tree prefers dry, well-draining soils and does not tolerate direct watering during the summer months. Once established, Pacific madrone is windfirm, drought enduring, and somewhat tolerant of wet, freezing conditions.
Pacific madrone is a particularly beautiful tree, with its reddish curved trunks supporting a broad, spreading crown of deep green leaves. It is most often seen as a single specimen tree displaying its finery among the more common Douglas fir and tanoak. It is currently declining throughout most of its range, unfortunately due to 100 years of forest fire control and urban development in its native habitat. We are lucky to have our lovely, rare specimen in Lower Bidwell Park.
For more information on gardening in our area, visit the UC Butte County Master Gardener webpage at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-720l or email http://email@example.com.
- Author: Jeanette Alosi
By Jeanette Alosi, UC Master Gardener of Butte County, May 3, 2019
Butte County is known for its delicious citrus. Mandarins are grown commercially in our “banana belt” foothills, and residents in the valley can enjoy citrus grown in their own gardens. However, a tiny flying insect the size of an aphid poses a grave threat to our local citrus. This insect is the Asian citrus psyllid (ACP), a vector for a dangerous and fatal bacterium (Candidatus Liberibacter asiaticus) that causes Huanglongbing (HLB) disease, previously known as Citrus Greening disease. HLB has devastated the Florida citrus industry and has been found in Southern California. Recently the Asian citrus psyllid itself (but not HLB) was found in Sacramento, just 100 miles south.
ACP was first detected in Southern California in 2008, followed by HLB detection in 2012. The psyllid has expanded into the Central Valley, the Central Coast and as far north as the Bay Area and Sacramento. So far there has been no detection of HLB disease outside of Southern California.
There is no cure for HLB, which can kill a tree in 5 to 8 years. Because HLB can only be spread via the ACP, the key to prevent HLB is monitoring for, and controlling, the psyllid.
Adults only live for a few months but can lay several hundred tiny, yellow-orange, almond-shaped eggs in fresh new citrus growth. The tiny wingless nymphs hatch from the eggs and are yellow, orange or brown. They molt 4 times, increasing in size each time.
ACP nymphs only feed on new citrus shoots and leaves. As they feed, a toxin is injected causing leaves to twist and curl, sometimes killing new shoots. Nymphs also produce excess sap or honeydew which promotes the growth of sooty mold. To direct the honeydew away from their bodies, they produce waxy, white tubules. The tubules are unique to the nymphs and are easily identified. Other insects such as aphids can cause these same symptoms, but they do not produce tubules nor are they a vector for the bacterium causing HLB.
Now that the ACP is firmly established in California, the Department of Food and Agriculture (CDFA) is tracking its distribution through the use of yellow sticky traps in commercial and residential areas. ACP quarantine zones are being used to restrict the transport of citrus trees and the spread of the psyllid. Biological controls using predators and parasites that feed on the ACP are being used to help control (but not eradicate) the ACP.
The University of California Division of Agricultural and Natural Resources has an updated map on the spread of the ACP and HLB you can find at https://tinyurl.com/y4lchxk7. A California regulation and quarantine boundary map can be found at http://tinyurl.com/y3ftxzzu.
How you can help. Monitoring citrus for the presence of the ACP and symptoms of HLB is key for controlling this fatal disease. Inspect your citrus any time there is a flush of newly developing leaves; especially in springtime (now), and later on the fall flush. Like aphids, psyllids feed on new, developing leaves. Look for evidence of the ACP in new growth by checking for:
- Adult psyllids feeding, head down and rear end in the air (a 45 degree angle)
- Twisted or notched leaves in new growth
- Sticky honeydew and black sooty mold
- Nymphs that produce waxy, white tubules
- Tiny, yellow, almond-shaped eggs
Control ants that like to “farm” the psyllid honeydew to feed their young. Ants will protect the psyllids from their natural enemies such as parasites and other predators. Only purchase citrus trees from reputable sources and DO NOT transport citrus trees, fruit, or cuttings from areas known to harbor the psyllid.
If you suspect the presence of the ACP or any evidence of HLB disease, immediately contact the Butte County Agricultural Commissioner's Office (530-538-7381), or the CDFA Citrus Threat hotline (800-491-1899).
Sources for more information include:
The UC IPM Publication for ACP and HLB Disease at http://tinyurl.com/yy6jtgy9
California Department of Food and Agriculture at https://www.cdfa.ca.gov/plant/acp/
Citrus Pest & Disease Prevention Program at http://californiacitrusthreat.org/
For more information on gardening in our area, visit the Butte County Master Gardener web page at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-720l or email http://firstname.lastname@example.org.
