Pests & Diseases

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…

Reflections on thrips and INSV during the 2025 Lettuce Season Dylan J. Beal, Daniel K. Hasegawa, Yu-Chen Wang INSV: Early Spring and Summer: isolated, small INSV outbreaks were observed. These outbreaks were associated with adjacent, unmanaged weedy sites.Late Summer and early Fall: more…

If you missed our first Urban & Community IPM webinar of the year, Pests of Backyard Chickens, don’t fret, we have more for you! Join us every third Thursday of the month from 12:00pm to 1:00pm PT to learn about a wide range of urban pest management topics. This series is free and open to the…

Winter rains and damp conditions in many parts of California may have brought a surprise visitor to your lawn: mushrooms! A few mushrooms sprouting in your lawn can be a good sign: it means there's plenty of organic matter in the soil. But if patches of mushrooms are sprinkled across your lawn, something…

Forget Spotify Wrapped – can you guess which pests received the most hits on UC IPM’s Pests Notes page this year? Here are the top ten pests that made your year: (1) Carpet Beetles  For several years, carpet beetles have been in the top 5 on our playlist. Immature carpet beetles feed on…

From the UC IPM Urban and Community team, we’d like to wish you a happy holiday season! As we reflect on this past year, we’d like to express our gratitude to all of you for joining us to learn about pest management around the home and garden.  This year, we’ve connected with you in various ways:…