Botanic Garden >> Gardening > >> Question and Answer >> Plant Diseases

Tiny Spots on Meyer Lemon Fruit: Greasy Spot Fungus

Small spots on Meyer lemon fruit with healthy foliage likely indicate greasy spot (Mycosphaerella citri)—a minor fungal disease that's cosmetic, not destructive.

Greasy Spot Characteristics

Yellowish-brown to black specks on fruit rind
May feel slightly greasy or raised
Does not penetrate flesh or affect flavor
More prevalent in wet, humid conditions
Rare on Meyer lemon but possible

Management

Cultural:

Remove fallen leaves (major spore source)
Improve air circulation with pruning
Avoid overhead irrigation

Chemical (if needed): Copper fungicides or horticultural oil applied per label in spring/summer. Usually unnecessary for home trees.

Overall Tree Health

Focus on basics: slow-release citrus fertilizer, clean mulch-free zone around trunk, consistent watering. Atomic Grow and similar biostimulants may enhance vigor but aren't essential. Greasy spot won't kill your tree or ruin the harvest.

Plant Diseases: Meyer Lemon Tiny Black Fruit: Normal Abortion or Transplant Shock?; Meyer Lemon Fruit Scarring: Insect Identification and Pre-Harvest Timing; Meyer Lemon Fruit Drop: Post-Bloom Stress and Fungus; Diagnosing Brown, Hard Meyer Lemon Fruit in Mature Trees; Mature Meyer Lemon Decline: Root Rot from Flooding Suspected; Meyer Lemon Fruit Problems: Discoloration, Rot Smell, and Rust Mites; Identifying Fruit Problems on Meyer Lemon Trees; White Spots on Meyer Lemon: Powdery Mildew or Insect Infestation?; Diagnosing Lemon Tree Issues: Scale, Fruit Spots, and Mysterious Grey Coating; Why Mature Meyer Lemon Drops Fruit in Summer

Garden Articles

Investigating Yellowing Leaves and Scale on Meyer Lemon in Hawaii

Meyer Lemon Immediate Fruit Yellowing: Post-Bloom Fruit Drop

Scale Insects and Ants on Meyer Lemon: Integrated Control for a Healthy Tree

Meyer Lemon Fruit Drop: Repot and Prune to Balance Roots

Meyer Lemon Leaf Loss in Florida: Fertilize Regularly

Caring for a Container Meyer Lemon Tree: Pruning Blooms, Repotting, and Winter Protection

Thinning Meyer Lemon Fruit for Larger, Juicier Lemons

Plants

Spider Mites on Indoor Meyer Lemon: Control and Repotting Decisions

Meyer Lemon Fruit Deformities: Genetic Quirks, Not Disease

Meyer Lemon Pest Management: Slugs, Aphids, Leaf Curl, and Organic Fruit Safety

Aphids on Indoor Meyer Lemon: Organic and Chemical Options

Lemon Tree Fruit with Brown Spots: Citrus Disease Identification

Lemon Fruit Small with Dry Dark Indent: Environmental, Not Disease—Need More Info

Meyer Lemon "Tan" Fruit: Environmental Disorder, Not Disease