- Author: Margaret J O'Neill
Do you have citrus in your yard? This is the time of year that the Asian Citrus Psyllid (ACP) is most active in San Bernardino County when trees are sending out their fall “flush” of new growth. Asian Citrus Psyllids (also called ACP) spread the bacteria that causes citrus greening disease (also called HLB, Hunaglongbing). While this bacterium does not harm people is deadly to citrus (all types from kumquats to grapefruit and everything in between).
Unfortunately, there is currently no cure available to the public for HLB spread by the ACP. The only way to control the disease is to reduce the spread of ACP and be vigilant about removing trees that are infected or near infected trees. Keeping ants out of your trees is a great first step to protecting your trees from ACP and other pests. Since ants protect pests that excrete sugar solution from beneficial predators like lady beetles, praying mantis and syrphid fly larvae, keeping them out gives these “good bugs” a chance to help keep ACP out. Another key step to preventing the spread of HLB and ACP is to remove all stems and leaves from citrus you are going to share and to wipe fruit off to keep ACP from hitching a ride on fruit or plant material. To learn more about the ACP/HLB complex, view a map of its spread, and watch a four-minute video visit: https://ucanr.edu/sites/ACP.
Thanks to a wide array of UC ANR scientists for sharing the following photos.
Symptoms: An early sign of infection are chlorotic (yellow) leaves.
Remember that yellow leaves may also be due to nutrient deficiencies and it is important to recognize the differences. While nutrient deficiencies result in a consistent yellowing pattern on both sides of the leaf, HLB causes blotchy yellow areas that are asymmetrical (different on the right and left side of the leaves), although these symptoms can take 9 months to several years to show up in an infected tree. The delay in visual symptoms is the reason it is very important not to share any citrus cuttings with friends and family. A healthy-looking tree can still be infected. There are clean sources of cuttings (budwood) available through the Citrus Colonial Protection Program (CCPP: https://ccpp.ucr.edu/)
Later Symptoms: Misshapen fruit, with an asymmetrical midline and discolored malformed seeds. These fruits, while not harmful to us, will be bitter and inedible.
An early sign of ACP infestation are leaves that have a “notch” (indicates ACP feeding) or larvae that create waxy tubules.
ACP life stages: The adult is about the size of a half a grain of rice and feeds at a 45-degree angle which is a distinguishing feature from other common citrus pests. The juvenile (nymph) phase is golden in color, with bright red eyes and can be found on the new growth (flush) of citrus leaves.
To learn more about the ACP/HLB complex, view a map of its spread, and watch a four-minute video visit: https://ucanr.edu/sites/ACP. Want to learn more or have questions? Attend our class on Nov 28th from 10:30 to 11:30 to learn more about this deadly pest. To register: http://mgsb.ucanr.edu/?calitem=494190