Citrus Greening Disease Discovered in Rancho Cucamonga

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.

A tiny insect no bigger than a grain of rice may go unnoticed on your citrus trees, but it could have devastating consequences for California citrus if not stopped. The Asian citrus psyllid feeds on citrus leaves and stems, and can infect citrus trees with a bacteria that causes a serious plant disease called Huanglongbing, also known as HLB or citrus greening disease. 

The best way to protect citrus trees from HLB is to stop the Asian citrus psyllid. Once a tree is infected with HLB, it will die. Diseased trees need to be removed in order to protect other citrus trees on the property, neighbors’ trees and the community’s citrus.

If you think you have spotted the pest or disease, call the free statewide pest hotline at 800-491-1899.

Signs of citrus greening disease are:

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

The California Department of Food and Agriculture tracks the presence of the pest and disease, and establishes quarantines to help protect California citrus trees. The citrus quarantine prohibits the movement of all citrus nursery stock or plant material out of the affected area. Provisions exist to allow the movement of commercially cleaned and packed citrus fruit.  

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

Proclamation of Emergency Program for Asian Citrus Psyllid and Huanglongbing (HLB) (December 2023)

Map of Treatment Area

Map of Citrus Greening Disease notice of treatment area Rancho Cucamonga and Ontario

Informational Flyer (English) (Spanish)