Is the plant disease identifier a diagnosis?

No. The symptom checker is a guide that ranks likely causes from the symptoms you select; it can't see the plant, test tissue or culture a pathogen. Use its check-first steps to confirm a cause before treating, and send samples to a plant diagnostic lab when a valuable plant or crop is at stake.

Can I identify a plant disease from a photo?

The web tools on this page don't diagnose from photos: the symptom checker works from symptoms, and the photo scanner identifies the plant's species only. The Plant Doctor in the PlantoScan app for iPhone and Android analyzes a photo of the problem and returns a health score, the likely cause and treatment steps.

Why are the leaf tips on my plant turning brown?

Brown, crispy leaf tips usually come from dry air, uneven watering or a buildup of fertilizer salts. Check the soil moisture 2 inches down and look for white crust on the soil. Thin-leaved tropical plants such as calatheas and ferns show dry-air browning first.

What does root rot look like?

Rotten roots are brown or black, soft and slimy, and their outer layer slips off when pulled, often with a sour smell. Healthy roots are firm and white to tan. Above ground, root rot shows as yellowing lower leaves and wilting even though the soil is wet.

How do you stop a plant disease or pest from spreading?

Move the affected plant away from others, remove damaged leaves into the trash rather than compost, clean scissors with rubbing alcohol between cuts, and keep leaves dry by watering at the soil. Inspect and quarantine new plants for 2 to 3 weeks before placing them with the rest.

Should I throw away a plant with pests or disease?

Most plants recover once the cause is fixed. Discard a plant when rot has reached the main stem with no healthy cuttings left, when a heavy infestation keeps returning after several weeks of treatment, or when a bacterial infection is spreading quickly through a collection.

Plant Disease Identifier: What's Wrong With My Plant?

The plant disease identifier ranks the likely causes of a sick plant from the symptoms you see, then lists what to check and what to do. A houseplant with yellow lower leaves that wilts while its soil is still wet points first to overwatering and root rot, not thirst — the checker below starts with exactly that example. It covers 32 symptoms and 23 causes across watering, light, nutrients, fungal and bacterial disease, and pests.

1. Where is the plant growing?

2. How does the soil feel 2 in (5 cm) down?

3. What do you see? Pick every symptom that fits.

Most likely causes

1Overwatering and root rotStrong matchWatering · matches yellow older, lower leaves; wilting or drooping leaves
Soil that stays wet starves roots of oxygen, and rot fungi move in. The plant wilts even though it has water, because damaged roots can no longer take it up.
Check first
- Push a finger or wooden skewer 2 in (5 cm) into the soil. Wet, cool soil several days after watering points to overwatering.
- Slide the plant out of its pot. Healthy roots are firm and white to tan; rotten roots are brown or black, slimy, and the outer layer slips off.
- Confirm the pot has a drainage hole and isn't standing in a saucer of water.
What to do
- Stop watering until the top 1–2 in (2.5–5 cm) of soil is dry — fully dry for succulents and cacti.
- If roots are rotten, trim every soft root with clean scissors and repot into fresh, well-draining mix in a pot with drainage, sized to the remaining healthy roots.
- Skip fertilizer until new growth appears. If the stem base is mushy, root healthy cuttings as a backup.
2Fungus gnatsLikelyPest · matches wilting or drooping leaves
Fungus gnats are small dark flies about 1/8 in (3 mm) long that breed in constantly moist potting mix. Adults are harmless; larvae can damage seedlings and cuttings.
Check first
- Weak-flying gnats rise from the soil when you water or move the pot.
- A yellow sticky card or a slice of raw potato on the soil for a day shows adults and larvae.
What to do
- Let the top 1–2 in (2.5–5 cm) of soil dry between waterings, or water from below.
- Trap adults with yellow sticky cards and treat larvae with a soil drench containing Bti (Bacillus thuringiensis israelensis).
3Fertilizer burn or salt buildupPossibleNutrition · matches yellow older, lower leaves; wilting or drooping leaves
Excess fertilizer salts and hard-water minerals collect in the soil and draw water out of the roots, which scorches leaf tips and margins.
Check first
- Look for a white or yellowish crust on the soil surface or the pot rim.
- Think back: fertilizer at full strength, fertilizer on dry soil, or feeding through winter all raise salt levels.
What to do
- Flush the soil: run about 2–3 times the pot's volume of water through it and let it drain fully.
- Resume feeding at half the label rate during active growth only. Repot into fresh mix if the crust returns quickly.
4Root-bound plantPossibleEnvironment · matches yellow older, lower leaves; wilting or drooping leaves
When roots fill the pot, water runs straight through, the plant dries out within a day or two, and growth slows.
Check first
- Roots poke out of the drainage hole or circle densely around the root ball when you unpot it.
- The plant needs water far more often than it used to.
What to do
- Repot into a pot 1–2 in (2.5–5 cm) wider in spring or early summer.
- Gently loosen circling roots and use fresh potting mix suited to the plant.
5Relocation or transplant shockPossibleEnvironment · matches yellow older, lower leaves; wilting or drooping leaves
Moving, repotting or bringing a plant home from the store changes its light, temperature and humidity at once. Figs in particular often drop leaves in response.
Check first
- The plant was moved, repotted or bought within the last 2–4 weeks.
- Roots are firm and healthy and there are no pests or spots.
What to do
- Pick a good spot and leave the plant there; keep watering consistent.
- Skip fertilizer for 4–6 weeks. New leaves are the sign it has settled in.

