This time of year, you may notice a white, powdery looking growth on fruit, vegetable plants or ornamental plants in your garden. What is it? It could be powdery mildew.

Powdery mildew is caused by several different fungi that may attack plant leaf surfaces, shoots, fruits, and flowers. There are several species of powdery mildew; all are spread by wind and thrive in shady areas when temperatures are between 60-80 °F. The fungi attack both new and old foliage, and can be a problem on certain plants. The disease usually occurs first on new leaves, before spreading to older parts of the plant. This is why over fertilizing worsens powdery mildew. 

Ornamental Plants

Many woody and herbaceous...

Many areas in California have experienced a hot and dusty summer, perfect conditions that favor spider mites! These tiny arachnids are plant pests whose numbers can get very high during the warm months of June through September.

Spider mites damage plants by sucking cell contents from leaves. If you see plant leaves with light dots on them (stippling) that turn yellowish or reddish and drop off, and/or large amounts of fine webbing on leaves, twigs, and fruit, your plants might have spider mites.

Spider mites look like tiny, moving dots that will move around rapidly when disturbed. To correctly identify these pests, use a 10x hands lens to view...

The incurable citrus tree disease huanglongbing, or HLB, has been detected in Los Angeles and Orange counties and most recently in