Plant Diseases

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Three leaves with large, yellow-orange blotches that turn reddish-brown in their center
UC Ag Experts Talk Webinar Series: Event

UC Ag Experts Talk: Epidemiology and Control of the Invasive Red Leaf Blotch Disease of Almond

Event Date
Feb 18, 2026

This webinar is part of the UC Ag Experts Talk series. Dr. Florent Trouillas, Associate Cooperative Extension Specialist with the Department of Plant Pathology at UC Davis and the Kearney Agricultural Research and Extension Center, will go over the main symptoms of red leaf blotch disease in almond including…
UC Ag Experts Talk Webinar Series
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Irregular red or reddish-purple blotches on grape leaves, starting at the base of the shoots and progressing upward.
UC Ag Experts Talk Webinar Series: Event

Webinar: In-house Diagnostics for Disease Management: LAMP for Red Blotch Detection in Grapevines

Event Date
Nov 12, 2025

This webinar is part of the UC Ag Experts Talk series. Dr. Monica Cooper, Viticulture Farm Advisor with the University of California Cooperative Extension, Napa County, will give an introduction to grapevine red blotch virus (GRBV) including its ecology, physiological impacts, symptoms, and management. She…
UC Ag Experts Talk Webinar Series
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Small pink and translucent mite with eight legs, four stretched to the front and four stretched back, on a pale orange surface.
UC Ag Experts Talk Webinar Series: Event

Webinar: Citrus Leprosis Threat, Mites, and Mite Management

Event Date
Aug 27, 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…
UC Ag Experts Talk Webinar Series
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Green alfalfa field with scattered blooms of purple flowers blowing in the wind.
UC Ag Experts Talk Webinar Series: Event

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

Event Date
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,…
UC Ag Experts Talk Webinar Series
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Photo of a field of romaine lettuce in the Salinas Valley.
Salinas Valley Agriculture: Article

Reflections on thrips and INSV during the 2025 Lettuce Season

February 23, 2026
By Dylan J Beal, Yu-Chen Wang
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…
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Green grapes with white powdery blotches from powdery mildew

Managing Powdery Mildew

February 10, 2026
By Linda Carloni
Fungal diseases plague many different kinds of plants and their gardeners.  Fungal diseases tend to be persistent and can be difficult to manage.  Powdery mildew is one such disease.  It includes multiple fungal species and affects many different types of plants.  Powdery mildew…
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Peach leaf curl on peach tree. J. Alosi
The Real Dirt: Article

Peach Leaf Curl

November 17, 2025
If you have peach or nectarine trees, winter is the time to spray them to prevent peach leaf curl. Peach leaf curl is a fungal disease that attacks peaches and nectarines. It appears in spring, causing new leaves to become reddish, puckered and severely distorted. This disease is caused by the fungus…
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Six circular cross-sections of a tree branch showing dark staining from a Bot canker infection.

What is Bot Canker?

November 5, 2025
By Belinda Messenger-Sikes
Botryosphaeria canker, sometimes called Bot canker, is a common fungal disease that can affect many tree species including ash, eucalyptus, fig, maple, pistachio, and walnut. Plants infected with this disease typically develop cankers (dark sunken lesions in the bark) and can lose branches. The whole…
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