Lemon tree pests: the usual causes side by side
Sticky leaves, fine webbing or pale stippling all look alike from a distance, so Dr. Phyto names the likely culprit from your photo and always states how confident that reading is.
Upload a photo and start the diagnosis →Read the damage pattern before you name the pest
Three questions separate most cases. Is the surface sticky or dry? Are the marks on the leaf underside, the leaf axils or the shoot tips? And is there anything visible to the naked eye, or only discolouration?
Sticky plus a black film points to a sucking insect that excretes honeydew. Dry with fine stippling and a dusty look points to mites. Silvery scarring with tiny dark specks points in a third direction entirely. Photograph the leaf underside and one whole shoot, because the pattern across the plant carries as much information as the close up.
The six usual culprits, compared
Armoured and soft scales sit motionless on midribs, twigs and fruit stalks as small brown or shield shaped bumps. Soft scales leave the leaves sticky, armoured scales usually do not. Mealybugs hide as white cottony clusters in leaf axils and around the root collar, and they move slowly when disturbed.
Aphids cluster on the softest new growth and twist the young leaves. Spider mites leave a dry, pale stippling and, in advanced infestations, fine webbing between leaf and petiole, usually in warm dry air near a radiator or under glass. Whiteflies rise in a small cloud when the canopy is shaken and leave white scales and honeydew underneath.
The citrus leafminer is the odd one out: no honeydew at all, just silvery serpentine tunnels running through young leaves. Same tree, six very different responses, which is exactly why a name matters more than a general treatment.
What is not a pest at all
Plenty of lemon tree symptoms have nothing to do with an animal. Yellowing between green veins usually points to nutrient availability or a root zone that stays too wet. Sudden leaf drop after a move indoors is a light and temperature reaction. Brown leaf edges often follow a watering rhythm rather than an insect.
Sooty mould deserves its own note: it is a consequence, not the cause. It grows on honeydew, so it tells you a sucking insect is present or was present, and washing it off without finding the producer only buys time.
How Dr. Phyto works through it with you
You photograph the plant, answer a few follow up questions about location, watering and how long the symptoms have been developing, and you receive a named diagnosis with a confidence level attached, drawn from a verified European knowledge base rather than guesswork.
From there you get a dated, step by step plan: what to do now, what to check on which day, and which signs would mean the reading was wrong and needs revisiting. No recovery is promised. If the assessment is that the plant is beyond saving, Dr. Phyto says so plainly, because a clear ending is more useful than a hopeful one.
Products, approvals and reporting duties
This page names no plant protection product. Approvals differ from country to country, and a product cleared in one member state may be unlawful to use in the next, or cleared only for a different crop, dose or application. Ask your national plant protection authority, or speak to an agronomist, or ask us directly.
Where fruit is harvested, the pre harvest interval and residue conditions are part of the approval itself and belong on the label, so no spraying advice is worth anything without them.
One boundary is not negotiable. If the finding falls under the quarantine organisms of Regulation (EU) 2019/2072, the competent national authority has to be informed. Do not dispose of, move or sell affected material on your own initiative, and treat an uncertain suspicion as a reason to report rather than a reason to wait.
Who this is built for
Home growers with a potted lemon on the balcony, in the garden or overwintering indoors, who want a name instead of a forum argument. Professional growers in viticulture, fruit production, greenhouses and market gardening, who need the culprit identified before a block is treated.
Authorities and municipalities working with early detection and reporting duties under EU law, including from citizen photographs. And agronomists and advisors who want a fast second opinion or a differential diagnosis against their own reading.
My lemon tree leaves are sticky. Which pest is it?
Stickiness is honeydew, which several sucking insects produce: soft scales, mealybugs, aphids and whiteflies among them. The distinction comes from where the insects sit and what they look like, so photograph the leaf underside and the leaf axils. Dr. Phyto narrows it to a named culprit and states the confidence level for that reading.
Is the black coating on the leaves a disease?
Sooty mould is a secondary growth on honeydew, so it signals a sucking insect rather than a primary infection. Removing the coating alone does not resolve anything if the producer is still on the plant, which is why the diagnosis looks for the insect first.
Which spray should I use?
We do not name products. Plant protection approvals are national, and dose, crop and application are part of each approval, with pre harvest intervals where fruit is picked. Check with your national authority, consult an agronomist, or ask us directly and we will point you to the right route.
Can Dr. Phyto guarantee my tree recovers?
No, and it will not claim to. You get a named assessment with a confidence level and a dated plan you can follow and check. If the plant is beyond saving, that is said openly rather than dressed up.