Black Spots On Tomato Leaves – Should You Worry?

Black Spots On Tomato Leaves

Seeing Dark Black Spots appear on your tomato plants can be worrying at first sight. But there are a few things we can do to help you catch this fungi disease in its tracks before it can cause any real harm to your tomato plants.

Below is an explanation of what exactly are these black spots on your tomato plants, how to identify them correctly, and what you can do to help save and prevent your tomato plants from getting them again in the future

 So if you’re noticing black spots growing on your tomato leaves, Don’t worry, we can help you get rid of them!

What is Septoria Leaf spot?

Tomatoes and other members of the Solanaceae family are affected by Septoria leaf spot, which is a disease caused by Septoria lycopersici.

This disease thrives in warm, humid climates and can occur at any time of the year. There are many similarities between this disease and early Bleep.

Septoria leaf spots are darker and more rounded than early blight.

There are many diseases to watch out for, but Septoria leaf spot is an extremely damaging disease to tomato plants if left unaddressed.

It’s important to act immediately to save your harvest after being identified.

Identifying Septoria Leaf Spot On Your Tomatoes

Tomatoes are affected by Septoria and spots appear on older leaves. As they develop, the edges around the spot turn brown as they emerge less than an inch in diameter.

Leaf spots that occur at many points on a leaf are the first signs of Septoria Leaf Spot.

Eventually, these spots will merge into the same place, and as they do, black specks will appear in the center of the plant. These are fungal bodies that produce spores to spread to the rest of the plant.

The spots can be found on stems or even blossoms, but typically stay away from the fruit. It will spread quickly from the lower, older leaves to the younger ones if left unaddressed. The leaves will turn yellow, fall off, and cause a lot of other problems.

Septoria leaf spot thrives in both warm and wet conditions. In these conditions, your plant can be taken over in a matter of weeks if the temperature goes above 80F.

Symptoms of Septoria Leaf Spot on Tomato Plants

Septoria leaf spots begin to appear on the undersides of older leaves at the bottom of the plant. There is a dark brown margin and lighter gray or tan centers on the small ones. The spot may have a yellow halo surrounding it.

The spots may merge together as the disease develops. If you use a magnifying lens, you can see the fruiting bodies of the fungus, which are dark brown.

This is one of the things that distinguishes Septoria leaf spot from other leaf spotting diseases that may occur on tomato plants.

The disease can develop at any stage in the tomato plant’s life, even though the symptoms are usually in the older, lower leaves. They can also be seen on the stems as well as on the blossoms and calyxes.

There is one small bit of good news that rarely affects the fruits.

The black spots may first appear on older leaves. This is usually the case, however, septoria leaf spot can occur at any time in your tomato plant’s life. They can also be seen on the stems as well as on the blossoms and calyxes.

When Septoria leaf spot is not treated, the leaves will turn yellow and eventually fall off. This will weaken the plant, send it into decline, and cause the sun to burn the tomatoes. Tomatoes will not continue to grow unless leaves are present. Septoria leaf spot is spreading quickly.

How It Affects The Health Of Your Tomato Plants

Leaf spot is caused by fungal infections that grow on the leaves. When untreated, these infections can cause the leaves to become wilted, yellow, and eventually fall off. This will weaken the plant, and eventually, the sun will scald the exposed tomatoes.

Leaves provide shade for the plant and keep the sun away from the tomato.  Without leaves, the plant will no longer continue to grow tomatoes.

How Septoria Spreads

Fungi, which are parasites that can cause diseases, spread in the same manner as viruses, by hitchhiking on plants, animals, or other fungi.

The Septoria lycopersici fungus lives in the soil, Septoria lycopersici is a fungus that spreads to the tomatoes and vegetables when they grow. It is spread to the plants through water splashing up on the plants from the soil, insects, people, and equipment.

Best Way to Treat Septoria Leaf Spot


Pruning may not be necessary depending on the tomato plant variety you are growing. However, if you discover septoria on your tomato plant then pruning the leaves early will be the first line of defense. It’s important to remove the leaves that have been infected by the fungus to slow the spread of the disease.

