Invasive Species

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Cross section of a tree trunk that has trellis-like tunnels throughout. The tunnels are dark stained and go deep into the wood.
Pests in the Urban Landscape: Article

Mediterranean Oak Borer: Questions & Answers

May 28, 2025
By Lauren Fordyce
The Mediterranean Oak Borer (MOB) is an invasive ambrosia beetle that infests several species of white oaks in California: valley oak, blue oak, and Oregon oak. The beetle is spreading rapidly in Northern California counties and there is considerable potential for the beetle's range to expand as they…
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An adult emerald ash borer beetle on a leaf damaged by its feeding.
Pests in the Urban Landscape: Article

Emerald Ash Borer Awareness Week 2025

May 15, 2025
By Lindsey Hack
Tiny but destructive, the emerald ash borer (EAB) is an invasive beetle that has killed millions of ash trees across North America. In some cases, infested regions have lost nearly 100% of their ash trees to this pest. Though EAB has not yet been found in California, it was detected on the West Coast for the…
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Tree-of-heaven growing over a sidewealk in a neighborhood.
Pests in the Urban Landscape: Article

Invasive Pest Spotlight: Tree-of-Heaven

May 7, 2025
By Cherie Shook
Tree-of-heaven, Ailanthus altissima, was originally from China and became a popular landscape shade tree in the 1800’s. However, its rapid growth, aggressive spread, and native habitat disruption have made it a global problem. Reproducing rapidly through dense root suckers and wind dispersal of its “winged”…
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A smiling UC Master Gardener volunteer in an orange hat and green apron stands with arms raised in a garden setting, surrounded by people and plants.
UC Master Gardener Program Statewide Blog: Article

Top 5 Ways Gardeners Can Help Stop Invasive Species

April 25, 2025
By Lauren L Snowden
Did you know that your backyard, balcony, or community plot is more than just a space for flowers and veggies? It's also a frontline defense against invasive species! As gardeners, we’re uniquely positioned to protect local ecosystems, and the good news is—it doesn’t take a lot to make a big difference.Here…
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Bermuda buttercup infesting a bed of landscaped plants.
Pests in the Urban Landscape: Article

Spring is in the Air, and Oxalis is Everywhere

April 17, 2025
By Lindsey Hack
Bermuda buttercup (Oxalis pes-caprae), also called buttercup oxalis or sourgrass, might be a familiar sight in winter and spring, particularly to those who live in coastal regions or the Sacramento Valley. Some people enjoy seeing this plant’s cheerful yellow flowers pop up in their spring gardens, but for…
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Detector dog stands on a small box, gazing at handler to alert a find
UC Master Gardener Program Statewide Blog: Article

Dogs Sniff Out Pest Problems

March 27, 2025
By Lindsey Hack
Dogs use their keen sense of smell to help humans every day. Their powerful noses alert us to danger, aid in search and rescue operations, and even have the potential to diagnose diseases. But did you know that some dogs have been trained to sniff out harmful invasive pests? Enter the detector dogs! …
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Valley oak tree atop a hill of brown grass.
Pests in the Urban Landscape: Article

Webinar: Mediterranean Oak Borer and Other Oak Pests

March 26, 2025
By Lauren Fordyce
Join UC IPM for a free webinar on the invasive Mediterranean Oak Borer (MOB) and other important oak tree pests on April 10, 2025 from 6:00pm to 7:30pm. The Mediterranean Oak Borer (MOB) is an invasive ambrosia beetle that infests several species of white oaks in California: valley oak, blue oak,…
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Banner weeds
UC Marin Master Gardeners: Page

Weeds & Invasive Plants

Lambert Yuri, Unsplash > Types of weeds > Life cycle of weeds > How to identify weeds > Managing weeds > What to do when you already have weeds > What you should know about weedkillers > How to prevent weeds Weeds are generally defined as any plant growing in a place where you dont want it, or a pla...
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Asian Citrus Psyllid Michael E. Rogers University of Florida
UC Master Gardeners of Santa Clara County: Page

Invasive Pests and Quarantines

Current Quarantines: A Mediterranean Fruit Fly quarantine is in effect for large parts of San Jose, as well as sections of Campbell, Los Gatos, Santa Clara, and Milpitas. Asian citrus psyllid (ACP) County-wide quarantine on citrus fruits, leaves, and trees; also Indian curry leaf and other hosts The Asian…
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