Field Identification
Huanglongbing (HLB): a phloem-limited bacterium spread chiefly by Asian citrus psyllid, causing blotchy mottled leaves, twig dieback, small lopsided fruit with aborted seeds, and eventual tree decline. There is no cure—management is vector and nutrition pressure.
Asymmetrical yellow blotches crossing veins, corky midribs on fruit, and zinc-like deficiency patterns on one side of the canopy only. Lab PCR confirms suspect trees because nutrient stress can mimic early signs.
How to Deal With It
Organic Control Methods
Copper, neem, or soap-based sprays targeting psyllid adults and nymphs on flush—timed to new growth flushes; surround sprays on borders may help in small plantings.
Tamarixia radiata and Diaphorencyrtus aligarhensis parasitoid wasps attack psyllid nymphs in classical programs; generalist predators include lady beetles and lacewings.
Remove infected trees in regulated areas when required; optimize irrigation and controlled nutrition to keep productive trees functioning longer in endemic regions.
Screen houses exclude psyllids for high-value young trees; sticky traps monitor movement.
Only plant certified disease-free budwood; scout every flush for psyllid eggs and nymphs on tender leaves.
Let Nature Handle It
Natural Enemies
- Tamarixia radiata
- Diaphorencyrtus aligarhensis
- Lady Beetles
Threat Map