Pests & Diseases

Updated May 29, 2026 at 4:30pmAn invasive insect called the glassy-winged sharpshooter (GWSS) has been found on grapevine shipments sold at select Costco locations in Northern California between April 21 and May 21, 2026. Note that the timeframe for grapevine plants sold at Costco has been extended to April…

Fact Sheet • June 2026 • Download PDF (2.8 MB)What is IPM?Integrated pest management, or IPM, is a way of using multiple methods to manage pests instead of depending on one or two solutions. These methods can include choosing the right planting practices, encouraging beneficial insects, and using sprays only…

Looking to keep your brain stimulated this summer? Need information about garden pests? Join us every third Thursday of the month from 12:00 to 1:00pm PST to learn about a wide range of urban pest management topics. This series is free and open to the public, but advance registration is …

Every year, Emerald Ash Borer Awareness Week reminds us that one small insect can have a massive impact on our communities. The emerald ash borer (EAB) is an invasive metallic green beetle that has caused the death of millions of ash trees across North America, killing nearly 100% of unprotected street trees…

The fourth annual Farm Robotics Challenge will announce its winners during a live awards ceremony on May 21. The event will be livestreamed on YouTube.

A warm March followed by rain in April and May in many parts of California has set up the perfect conditions for the development of an unsightly and damaging tree disease called fire blight. Pome fruit trees like pear and apple, and other related trees like pyracantha, are all susceptible to this bacterial…

In Part 1 of this story, we covered some basics of biological control. Now let’s talk about some of the good bugs helping to control invasive pests in California. Controlling yellow starthistle one weevil at a time Yellow starthistle (or YST) is a harmful invasive plant that is established and…

Have you seen white powdery-looking patches appearing on the leaves of your roses or sycamore trees? While home gardeners may be familiar with this sign of the plant disease powdery mildew on their veggies, ornamental plants and landscape trees can also be infected. In addition to those powdery spots, the…