Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

We are San Diego & Riverside County Farm Advisors

HLB - Potential Threat Near San Diego County

HLB detected in Riverside County: 

The Asian citrus psyllid is a tiny, mottled brown insect about the size of an aphid that poses a serious threat to all of California's varieties of citrus (e.g., oranges, grapefruit, lemons, and mandarins).


The insect is associated with the fatal citrus disease Huanglongbing (HLB), also called citrus greening disease. The psyllid takes the bacteria into its body when it feeds on bacteria-infected plants and spreads when a bacteria-carrying psyllid flies to a healthy plant and injects bacteria into it as it feeds.

HLB can kill a citrus tree in as little as five years, and there is no known cure. All commonly grown citrus varieties are susceptible to the disease.

The only way to protect trees is to prevent spread of the HLB pathogen in the first place, by controlling psyllid populations and removing and destroying any infected trees.

Learn more about HLB and how to protect your crops from it by following these links. 


News Stories: 

Distribution & Management: 

IPM Blog: 

IPM Pest Notes 

California Citrus Pest & Disease Prevention Committee: 

Topics in Subtropics Blog

  • ACP-HLB Update

    Added April 20, 2018
    ACP adult and nymph

      Citrus Grower Workshop REMINDER (April 26) Dr. Beth Grafton-Cardwell will present findings from her continuing survey of ACP populations across Ventura County, including data on the effects of pesticide treatments on ACP...

  • Avocado Collapse!

    Added April 20, 2018
    avocado verticillium

    It's that time of year to see some drama in avocado orchards. Once healthy-looking trees can suddenly turn brown in a weekend and all the surrounding trees still look fine. And it can be quite common in some years along the coast. The winter weather will...

  • Insectary Plantings, Think About Them.

    Added April 19, 2018
    insectary plants

    Home is where the habitat is: This Earth Day, consider installing insectary plants —Stephanie Parreira, UC Statewide IPM Program Help the environment this Earth Day, which falls on Sunday April 22 this year, by installing insectary plants! These...

  • Make More Avocado Fruit

    Added April 19, 2018
    avocado fruit

    Use of ProgGibb LV Plus® Plant Growth Regulator Increases Total Yield/                            Fruit Size of...

  • Area-Wide Treatments for Ventura ACP

    Added April 18, 2018
    ACP adult and nymph

    For the past 18 months, a team led by University of California research entomologist Beth Grafton-Cardwell has been conducting an Asian citrus psyllid monitoring project to determine the efficacy of Ventura County's area-wide ACP...

  • Mulch. Read Some About It!

    Added April 18, 2018

    Two questions and comments came up last week about the use of mulch in orchards. The first is that mulch is two edged. It serves to combat erosion and root rot, but it can also burn. Mulch and wood piled up against tree trunks and near trunks can cause...

Avocado Production in California Books

Book 1: Background Information

In Book 1, Gary S. Bender, Farm Advisor, takes you through the history of the avocado industry in California and teaches you about grove development.

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Book 2: Cultural Care

Book 2 focuses on cultural care and includes articles on irrigation, fertilization, disease and insect control, vertebrate pest management, pruning and frost management. The author for most of the articles is Gary S. Bender, Farm Advisor for Subtropical Horticulture in San Diego County.

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