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Medium Priority Disease

Leaf Spots Diagnosis

Identify leaf spots by pattern, color, and spread. Compare fungal, bacterial, sun, pest, viral, and chemical damage with treatment steps.

Leaf Spots Diagnosis example

Quick answer

Most cases come down to pattern, spread, and urgency.

For spots, patches, specks, or discolored marks on plant leaves, match the visible pattern first, then check whether the cause is environmental, watering-related, pest-related, disease-related, or part of normal plant growth.

Diagnosis Tips

  • Photograph spot size, color, borders, and spread so you can compare changes over time.
  • Avoid wetting foliage while you diagnose because moisture helps many infections spread.
  • Use sterile scissors and isolate the plant if spots are wet-looking, spreading, or ringed with yellow.
Round Brown Spots with Yellow Halos diagnosis pattern
High Priority

Primary cause: Fungal infection

Round Brown Spots with Yellow Halos

Circular brown or black spots surrounded by yellow rings, often with defined borders.

Common causes

High humidity with poor air circulationWater on leavesFungal sporesContaminated soil

Treatment steps

  1. 1 Remove affected leaves immediately with sterile tools
  2. 2 Improve air circulation significantly
  3. 3 Water soil directly, avoid getting leaves wet
  4. 4 Apply fungicide spray if spreading
  5. 5 Increase spacing between plants

When to worry

Fungal spots spread rapidly - immediate action prevents total infection.

Commonly affected plants

Tropical plantsHigh-humidity plantsCrowded plantsOverwatered plants
Water-Soaked Dark Spots diagnosis pattern
High Priority

Primary cause: Bacterial infection

Water-Soaked Dark Spots

Dark, wet-looking spots that appear water-soaked, often with irregular edges and rapid spread.

Common causes

Bacterial pathogensWounds or damage to leavesHigh moisture conditionsPoor sanitation

Treatment steps

  1. 1 Isolate plant immediately
  2. 2 Remove all affected leaves with sterile scissors
  3. 3 Apply copper-based bactericide
  4. 4 Drastically reduce watering
  5. 5 Improve ventilation and reduce humidity

When to worry

Bacterial infections can kill plants quickly - act within hours.

Commonly affected plants

Soft-leaved plantsRecently damaged plantsHigh-humidity environments
Dry Brown Spots with Crispy Edges diagnosis pattern
Low Priority

Primary cause: Sunscald or heat damage

Dry Brown Spots with Crispy Edges

Dry, papery brown spots, often on leaves facing the sun or heat source.

Common causes

Direct intense sunlightHeat stressSudden light increaseMagnification through water drops

Treatment steps

  1. 1 Move to location with bright, indirect light
  2. 2 Gradually acclimate to brighter conditions
  3. 3 Avoid watering when sun is intense
  4. 4 Provide afternoon shade if outdoors
  5. 5 Remove severely damaged leaves

When to worry

Only if spots continue forming after environmental adjustment.

Commonly affected plants

Shade plants in sunRecently moved plantsPlants with water droplets in sun
Small Black Specks diagnosis pattern
Medium Priority

Primary cause: Sooty mold

Small Black Specks

Tiny black specks or powdery coating, often on sticky honeydew from insects.

Common causes

Aphid or scale insect honeydewPoor air circulationHigh humidityNeglected pest problems

Treatment steps

  1. 1 Treat underlying pest problem first
  2. 2 Gently wash leaves with mild soap solution
  3. 3 Improve air circulation around plant
  4. 4 Apply neem oil to prevent recurrence
  5. 5 Monitor closely for pest resurgence

When to worry

If black coating spreads rapidly or pests aren't controlled.

Commonly affected plants

Plants with pest problemsIndoor plants with poor air flowSticky plants
Pale Spots with Dark Borders diagnosis pattern
Medium Priority

Primary cause: Viral infection

Pale Spots with Dark Borders

Light-colored or pale spots with darker borders, sometimes creating mosaic patterns.

Common causes

Viral pathogensInsect vectors (aphids, thrips)Contaminated toolsInfected plant contact

Treatment steps

  1. 1 Isolate plant immediately
  2. 2 No cure available - focus on prevention
  3. 3 Control insect vectors aggressively
  4. 4 Disinfect all tools between plants
  5. 5 Consider removing severely affected plants

When to worry

Viral infections are incurable and can spread to other plants.

Commonly affected plants

Plants with insect problemsNew plants from unknown sourcesStressed plants
Irregular Yellow-Brown Patches diagnosis pattern
Medium Priority

Primary cause: Chemical damage

Irregular Yellow-Brown Patches

Irregular patches of discoloration, often following spray patterns or droplet marks.

Common causes

Cleaning product contactFertilizer burnPesticide phytotoxicityWater quality issues

Treatment steps

  1. 1 Rinse leaves thoroughly with clean water
  2. 2 Identify and remove chemical source
  3. 3 Improve ventilation to help recovery
  4. 4 Avoid spraying in direct sunlight
  5. 5 Use only plant-safe products in future

When to worry

If chemical damage spreads or affects plant growth points.

Commonly affected plants

Recently sprayed plantsPlants near cleaning areasOver-fertilized plants

Related Plant Clinic Guides

Compare nearby symptoms if this pattern does not exactly match your plant.

Medium Priority Watering

Yellow Leaves

Leaves turning yellow, fading, or dropping earlier than expected.
Low Priority Environment

Brown Leaf Tips

Leaf tips turning brown, dry, or crispy while the rest of the plant survives.
High Priority Pests

Pest Infestation

Small insects, webbing, sticky residue, or moving specks on leaves and soil.