White Powder Under Lemon Leaves: Early Powdery Mildew or Something Else?

Observation

White powdery substance under all leaves; tree otherwise healthy.

Initial Suspicion

Fungal infection (powdery mildew). However, typical powdery mildew causes chlorosis (yellowing), desiccation, and leaf drop—none seen yet. Could be very early stage.

Diagnostic Step

Use a strong magnifying glass on an affected leaf. Look for filamentous strands (mycelium) — confirms fungus. Report findings for further advice.