All photos are from the University of California Division of Agriculture and Natural Resources (ANR).
By Kim Schwind, UC Master Gardener of Butte County, April 5, 2019
In recent months there has been disturbing news about the decline of the Western Monarch population. The North American Monarch Butterfly (Danaus plexippus) is a familiar and charismatic insect. It is known for its amazing migration and its reliance on one plant in particular: milkweed.
There are many hazards along the way. The monarchs that start their migration in the spring will not live long, so in order to lay their eggs they must locate a stand of milkweed. Once laid, it takes three to five days for the eggs to hatch into caterpillars. Monarch caterpillars feed exclusively on milkweed. They grow and molt through five developmental stages over a span of 14 to 18 days. Each caterpillar then spins silk attaching itself to a milkweed leaf or stem and forms a chrysalis (hardened outer protector). After about 10 days it emerges from the chrysalis as an adult butterfly. The lifespan of this adult butterfly is very short – just two to six weeks. In that time it feeds on nectar and continues the migration journey. It might take three or four generations to reach the end of the migration. The last generation (which has a lifespan of months rather than weeks) flies back to its ancestral start where it overwinters in large trees. In Pacific Grove, California they overwinter in a large grove of eucalyptus trees.
The reasons for Monarch decline are varied, and include habitat loss, disease and predation, use of herbicides and pesticides, and climate change.
What can be done to help these beautiful pollinators?
Backyard gardeners can help restore breeding and migratory habitat here in
Milkweed is a perennial plant. It is named for its milky, latex sap. Milkweed is drought tolerant and deer resistant. The native species are not invasive. Milkweed plants develop large fleshy seed pods. When the seeds are mature, the pods pop open, freeing the seeds. Attached to the seeds are fine tufts of hairs (called pappus) which aid dispersal of the seeds: as the wind blows, it catches the silky hairs, carrying the seeds away from the plant. The seeds can be collected from the pods for later propagation or left alone to re-seed themselves.
Home gardeners can aid the Monarch population by adding milkweed to their landscape, pollinator garden, herb garden, or even a patio container. If you own a larger plot of land you might consider letting some of it remain wild, so that the wild nectar producing flowers are available not only for butterflies, but for other pollinators as well. Hedgerows that include milkweed and nectar flowers are a wonderful way of attracting wildlife and pollinators. Creating a monarch way station (a garden that includes milkweed, nectar flowers and a water source) is a nice addition to a community or school garden.
Milkweed is also a great host plant for many other beneficial insects including bees, beetles, and lady beetles (ladybugs). It will also attract a yellow aphid known as Oleander aphid. This aphid will not destroy the plant and it will not infest nearby roses or vegetable gardens. It is plant specific: think of the Oleander aphid as food for the lady beetles.
Avoid using pesticides or herbicides that might damage these breeding and feeding areas. Use caution where you plant the seeds, as milkweed can be toxic to livestock.
Area specific milkweed seeds can be purchased online. You can also find milkweed plants at our upcoming Master Gardener plant sale on Saturday, April 20th, from 10 a.m. to 2 p.m. at our Demonstration Garden at Patrick Ranch, located at 10381 Midway, Durham. For more information on the plant sale, see the Butte County Master Gardener website at https://ucanr.edu/sites/bcmg/
For more information on Monarchs and milkweed, visit the Xerces Society for Invertebrate Conservation. Their website also includes area-specific nectar plant lists.
Finally, local butterfly experts highly recommend Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution by Anurag Agrawal (2017).An interview with Agrawal on this subject recently aired locally on the North State Public Radio program Cultivating Place, and is available as a podcast here.
For more information on gardening in our area, visit our website Butte County Master Gardener. If you have a gardening question or problem, call our Hotline at (530) 538-7201 or email us at email@example.com.
Finding an Ecological Niche: A Three-Part Series on Selected Foothill Woodland and Chaparral Species, Part 3 of 3: The Buckeye
By Laura Lukes, UC Master Gardener of Butte County, March 22, 2019
[Note: Buckeye (Aesculus californica), gray pine (Pinus sabiniana), and blue oak (Quercus douglasii) are tree species that thrive in rugged local foothill woodland and chaparral habitat. In the last two editions, we covered the blue oak and the gray pine. This final installment explores the buckeye. All three species rely on adaptive strategies evolved over time allowing them to thrive in their challenging environment.]
