17 Tomato Plant Diseases and How to Control Them

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The tomato plant is one such vegetable that almost all gardeners try to grow once in their lifetime. This easy-to-grow plant is susceptible to certain pests and infections that can cause problems in your garden. Read on to learn how to treat and manage tomato plant diseases.

To prevent tomato plant diseases, follow some simple steps such as rotating the plant, pinching off the leaves, mulching, providing sufficient air movement, choosing disease-resistant varieties, and companion planting. Management and treatment are possible by using certain fungicides, insecticides, and other chemical treatments.

Tomato belongs to the Solanaceae family. Let’s have a look at the diseases that can affect your tomato produce and how you can get them under control. Each disease will be followed by its prevention and management.

How to Control Common Tomato Plant Diseases

1. Early Blight

Early blight is the most common disease that affects the foliage in tomatoes. Caused by the fungus Alternaria Solani, it causes leaf spots and blight on the older leaves.

If you notice brown lesions on the leaves and concentric rings on your leaves, then your plant is affected by early blight. With high temperatures and high humidity, the leaves get killed.

Management: Spray organic fungicide or copper fungicide once every two weeks to stop the spread of early blight.

2. Late Blight

Unlike Early blight, Late blight occurs in cool and rainy seasons, usually at the end of the growing period. It is one of the most destructive tomato plant diseases. Phytophthora infestans fungus causes late blight. It spreads quite fast through winds.

Management: You can prevent fungal growth by controlling excessive moisture, heat, and overcrowded plants. In case of heavy infestation, throw the infected plant and spray organic fungicide on the rest of the plants.

3. Blossom End Rot

If you notice a leathery, black patch on the bottom side of the leaves, your crop may be affected by blossom end rot. The decay happens due to a lack of calcium. Extreme fluctuation in the climatic conditions can also aggravate the problem of blossom end rot.

Management: Adding calcium levels to the soil helps in dealing with blossom end rot. Avoid using Epsom salt as it contains magnesium and magnesium competes with calcium for uptake. Maintain sufficient moisture by mulching.

Mulching helps in keeping the soil moist and suppressing weeds.

4. Damping-off

Damping-off happens majorly in seedlings and is caused by Pythium aphanidermatum fungi.  It occurs in two stages – pre-emergence and post-emergence.

In the pre-emergence phase, the seedlings die even before reaching the soil surface. In the post-emergence phase, the young seedlings that manage to come up the soil surface die soon after transplanting.

They get soft, water-soaked, and eventually die.

Management: Use raised seedbeds to prevent damping-off. Provide adequate light, well-draining soil, and frequent irrigation.

The disease happens when the seedlings are planted too early in the spring. Start your seeds indoors in a clean potting mix. Avoid using nitrogen-rich soil and allow the soil to dry out in between watering. Apply a fungicide as a preventive measure. 

5. Bacterial Canker

Bacterial canker starts with yellow dots on ripe tomatoes. These yellow spots have dark rims around. It might look like cloudy spot disease but the dark rims help in differentiating.

Management: It is impossible to treat Bacterial canker. Once your plant is infected, remove and throw it away. Avoid planting in the same soil for a period of two to three years. You can prevent it by rotating your crop and clearing out the weeds.

6. Sunscald

Sunscald happens when the tomatoes are exposed to harsh sunlight during hot weather. The plant looks healthy but yellow spots develop on the ripe tomatoes. These cause poor taste.

Management: Make a trellis or system that supports the plants and helps in the proper development of tomatoes along with providing it shade. Try to provide some shade to your plants in harsh summer. Cover the exposed fruits to keep them free from sunscald.

7. Fusarium Wilt

If your plant looks healthy but all of a sudden starts wilting with drooping leaves and stems, it means that it is affected by the fungal infection – Fusarium wilt.

Management: Always plant disease-resistant varieties to prevent such problems. Getting rid of Fusarium wilt is difficult. Disinfecting the stakes using a bleach solution and applying fungicides to the soil helps in dealing with it.

8. Southern Bacterial Wilt

Southern bacterial wilt can cause havoc in your tomato garden if it occurs.

