Invasive Spotlight: Highway Iceplant

A patch of highway iceplant, Carpobrotus edulis. Photo by Mitch Barrie, Flickr.com.

You've probably seen this invasive plant growing along highways or the coast in California. Highway iceplant, Carpobrotus edulis, was intentionally introduced to prevent soil erosion along highways and coasts but it has since invaded many different ecosystems and outcompetes native plant species. The California Invasive Plant Council (Cal-IPC) rated this plant as an A-1 species, meaning it is one of the “most invasive and damaging species that are widespread in the state.”

What does highway iceplant look like?

The highway iceplant, also known as the hottentot fig, is a succulent with fleshy three-sided stems. It grows as dense ground-covering mats and produces large yellow to light pink flowers in the late spring and early summer.

What can you do about highway iceplant?

For decades iceplant was widely promoted as an ornamental landscape plant. While its popularity has dwindled, it may still be available for sale in some nurseries. Avoid buying and planting iceplant. Instead, choose plants native to California and visit the PlantRight website to find similar-looking alternative plants. If you have iceplant on your property, it can easily be removed by hand pulling. Be sure to get all live shoots as it can regrow from any node left behind.

For more information, visit the UC IPM Pest Notes: Invasive Plants or the Cal-IPC Plant Report on the highway iceplant.

Invasive Spotlight: Asian Citrus Psyllid and Huanglongbing Disease

The Asian Citrus Psyllid (ACP) is a small, aphid-sized insect that poses a serious threat to California's citrus trees. This invasive pest can carry and transmit a fatal bacterial disease called Huanglongbing (HLB) to all citrus species. HLB has already decimated citrus groves throughout Florida, costing the citrus industry millions of dollars. The psyllid is currently present in Southern California, but preventative measures can keep the disease and insect from spreading to California's citrus growing regions.

What does the Asian citrus psyllid look like?

Asian citrus psyllid adults are 1/6 to 1/8 inch long with brown wings and red eyes. They feed on plants at a 45-degree angle, with their heads down and back end in the air, unlike any other citrus pest. Their feeding causes twisted or distorted leaves. Nymphs are wingless, flattened, orange to brownish, and are generally found on young leaves and shoots. Both adults and nymphs feed on plant sap and excrete honeydew, but nymphs produce distinct waxy tubules to help clear the sugary waste from their bodies.

What are the symptoms of Huanglongbing disease?

An early symptom of HLB is irregular yellowing of leaves, on an individual limb or in one sector of a tree's canopy. Yellowed leaves are blotchy or mottled, but not symmetrically yellow like a nutrient deficiency. As the disease progresses, the fruit will become smaller, more bitter, and may not ripen properly. Once trees are infected, it may take up to two years for obvious symptoms to occur and trees can die within 5-10 years.

What can you about the Asian citrus psyllid and Huanglongbing disease?

It is estimated that 6 out of every 10 California residences have at least one citrus tree on the property. Inspecting your own citrus trees is vital to prevent the spread of ACP and HLB. Check your citrus trees for the Asian citrus psyllid, especially in spring and fall when new growth is abundant. If you think you have found ACP or suspect HLB infection, contact the CDFA Exotic Pest Hotline at 1-800-491-1899 or your local county agricultural commissioner.

To learn more about Asian citrus psyllid and Huanglongbing disease, see the UC IPM Pest Notes: Asian Citrus Psyllid and Huanglongbing Disease and view UC IPM's online training.

California Invasive Species Action Week!

The 10^th annual California Invasive Species Action Week (CISAW) will kick off Saturday June 3^rd and runs to Sunday June 11^th. This week is designed to raise awareness and encourage public participation in the ongoing fight against invasive species. These invaders are non-native plants, animals, or pathogens that can negatively impact our waters, native ecosystems, agriculture, health, and economy.  

You can participate during Action Week and all year long by doing the following:

1. Check out UC IPM's previous blog posts on invasive species.
2. Burn firewood where you buy it. Do not move firewood to different counties. Visit the California Firewood Task Force website for more information.
3. Find out if there's a pest quarantine in your area and what you can do to minimize spread from the California Department of Food and Agriculture.
4. Don't plant invasive species and when possible, try to plant California natives. Visit the PlantRight website for more information on plant selection.  
5. Report invasive species to your local County Agricultural Commissioner.Contact information for your location can be found at the California Department of Agriculture County/State Liaison page.

6. View the full schedule of events for Action Week at the California Invasive Species Action Week website.

Help us observe Invasive Species Action Week and the fight against invasive species!

The UC Master Gardeners of San Luis Obispo County covered a lot of territory in 2019. Our 90 volunteers recorded over 5,000 volunteer hours and 1100 continuing education hours.

Here's a snapshot of the 2019 activities and what we have planned for 2020.

More than 1,000 SLO County residents attended our monthly workshops in the garden. We visited a variety of community groups and libraries for an additional 18 presentations, which included a collaboration with the SLO Botanical Garden for a speaker series featuring UC Master Gardeners. MGs also staffed 10 information tables at festivals from San Miguel to Morro Bay to Arroyo Grande.

Thank you to everyone who responded to the follow up surveys. Your feedback tells us a lot about what you're are learning and how you're protecting natural resources.

Water conserving practices

• 75% have improved their drip irrigation systems and are more knowledgeable about selecting low water use plants
• 85% have improved their use of mulch

Improved pest management

• 73% have improved their pest monitoring practices
• 59% are reducing pesticide use
  

Improved personal food supply

• 79% have improved their edible growing practices
• 20% have started donating produce to community programs

Sharing the bounty is important. MGs harvested nearly 1100 lbs of fresh fruits and vegetables from the demonstration garden and delivered it directly to the SLO Food Bank.

Good job SLO County!

Looking Ahead at 2020

Visit our website for the 2020 schedule of monthly workshops - https://ucanr.edu/sites/mgslo/. New topics include Ca natives, invasive plants and seed saving.

Additional events and programming in the works include plant sales beginning in April and presentations on Pollinators in the Garden at 6 libraries throughout the county.

Last but not least, we received a record number of applications for the 2020 Master Gardener training class. A class of 34 will begin in January and wrap up in May. The addition of 34 enthusiastic certified Master Gardeners will help us increase programming and outreach efforts to help more home gardeners improve their practices, protect natural resources and have some fun in the process.

Thank you to everyone who came out to our workshops and events this year.

We'll see you in 2020!