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Effects of Drought and Botryophaeria Fungi on Permanent Crops

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).


“For more information on the Asian Citrus Psyllid, please click on “Exotic Pest” above”

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. 


Topics in Subtropics Blog
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PEST ALERT - Black Fig Fly

Avocado: Food of the Gods

Watch this video (in Spanish here) on Avocado Fruit Production. California is the biggest avocado producer nationwide; this delicious, versatile fruit arrived in the state in the 1890s. The demand for avocados has increased substantially over the last couple of decades. Nevertheless, avocado production faces many challenges.

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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