Asian Citrus Psyllid & Huanglongbing (HLB)
Why it matters: huanglongbing (HLB), also called citrus greening, is a deadly bacterial disease of citrus
trees. There is no cure. It is spread by a tiny insect, the Asian citrus psyllid, which is now
established across Southern California. HLB has devastated citrus in Florida, and California is working hard to keep it
from spreading here.
Know the insect: Asian citrus psyllid (ACP)
- Adults: about 1/8 inch long, mottled brown, feeding with the body tilted at a 45° angle to the leaf
- Nymphs: yellow-orange, found on tender new shoots, producing white, waxy curly tubules
- Eggs: tiny, yellow-orange, tucked into new leaf growth
- Where to look: the newest, softest growth (the "flush"), especially in spring and fall
Know the disease: HLB symptoms
- Blotchy mottle: yellowing that is uneven and doesn't match on both sides of the leaf's center vein
- Lopsided, small fruit that may stay green at the bottom and taste bitter
- Dark, aborted seeds inside the fruit
- Twig dieback and a gradually thinning canopy
Trees can carry HLB for months or years before symptoms appear, which is why prevention and early reporting matter so much.
How to protect your citrus
- Inspect monthly. Check new growth whenever your tree flushes. A hand lens helps.
- Buy certified trees. Purchase citrus only from licensed California nurseries. Never accept cuttings or budwood from unknown sources.
- Don't move citrus. Follow quarantine rules. Don't move citrus plants, leaves, or clippings out of your area.
- Handle clippings carefully. Bag or dry out pruned citrus material before disposing of it in green waste.
- Keep trees healthy. Well-watered, well-fed trees with living soil cope better with pests. See our Citrus Tree Rehabilitation guide.
- Cooperate with inspectors. State and county crews may survey or treat trees in quarantine areas to stop the spread.
Think you've found it? Report it.
California Department of Food & Agriculture (CDFA) Pest Hotline:
You can also learn more and find quarantine maps at CaliforniaCitrusThreat.org. Please don't move a suspect tree or its leaves. Call first.
How WormTRAP can help
We help homeowners and growers keep citrus strong with regular monitoring, living-soil care, worm tea programs, and land restoration planning for groves.