A symptom guide, not a lab diagnosis: several problems can look alike, and more than one can happen at once. Confirm with the “check first” steps before treating.

How Do You Identify What Is Wrong With a Plant?

Work from the plant outward: name the species, note where the damage starts, check soil moisture and roots, look for pests under leaves, and recall recent changes. Most houseplant problems turn out to be watering, light or humidity rather than infectious disease.

1Name the plant. Care needs differ hugely: wet soil that rots a succulent suits a fern. Identify the species first.
2Map the damage. Note whether symptoms start on old or new leaves, one side or the whole plant, leaves or stems.
3Check soil and roots. Push a finger 2 in (5 cm) into the soil, then slide the plant from its pot and look at the roots.
4Look for pests. Use a magnifier on leaf undersides and leaf joints, and tap leaves over white paper.
5Recall recent changes. Moves, repotting, cold nights, missed waterings and fresh fertilizer explain many sudden problems.

Where the symptom starts matters as much as what it looks like. Plants pull mobile nutrients such as nitrogen out of old leaves to feed new ones, so shortages show on the oldest leaves first, while iron shortages show on the newest. Pests such as aphids and thrips go for soft new growth, and cold or sun damage appears on the side that faced the window.

What Do Yellow Leaves on a Plant Mean?

Yellow leaves usually mean a watering problem: lower leaves yellowing in wet soil point to overwatering and root rot, and in dry soil to underwatering. Yellow new leaves with green veins suggest iron deficiency, and one old leaf yellowing slowly is normal aging.

Yellowing pattern	Most likely cause	Check first
Oldest lower leaves, soil wet for days	Overwatering or root rot	Unpot and inspect the roots
Oldest lower leaves, soil bone dry	Underwatering or a root-bound plant	Check how fast the pot dries out
Oldest leaves evenly pale, no feeding for months	Nitrogen deficiency	Rule out wet soil first
Newest leaves yellow, veins stay green	Iron deficiency, often from high pH	Test soil or water pH
One or two bottom leaves, new growth healthy	Normal leaf aging	No action needed
Yellow with fine speckles or webbing	Spider mites	Tap test over white paper
Whole plant pale and stretched	Too little light	Measure distance to the window
Sudden yellowing and drop after a move	Relocation shock	Keep conditions steady

Nutrient problems are the least common cause indoors, and fertilizer won't help a plant whose roots are rotting. Rule out water and light first; if a plant has gone unfed for a year, a fertilizer calculator for dilution and application rates helps you feed at the right strength instead of guessing.

Is It a Disease, a Pest or a Care Problem?

Care problems follow a change and affect the plant in a pattern; diseases show as spots, powder or rot that multiplies and spreads; pests leave insects, eggs, webbing or sticky honeydew you can see with a magnifier. The table below separates the three.

Clue	Care problem	Fungal or bacterial disease	Pests
Pattern	Whole plant, one side, or oldest leaves first	Scattered spots that multiply and merge	Damage on new growth and leaf undersides
Spreads to other plants	No	Yes, by splashing water and tools	Yes, by crawling or flying
Timing	Follows a move, repot, cold snap or watering change	Follows wet leaves and humid weather	Follows a new plant or time outdoors
How to confirm	Soil moisture and root check	Rings, halos, powder or ooze under a magnifier	Insects, eggs, webbing or honeydew

Brown, crispy leaf edges on calatheas, ferns and other humidity-loving plants are almost always dry air, not disease. Pale, leggy growth that leans toward a window is a light shortage; a DLI calculator for indoor light shows how much light a spot really delivers.

How Do You Identify Common Plant Pests?

Most houseplant pests are 1/25 to 1/4 inch (1–6 mm) long and hide under leaves or in leaf joints. Spider mites leave stippling and webbing, mealybugs white cotton, scale brown bumps, aphids sticky clusters, thrips silver streaks and fungus gnats flies over wet soil.

