Asian Citrus Psyllid
Diaphorina citri
A tiny mottled-brown sap-sucking insect that feeds on the new growth of citrus and close relatives. Its real importance is as the vector of huanglongbing, or citrus greening, an incurable bacterial disease that has devastated citrus worldwide.
🔎 How to spot it
Adults are about an eighth of an inch long with a mottled brown body and a light brown head, and they feed with the head down and the body tilted up at roughly a thirty degree angle, a posture unlike most other insects. Nymphs are yellowish orange with large wing pads and produce white waxy tubules. Eggs are tiny, almond shaped, and pale yellow to orange, tucked into unfurling new leaves.
🥀 Damage it causes
Direct feeding by nymphs twists and curls new leaves, but the main threat is disease transmission. The psyllid spreads the bacterium that causes huanglongbing, which produces blotchy yellow leaves, lopsided bitter green fruit, twig dieback, and eventual tree death. Once a tree is infected there is no cure, so blocking the psyllid is the only protection.
🛡️ Prevent it
Inspect new flushes of growth for the angled adults and waxy nymphs, especially in spring and summer. Buy only certified, pest-free citrus and never move citrus plants or cuttings out of quarantined areas, since long-distance spread happens through infested nursery stock. Remove and report trees showing greening symptoms so they do not serve as reservoirs.
🧯 If it is already here
On dooryard trees, horticultural oils and insecticidal soaps reduce nymphs on tender flush, and the parasitic wasp Tamarixia radiata attacks nymphs as a biological control. Where greening is present, area-wide and regulatory programs guide treatment. Keeping new growth protected during flushes is the practical home goal.
💡 Good to know
In the United States, areas with the psyllid are under quarantine, and it carries the Asian form of the greening bacterium found in Florida. It completes nine to ten generations a year with no true winter dormancy, so populations rebound quickly. A single feeding bout of an hour or more can transmit the pathogen.
🌱 Plants it attacks
14 plants in the library can be attacked by this pest
For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.