Pests & Diseases

Valley oak tree atop a hill of brown grass.
Event

Webinar: Mediterranean Oak Borer & Other Pests of California Oaks

Apr 10 2025

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 Napa, Lake, Sonoma, and Sacramento Counties and has been detected in neighboring El Dorado, Yolo, and Mendocino…
View Event
Bermuda buttercup infesting a bed of landscaped plants.
Article

Spring is in the Air, and Oxalis is Everywhere

April 10th, 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…
View Article
Argentine Ant vs Tamarixia
Article

Ask the Experts Webinars from UC IPM

April 4th, 2025
By Ben A Faber
What Are the UC Ag Experts Talking About?Event NameDateUC Ag Experts Talk: Considerations for Cover Crops and Weed Management 3/19/2025UC Ag Experts Talk: Integrated Soil Health Management 4/30/2025UC Ag Experts Talk: Mealybug Management in Citrus Orchards in California 5/21/2025What is…
View Article
Armillaria
Documents

Armillaria

 Armillaria root rot, also known as Oak root fungus, is a disease of many different plants.  There is no known effective cure.  Root rot fungus disease of trees and woody plants. Affects palms, succulents, ferns and other herbaceous plants like begonia, daffodil, dahlia, and geranium.  No…
View Documents
Damping Off
Documents

Damping Off

Seedlings sometimes fail to sprout or die soon after. Seeds may rot before germinating, shoots may decay before they emerge, or stems of seedlings may be attacked near the soil line, causing young plants to collapse. These diseases are collectively called “damping off,” likely caused by a number of soil…
View Documents
downy mildew
Documents

Downy Mildew

Downy mildews, including Peronospora and Plasmopara spp., are pathogenic water molds (oomycetes) that primarily damage foliage. Hosts include cane berries, roses, various herbaceous ornamentals, and many fruit, grain, and vegetable crops. CategoryFungiSigns/SymptomsDowny mildew causes pale green to…
View Documents
Brown, scorched-looking leaves are symptoms of fire blight in trees in the apple and pear family. Photo: Sebastian Stabinger
Documents

Fire Blight

 Fire blight is a common and frequently destructive disease of pome fruit trees and related plants.  The disease can destroy limbs and even entire shrubs or trees. Caused by the bacterium Erwinia amylovora. Pear (Pyrus species) and quince (Cydonia) are extremely susceptible.  Apple, crabapple …
View Documents
fusarium wilt
Documents

Fusarium Wilt

Fungus that only infects tomatoes. Like verticillium, causes leaf yellowing and discoloration of water-conducting tissues. Fungi spread in soil water, on equipment, transplants, or tubers. Once inside the root, the fungus grows until it reaches the water-conducting cells, inside which it spreads upward…
View Documents
blight
Documents

Late Blight on Potatoes

Late blight of potato was responsible for the Irish potato famine of the late 1840s. Late blight is caused by the oomycete Phytophthora infestans. Oomycetes are fungus-like organisms also called water molds, but they are not true fungi. CategoryFungiSigns/SymptomsLesions appear as small dark green water…
View Documents
Subscribe to Pests & Diseases