Aesculus californica is a woody shrub or small tree that has adapted to a variety of microclimates in our state: it can be found along the central coast and in the foothill and lower montane elevations of the Sierra Nevada and Cascade Ranges. It grows as far north as the foothills of the Siskiyou Mountains, and as far south as northern Los Angeles County. Native buckeyes can grow in elevations as high as 4,000 feet (one source claims 5,500 feet), but most commonly these plants colonize the foothill altitudes. A true California native, it is found nowhere else in the world.
The California buckeye's variable height attests to its nuanced response to climatic conditions: in northern reaches, the buckeye is shrubby and squat (about 12 feet tall). Further south, it can reach tree-like statures of up to 30 feet. In the kinder habitat conditions of the Coast Range, an Aesculus californica has attained sufficient proportions to be registered as a California Big Tree. That one, in Swanton Pacific Ranch, measures 46 feet high, has a trunk circumference of 176 inches, and a crown that spreads to 60 feet.
The seeds of Aesculus californica are contained in a thick leathery husk, which splits when dried, and are the largest of any non-tropical plant species. These seeds (also called nuts) are the origin of both of its common names: buckeye and horse chestnut. According to Cal Poly's Select Tree web page, Native Americans called the seed "hetuck" (buck eye) because its markings resemble the eye of a deer. The seeds also resemble those of the European sweet chestnut (Castanea sativa). And there the resemblance ends, as the heavy seeds of the California buckeye are toxic, thus limiting its reproductive dispersal strategies to rolling downhill or being conveyed by water.
In addition to toxic seeds, the buckeye's leaves, shoots, and flowers are poisonous. All contain the neurotoxin glycoside aesculin, which is destructive to red blood cells. Although ruminants can feed on very young shoots without harm, and squirrels are able to tolerate the nuts, this toxin protects the buckeye from damage or death by grazing animals. As Ridgeway points out, “the sweetly fragrant flowers of this tree provide a rich pollen and nectar source for native bees, hummingbirds, and many species of butterflies” and are toxic only to non-native honey bees. Honey bees that do survive after ingesting buckeye toxins reproduce “buckeyed-bees” that hatch with deformed, crippled wings or malformed legs and bodies.
A deep taproot allows the buckeye to find water in even the driest of years. A fully developed root system also helps mature California buckeyes to survive drought by enabling the plant to both save and draw on food and water reserves. According to USDA research, California buckeyes recover rapidly following a fire, sending out new shoots during the first growing season, and growing rapidly in following seasons. Some buckeyes can exceed their pre-fire biomass within a few years. They can sprout from their root crown after top-kill by fire within a few weeks, even in the summer months. The USDA also notes that buckeye seeds will probably not survive fire because they are highly susceptible to desiccation by heat.
The same toxin that limited the buckeye seed to a food source only in times of hunger was used to snare a more delicious high protein food source. Native California tribes, including the Pomo, Yokut, and Luiseño, cleverly used the ground-up powder of buckeye seeds to stupefy schools of fish in small streams, making them easier to catch. And the smooth, straight branches of the buckeye made it useful to native peoples as a bow drill and a fire drill.
Our native buckeye is a California beauty and a hardy survivor in some of the least hospitable habitats. In the biological contest for survival, this tough, gorgeous plant holds a winning hand.
For more information on gardening in our area, visit the Butte County Master Gardener web page at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-720l.
Sue Ridgeway, The Bisexual California Buckeye – sinner or survivalist? UCANR website: http://sonomamg.ucanr.edu/Plant_of_the_Month/Aesculus_californica_-_California_buckeye/
M. Kat Anderson, Tending the Wild: Native American Knowledge and the Management of California's Natural Resources (University of California Press, 2005).
Urban Forests Ecosystem Institute at CalPoly SelecTree: https://selectree.calpoly.edu/tree-detail/Aesculus-californica
Stanford Trees: https://trees.stanford.edu/ENCYC/AEScal.htm
USDA: FEIS: FIRE EFFECTS INFORMATION SYSTEM: https://www.fs.fed.us/database/feis/plants/tree/aescal/all.html#FIRE%20ECOLOGY
Carol Bornstein, David Fross, and Bart O'Brien, California Native Plants for the Garden (Cachuma Press, 2005)
Buckeye's namesake is its large nut: By John Morgan from Walnut Creek, CA, USA - IMG_8269, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=25021982
Buckeye flower spike: By Eugene Zelenko - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=2103608
Buckeye leafs out early in the spring: By Eugene Zelenko - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=18732498