Plant Diseases

Small pink and translucent mite with eight legs, four stretched to the front and four stretched back, on a pale orange surface.
Event

Webinar: Citrus Leprosis Threat, Mites, and Mite Management

Aug 26 2025

Presenters: Dr. Sandipa Gautam, Cooperative Extension Area Citrus IPM Advisor, UC Agriculture and Natural Resources; Dr. Kris Godfrey, Project Scientist, Contained Research Facility, UC Davis; Dr. Daniel Carrillo, Assistant Professor, Entomology & Nematology Department, University of Florida; Tera Pitman…
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Green alfalfa field with scattered blooms of purple flowers blowing in the wind.
Event

Webinar: Pest Management in Alfalfa, Small Grains, and Garbanzo Beans

Sep 24 2025

This webinar is part of the UC Ag Experts Talk series. Dr. Michelle Leinfelder-Miles, Delta Crops Resource Management Advisor with the University of California Cooperative Extension, San Joaquin County, will discuss the principles of Integrated Pest Management and pest management in alfalfa, small grains,…
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Tomato leaves with signs of Tobacco Mosaic Virus. Jack Kelly Clark, UC IPM Program
Article

A Virus in the Garden

June 24, 2025
Most gardeners are aware of plant diseases that can wreak havoc in their gardens. If you grow fruit trees, you may be confronted with curled, reddened peach leaves (peach leaf curl fungus). If you grow apples or pears, your trees may sometimes look like they were scorched with a blow torch (fire blight…
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Threecornered alfalfa hopper degree day model

The threecornered alfalfa hopper (TCAH) is a vector of Grapevine red blotch virus that causes Grapevine red blotch disease in vineyards. A degree day model was developed to predict the ideal time frame for ground cover management to help reduce TCAH populations in vineyards.
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A brown, dying shrub in front of a row of healthy green shrubs.
Article

Wilted plants: lack of water or disease?

February 4, 2025
By Belinda Messenger-Sikes
A well-watered plant that suddenly wilts or unexpectedly drops its leaves could be infected with the soil pathogen Phytophthora. The disease it causes, Phytophthora root and crown rot, can affect many plants, including ornamental trees and shrubs, fruit trees, and vegetables.
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A cluster of leaves on a branch. Some are flat and green and others are bumpy and red.
Article

When Should You Treat for Peach Leaf Curl?

November 25, 2024
By Lauren Fordyce
While you may not notice symptoms of peach leaf curl until the spring, you should manage it in the fall and winter. Peach leaf curl is a fungal disease that primarily affects peach and nectarine trees.
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Leaves with round holes in them and green fruit with red spots on them.
Article

Wet Weather Tree Diseases

March 26, 2024
By Belinda Messenger-Sikes
After years of drought, we welcome rain in California. But we also recognize that rain can help spread a number of plant diseases. Rain and wind can splash bacteria and fungi from infected leaves, branches, and blossoms to uninfected parts of the tree.
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Several leaves on a branch are distorted and turning red while the others are green and healthy.
Article

Peach Leaf Curl Control Period

March 13, 2024
By Lauren Fordyce
Spring is just around the corner and many types of fruit trees are starting to develop their leaves. If you are growing peaches or nectarines and are now seeing symptoms of peach leaf curl on new leaves, unfortunately it's too late to manage the disease.
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Two leafy green seedlings drooped over onto the soil.
Article

Damping-off of Seedlings

January 24, 2024
By Lauren Fordyce
Springtime planting is almost here but don't rush to plant seeds until the soil has warmed up! Planting seeds too soon, when the soil is cold and wet, risks losing them to damping-off, a disease caused by fungi and oomycetes in the soil.
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