Demystifying Tiny Black Spots on Cherry Tomatoes

As gardeners, few things delight us more than harvesting lush, ripe cherry tomatoes straight from the vine. But that joy can quickly turn to dismay when those brilliant red globes are marred by strange black spots. If you’ve noticed tiny black spots marring the skin of your cherry tomatoes, you’re not alone. Many tomato growers encounter this issue. While the spots may look harmless, they can potentially indicate some serious tomato troubles. This guide covers the common causes of black spots on cherry tomatoes and what you can do about them.

What Causes Tiny Black Spots on Cherry Tomatoes?

Several culprits can lead to small black spots on ripe cherry tomato fruits including

• Bacterial canker – Caused by the bacterium Clavibacter michiganensis, this disease leads to small black spots that often have light centers, giving a “bird’s eye” appearance. Very destructive disease.

• Early blight – Fungal disease favored by wet conditions. Causes dark leathery spots on leaves and fruits. Spots on fruits are typically large.

• Blossom end rot – Abiotic disorder caused by calcium deficiency. Leads to sunken black spots on tomato bottoms.

• Physiological flecking – Abiotic disorder causes tiny dark flecks on skin. Worsens with over-fertilization and extreme temperatures. Harmless.

• Insect damage – Feeding by stink bugs leaffooted bugs, and others leads to dark spots where they penetrate fruits.

• Sunscald – Exposure to intense sun can blister fruits, which then form black scabby spots Worst on exposed fruits.

• Environmental factors – Wind, hail, lawn mower damage, etc. can also mechanically damage fruits, allowing decay fungi to create spots.

How to Identify and Treat Black Spot Causes

Accurately diagnosing the cause of black spots allows you to take appropriate action:

Bacterial canker – One of the most destructive tomato diseases. Look for numerous tiny black spots with light gray centers scattered over ripe fruits. Sunken black lesions may also appear on stems.No cure exists. Remove and destroy affected plants immediately to avoid spread. Disinfect any tools used on plants.

Early blight – Irregular dark leathery spots enlarge to form concentric rings. Most severe on leaves but also affects fruits and stems. Use disease-resistant varieties and fungicides. Avoid overhead watering.

Blossom end rot – Sunken black lesion occur on tomato bottoms. Caused by calcium deficiency. Consistent watering can help. Adding calcium supplements may help.

Physiological flecking – Tiny dark speckles on fruits surface. Worsens with over-fertilization and temperature extremes. Harmless and unpreventable. Don’t over-fertilize.

Insect damage – Look for insect pests on plants and fruits. Control them with appropriate organic or conventional insecticides.

Sunscald – Sunken, blistered black spots on exposed fruits. Prevent by avoiding over-pruning plants and providing afternoon shade.

Mechanical damage – Cracks, scrapes, indentations allow decay fungi to create spots. Avoid damaging fruits and stems.

Best Practices to Minimize Black Spots on Tomatoes

While some causes of black spots on cherry tomatoes can’t be prevented, following best practices will minimize many issues:

• Select disease-resistant tomato varieties when possible. Look for resistance to common diseases like early blight.

• Rotate tomato planting beds each year to reduce disease carryover in soil.

• Stake or cage tomato plants and prune selectively to improve air circulation.

• Water at the soil line instead of overhead watering to reduce fungal and bacterial spread.

• Apply mulch around plants to prevent soil splashing onto leaves and fruits.

• Scout plants frequently and remove any diseased or insect-damaged leaves, stems, or fruits.

• fertilize tomatoes based on soil test recommendations to avoid excess fertilizer.

• Use row covers or shading in intense sunlight to prevent sunscald.

• Handle fruits gently to avoid bruising or damaging the delicate skin.

When to Accept and When to Worry

As disheartening as black spots on ripe tomatoes can be, it’s important to accept some imperfection, especially with susceptible heirloom varieties. However, if spots are very numerous, enlarging quickly, or combined with wilting leaves, it likely indicates a disease like bacterial canker that requires swift removal of plants to protect other tomatoes. When in doubt, seeking expert diagnosis from your local extension office can identify if action is needed. Don’t let a few tiny black spots ruin your enjoyment of sweet cherry tomato harvests!