Asian Citrus Psyllid

Asian Citrus Psyllid citrus insect diagram

The Grim Reaper of Citrus Trees

If you love Citrus trees beware, this Halloween the grim reaper will not be wearing a black robe and carrying a scythe… And it may be providing more of a trick than a treat! The Grim Reaper of citrus trees is a tiny, flying, sap-sucking insect the size of a grain of rice. The Asian Citrus Psyllid (ACP) can cause damage on its own, but also may infect our trees with a fatal bacterium that causes Citrus Greening disease, technically known as Huanglongbing disease (HLB). This disease has devastated the Florida citrus industry and has now been found in Southern California. While not harmful to humans, the disease kills citrus trees, and has no cure.

Monitoring citrus for the presence of the ACP and symptoms of HLB is key for controlling this fatal disease. Much like aphids, the psyllids feed on new, developing leaves. Check new growths on your trees for psyllid activity, especially during Spring and Fall. Look for evidence of the ACP in new growth by checking for:

  • Adult psyllids feeding, head down and rear end in the air (at a 45-degree angle)
  • Twisted and or notched leaves in new growth
  • Sticky honeydew with black sooty mold
  • Nymphs (baby insects) that produce waxy, white tubules
  • Tiny, almond shaped, yellow eggs (You may need Inspector Clouseau’s magnifying glass)

Once a tree is infected with HLB, it will die. Diseased trees need to be removed promptly in order to protect other citrus trees on the property, in neighbors’ yards, and throughout the community from getting infected. If you think you have spotted the pest or disease, call the free statewide pest hotline at 800-491-1899.

You can help protect your own trees by controlling ants that directly interfere with biological control of ACP. Ants farm the psyllid for honeydew. Ants feed honeydew to their offspring and protect the psyllids from natures beneficial predators and parasites. There are some “fruit safe” chemicals and home remedies that can help protect and to kill ACP insects before they infect the tree. However, we need to be very careful not to use these when the trees are flowering, because they can kill honeybees and beneficial insects. These methods, if used, need to be done on a very short and consistent time frame- so I would usually suggest going this route only if trees were found in your neighborhood with the disease.
Always purchase your trees from a trusted source. At Garden View Nursery, all our citrus trees are grown and kept safe in quarantine zones in screen houses inspected by the Department of Agriculture.