The soil-borne disease spreads unbelievably fast. It is commonly found in places with high temperatures and humidity. If you notice only a few leaves wilting while the rest of the leaves and the plant seems fine, it can be Southern bacterial wilt.

Management: Unfortunately, there is no cure for Southern bacterial wilt. However, you can prevent it by buying only the resistant varieties and growing your plant from your seeds.

9. Septoria Leaf Spot

Septoria leaf spot is a fungal disease that occurs during warm and humid weather when the plant begins to fruit. It begins with blotches on the bottom sides of the leaves on the lower part of the plant. The affected leaves die and fall off.

Management: Remove the infected leaves to control the spread. If the plant is heavily infected, apply an organic or chemical fungicide. The Certis Double Nickel fungicide work well against it.

10. Anthracnose

Anthracnose is a fungal infection that initially looks like circular, sunken, and mushy spots. The spots grow larger over time. Overhead watering and splashing water cause this disease.

Management: To begin with, purchase disease-free seeds as sometimes, fungi are within the seeds. Water your plant in such a way that it goes directly into the soil and does not touch the leaves. Harvest the produce on time as overly ripe tomatoes are more prone to Anthracnose.

11. Verticillium Wilt

Verticillium wilt is a fungal disease that attacks the roots and through the xylem, travels up to the rest of the plant. Initially, the leaves turn yellow and then fall off after browning and withering.

Management: There is not much that helps in treating this disease. You can work on preventing it by crop rotation and using disease-free varieties.

12. Tomato Spotted Wilt

This viral disease is caused by thrips that feed on weeds and ornamental plants. If your tomato plant is nearby such a sight, it can catch this disease. Its signs include the upper foliage twisting and marked with dark spots. The plant’s growth is stunted when infected.

Management: There is no cure for this disease but you can work on its prevention. Reduce the spread of thrips by keeping the grass and weeds mowed. Mulch your garden regularly to keep the weeds and thrips at bay.

13. Yellow Leaf Curl

Tomato yellow leaf curl is caused by whitefly infestation. Its symptoms include the leaves turning upwards with yellow margins, stunted growth, and flower drop.

Management: Remove the infected plant to control whiteflies if the initial symptoms show. Make sure that the soil is well-draining and there is enough air movement. Use whitefly repellents such as canola oil, neem oil. Spray such oils weekly on the affected area.

14. Tomato Leaf Mosaic Virus

Mosaic is a contagious virus and hard to identify. Mosaic appearance on the foliage is a symptom and in severe infection, the leaves look like ferns. It is spread by aphids, whiteflies, and leafhoppers. It can live in the soil for up to two years.

Management: There are no chemical or organic treatments available to treat mosaic. Prevent it by buying only the disease-resistant varieties and removing the infected plant as soon as you notice the infection.

15. Blossom Drop

Blossom drop occurs when the flowers drop before the tomatoes develop. This common problem occurs because of fluctuating temperatures and a lack of pollination.

Management: Always grow varieties that are suitable for your environment.  Pollination is necessary for flower formation. Plant nectar-rich flowers in your garden to attract bees and insects.

16. Catfacing

Deformed tomatoes with rippled blossom end are a sign of catfacing. This physiological disorder leads to malformation and makes the plant prone to fungal infections.

Management: Plant your tomatoes later in the season when it gets warmer. Warm weather helps in the plant’s proper development. Use black plastic spread on the soil to increase the temperature.


Tomato plant diseases are quite common and if you work more on the prevention side, you won’t have to worry about these diseases. If you focus more on preventive measures than curative measures, you will have a healthy produce and lesser problems for future.

We would advise you to use resistant tomato varieties, keep the garden area clean, avoid overhead irrigation, and keep the air circulation high. Keep neem oil handy to prevent mealy bugs, spider mites, etc.

Try to identify the disease and treat it as soon as possible to avoid destroying the entire tomato production. Simple steps like mulching can go a long way in keeping your plant healthy.

We hope our guide has helped you to know all about the diseases and their solutions.