Citrus Greening Disease Discovered in Rancho Cucamonga


Recently, the California Department of Food and Agriculture (CDFA) has discovered Huanglongbing, also known as HLB or citrus greening disease, in Rancho Cucamonga. HLB kills citrus trees and has no cure. The disease is not harmful to humans or animals.

In a small area of the city, agricultural officials are going door-to-door to access backyard citrus trees to inspect for the presence of the Asian citrus psyllid, a small insect that feeds on citrus tree leaves, causing HLB to spread. The City of Rancho Cucamonga asks residents to cooperate with the CDFA representatives with their detection and eradication efforts. Officials will have a badge or patch indicating their affiliation with CDFA, will never ask to access the inside of the home, and will never ask for payment for their services. If trees test positive for HLB, they will be removed to prevent the spread of HLB. The removal will be done by agricultural officials at no cost.

A tiny beneficial wasp called Tamarixia radiata, is being used to reduce populations of Asian citrus psyllid in urban areas of California. Tamarixia radiata is an environmentally friendly and economical way of targeting ACP.

Treatments are the most effective way to protect citrus trees from the Asian citrus psyllid, which helps prevent the spread of HLB. Treatment is applied directly to the soil or leaves of the diseased tree. For specific questions about the treatments, please call 1-800-491-1899.

Signs of citrus greening disease are:

  • Asymmetrical patterns of yellow leaves
  • Color inversion
  • Corky veins

To help prevent the spread of HLB, the California Department of Food and Agriculture recommends the following actions:

  • Inspect your citrus trees monthly.
  • Do not move citrus plants, leaves or foliage in or out of your community.
  • Talk to your local nursery about products that can protect your tree.
  • If you suspect your tree has the disease, call the California Department of Food and Agriculture at 1-800-491-1899.

To learn more about citrus greening disease, the Asian citrus psyllid, and what you can do to help protect our California citrus trees, visit

Additional Information and Resources

Notice of Treatment (August 2021)

Proclamation of Emergency Program for Asian Citrus Psyllid and Huanglongbing (HLB) (December 2021)

Proclamation of an Emergency Program Map (December 2021)

Informational Flyer (English) (Spanish)