Citrus psylla
A tiny sap-sucker on citrus flush — and the vector of citrus greening (HLB), the incurable disease that makes it the pest to fear most.
- Pest type
- Sap-sucking psyllid
- Attacks
- Tender new flush
- Worst in
- Flush periods; young trees
- Main risk
- Spreads citrus greening (HLB)
Overview
Citrus psylla is a small (2–3 mm) sap-sucking psyllid that feeds on the tender new flush of citrus, sitting at a characteristic angle with the rear end raised. Its direct feeding curls and distorts the young leaves and shoots, and its honeydew brings sooty mould — but that is not why it is the most important citrus pest.
Citrus psylla is the insect vector of citrus greening or Huanglongbing (HLB), a bacterial disease with no cure that slowly kills citrus trees and has devastated the crop in many regions. A psylla that feeds on an infected tree carries the bacterium to healthy trees, so managing the psylla is the front line of protecting an orchard from greening. Control therefore aims at keeping psylla off the new flush, especially on young plants and near any greening-affected trees.
How to identify it
- Tiny (2–3 mm) brownish psyllids on the tender new flush, resting at a slanted angle with the tail end lifted up.
- Yellow-orange nymphs on the new growth, producing waxy threads and honeydew.
- Curled, twisted young leaves and shoots on the flush, with sooty mould on the honeydew.
- On trees with greening, look also for the disease signs — blotchy mottled leaves and lopsided, poorly-coloured fruit.
The damage it does
- Direct feeding that curls and distorts the new flush and weakens young trees.
- Honeydew and sooty mould on leaves and fruit, cutting photosynthesis and quality.
- Above all, transmission of citrus greening (HLB) — an incurable, tree-killing bacterial disease — which is the real and far larger threat.
- Rapid spread of greening through an orchard when psylla is uncontrolled and infected trees are present.
When to act
- Protect every new flush, when the psylla concentrates and feeds — especially on young, frequently-flushing plants.
- Be most vigilant near any greening-affected trees, and monitor the flush closely there.
- Because the disease risk is what matters most, keep psylla numbers very low rather than tolerating a threshold.
Organic & cultural control
- Use only certified disease-free planting material, and remove and destroy greening-affected trees promptly — a source tree keeps re-infecting the rest.
- Conserve natural enemies (the parasitoid Tamarixia and ladybird predators are important on citrus psylla) by avoiding unnecessary broad-spectrum sprays.
- Spray neem on the new flush to check the psylla, and manage flushing so it is more uniform and easier to protect.
- Coordinate area-wide, since greening and psylla move between orchards.
Chemical control
- Protect the new flush with a CIB&RC-registered insecticide for citrus psylla, timed to flush emergence, and keep young plants especially well protected.
- Rotate insecticide groups to avoid resistance, and combine chemical control with removing greening-source trees — spraying alone cannot stop the disease if infected trees remain.
- Observe the pre-harvest interval on the fruit.
- Confirm the current recommendation and schedule for your area with your local KVK or horticulture department.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
Why is citrus psylla considered so serious if it is such a small insect?
Because it spreads citrus greening (Huanglongbing / HLB), a bacterial disease with no cure that slowly kills citrus trees. The psylla’s own feeding damage is minor next to that. A psylla that feeds on a greening-infected tree carries the bacterium to healthy trees, so controlling the psylla — and removing infected trees — is the front line against the disease.
How do I protect my citrus from greening through the psylla?
Plant only certified disease-free saplings, remove and destroy any greening-affected trees promptly (they keep infecting the rest), and keep psylla numbers very low by protecting every new flush with neem and rotated registered insecticides, while conserving its natural enemies. Because both the psylla and the disease move between orchards, area-wide coordination matters.
Can spraying alone stop citrus greening?
No. Spraying reduces the psylla that spreads greening, but if infected source trees remain in or near the orchard, the disease keeps being picked up and passed on. You must combine psylla control with removing greening-affected trees and using disease-free planting material — control of the vector and the source together, not spraying alone.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.