Yellow citrus leaves are a symptom, not a diagnosis. In Southern California, the pattern of yellowing matters: uniform yellowing, green veins, blotchy mottling and yellowing paired with leaf drop can point in different directions.
Start with the pattern
Check whether symptoms are on old or new leaves, whether both sides of the midrib look similar, and whether the tree is also wilting, dropping leaves or producing poor fruit. Review irrigation before assuming fertilizer is the answer.
Common possibilities
Possibilities include nutrient problems, overly wet or dry roots, salinity, root damage and sap-feeding pests. Asymmetrical blotchy mottling can also be associated with huanglongbing (HLB), so suspicious citrus symptoms deserve careful identification rather than guesswork.
What to do next
Photograph several leaves, inspect new growth and leaf undersides, check soil moisture and irrigation coverage, and compare affected and healthy branches.
California reference
For California citrus diagnostics, see UC IPM citrus leaf-damage resources and UC IPM ACP & HLB guidance.
Related citrus guides
- Citrus leafminer: winding mines and curled leaves
- Asian citrus psyllid & HLB
- How often to water citrus in Southern California
Need help with your fruit tree in South Orange County?
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On-site Plant Health Diagnostic: $150. Treatment, repairs and laboratory testing are quoted separately.
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