Pest	Size	Where it hides	Telltale sign
Spider mites	About 1/50 in (0.5 mm)	Leaf undersides	Pale stippling, fine webbing
Aphids	1/16–1/8 in (1.5–3 mm)	Shoot tips and buds	Soft clusters, sticky honeydew, white shed skins
Mealybugs	About 1/8 in (3 mm)	Leaf joints, undersides, roots	White cottony wax
Scale	About 1/16–1/4 in (2–6 mm)	Stems and leaf midribs	Immobile bumps, sticky leaves below
Fungus gnats	About 1/8 in (3 mm)	Soil surface	Weak-flying dark gnats, larvae in wet mix
Thrips	About 1/25 in (1 mm)	Flowers and both leaf faces	Silvery streaks with black specks
Whiteflies	About 1/16 in (1.5 mm)	Leaf undersides	White cloud rises when the plant is shaken

A 10× hand lens and a sheet of white paper confirm most pests: hold the paper under a leaf, tap the leaf, and watch for specks that move. Sticky leaves or a sticky floor under the plant mean sap-feeding insects — aphids, mealybugs, scale or whiteflies — even before you spot them. Isolate any infested plant before treating it.

Why Should You Identify the Plant First?

The same symptom means different things on different plants: soil that stays moist for a week is ideal for a fern but rots a cactus. Identify the species first, then compare its care needs with how you've been watering, lighting and feeding it.

Scan a clear photo of a healthy leaf below to name the plant. This web scanner identifies the species only — it does not diagnose disease — and includes 3 free scans. For leafy indoor plants, the houseplant identifier adds look-alike checks; for fleshy and spiny plants, the succulent identifier does the same. The general plant scanner handles garden plants and trees, and a known name goes straight into the plant care lookup by name.

Checking your free scans…

Snap or upload a plant photo

Get the clearest result from a sharp, close-up photo of one leaf, flower or the whole plant in good light.

…or drag & drop an image here

Diagnose from a photo with the Plant Doctor

The PlantoScan app for iPhone and Android includes a Plant Doctor: photograph the problem and get a health score, the likely cause and step-by-step treatment, with health checks saved per plant so you can see whether it recovers.

When Should You Get a Lab Diagnosis?

Get a lab diagnosis when a problem spreads through a vegetable garden, orchard, lawn or several trees, when a valuable plant keeps declining after care fixes, or before using a fungicide on food crops. Plant diagnostic labs identify the exact pathogen.

Most US states run a plant diagnostic clinic through their land-grant university's Cooperative Extension service, and county Extension offices can explain how to collect and ship a sample; the USDA National Institute of Food and Agriculture (NIFA) keeps a directory of the Extension service in each state. Send a sample that shows both healthy and damaged tissue, rather than a completely dead plant.

Frequently Asked Questions

Is the plant disease identifier a diagnosis?: No. The symptom checker is a guide that ranks likely causes from the symptoms you select; it can't see the plant, test tissue or culture a pathogen. Use its check-first steps to confirm a cause before treating, and send samples to a plant diagnostic lab when a valuable plant or crop is at stake.
Can I identify a plant disease from a photo?: The web tools on this page don't diagnose from photos: the symptom checker works from symptoms, and the photo scanner identifies the plant's species only. The Plant Doctor in the PlantoScan app for iPhone and Android analyzes a photo of the problem and returns a health score, the likely cause and treatment steps.
Why are the leaf tips on my plant turning brown?: Brown, crispy leaf tips usually come from dry air, uneven watering or a buildup of fertilizer salts. Check the soil moisture 2 inches down and look for white crust on the soil. Thin-leaved tropical plants such as calatheas and ferns show dry-air browning first.
What does root rot look like?: Rotten roots are brown or black, soft and slimy, and their outer layer slips off when pulled, often with a sour smell. Healthy roots are firm and white to tan. Above ground, root rot shows as yellowing lower leaves and wilting even though the soil is wet.
How do you stop a plant disease or pest from spreading?: Move the affected plant away from others, remove damaged leaves into the trash rather than compost, clean scissors with rubbing alcohol between cuts, and keep leaves dry by watering at the soil. Inspect and quarantine new plants for 2 to 3 weeks before placing them with the rest.
Should I throw away a plant with pests or disease?: Most plants recover once the cause is fixed. Discard a plant when rot has reached the main stem with no healthy cuttings left, when a heavy infestation keeps returning after several weeks of treatment, or when a bacterial infection is spreading quickly through a collection.

Symptom and cause descriptions are written by the PlantoScan team from general horticultural practice. They are a guide, not a laboratory diagnosis; always follow the label of any treatment product. The checker is one of PlantoScan's free plant and garden tools.