San Luis Obispo County has seen more than 20 detections of Asian citrus psyllid (ACP) since January 2018, according to Citrus Insider. The majority of these invasive insects have been found in the backyards of residential properties in the city of Nipomo.

If you haven't yet heard about this insect, Asian citrus psyllids can carry and spread the incurable citrus disease huanglongbing, also called HLB or citrus greening disease. Citrus trees infected with HLB develop mottled leaves and produce misshapen fruit that stays green and tastes bitter. There is currently no treatment for the disease, which usually kills trees within three to five years.

Due to these ACP finds, citrus growers in SLO County are on high alert,...

Brown Rot

Monitor for this disease by checking for damaged fruit on your tree, as well as fruit in storage. Sometimes affected fruit develops a pungent odor and can ruin fruit held in storage. See the UC IPM web page on Brown Rot to learn more.

Citrus Leafminer

If you see what look like small “tunnels” on your citrus...

Alert from CDFA Plant Health and Prevention Services

The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have established a 94-square mile quarantine in portions of Riverside and San Bernardino counties following the detection of the citrus disease huanglongbing (HLB), or citrus greening. HLB is a deadly disease of citrus plants and closely related species, and can be transmitted from tree to tree by the Asian citrus psyllid.

On July 15, HLB was discovered in a grapefruit tree in the city of Riverside in a residential neighborhood near the intersection of Chicago...