The leaves grow the spores that spread the fungus. The spread of Septoria leaf spot can be stopped if these leaves are removed early. Airflow is an important treatment and preventative measure and Pruning increases it.

Don’t throw these leaves in your compost, as they will continue to grow there. They can be burned or destroyed. This guarantees that the fungus is killed.

Read more: How to Prune Tomato Plants for Optimal Growth

Organic Fungicide Treatments

If you want to treat Septoria leaf spot and other deadly diseases, you should use a pesticide containing copper or potassium bicarbonate. The plants should be sprayed immediately if the symptoms appear.

Ensuring the entire plant is sprayed and covered evenly is done by using a hand sprayer filled with a fungicide solution. On windy and rainy days, do not implement this treatment, as it may spread to other plants in your garden, or run off the leaves and into the soil. If the symptoms don’t disappear after a week, then repeat weekly.

How to Prevent Septoria Leaf Spot on Tomatoes

Garden Hygiene

Good hygiene in the garden will help control the Septoria leaf spot. The spread of Septoria is prevented by this and many other diseases and pests.

There needs to be no plant debris in and around the tomato plants. Weeds, which can be hosts of Septoria fungus, are also included. Once a disease or pest problem has been spotted, always keep your gardening tools clean between uses and always chlorinate them. Crop rotation will help in preventing many diseases, including Septoria Leaf spot, if tomatoes are grown on a large scale.

Read more: 10 Tomato Plant Pests Your Tomato Plants Hate (MUST READ!)

Promote Air Circulation

Tomato plants benefit from adequate air circulation. This helps lower-lying leaves dry out faster and prevents the soil and other areas of the plant from getting too moist.

A properly functioning air circulation system also limits the growth of pests and diseases.

Pruning is also a great way to open up space for airflow in your tomato plants. Pruning off the leaves will give them more room to breathe, and it can also help keep the plant healthy and full.

Adding Mulch To Your Tomato Plants

If you mulch your tomatoes, you prevent them from getting splashed by rainwater and infected soil splashes up on the lower leaves and drips down on the plant’s stem. This keeps the plant clean and keeps weeds from growing beneath the plant.

Mulch is one of those essential ingredients that can make the difference between a great crop and a horrible crop.

Mulch helps regulate water levels, controls weeds, and keeps soil temperatures consistent. If you want to grow tasty tomatoes, get some mulch.

Correct Watering Methods

If you’re not getting the results you want out of your tomato plants, you may need to change things up a bit. Overhead watering leads to water splashing into the leaves, which is great for pests and diseases but not so great for healthy plants.

If you need to re-pot your tomato plant, water only the soil area, not the leaves.

Watering is important for plants, but over-watering can lead to various problems. 

To prevent diseases and damage to leaves, don’t water the foliage as much as possible. It’s also better to water in the morning so that it doesn’t stay overnight and attracts pests and diseases. 

Read more: 5 Signs Of Over Watered Tomato Plants

Plant Next Year’s Tomatoes in A Different Part of Your Garden.

If you’re lucky enough to have a big enough plot to grow more than one crop per year, it may make sense to grow them in rotation. This gives your plants a break and ensures that your crops receive the best possible conditions during their growth cycle.

In conclusion, septoria leaf spot is a common problem for tomato growers. However, there are several ways to deal with it, including using fungicides, resistant varieties, and cultural practices. By using one or more of these methods, growers can keep their tomatoes healthy and productive.

Frequently Asked Questions About Black Spots (Septoria Leaf Spot) on Your Tomato Plants

What Is the Best Fungicide for Septoria Leaf Spot?

In order to prevent Septoria leaf spot, use fungicides with active ingredients like chlorothalonil, copper, or mancozeb to help reduce the disease. However, they must be applied before symptoms appear as they cannot cure the plant…

Should I Cut off Leaves with Black Spots?

Yes. Remove any Blackend, dead or dying leaves on your tomato plants. If these leaves are more than 50% damaged, cut them off to allow the rest of the healthy foliage to receive more nutrients and improve its appearance.

Will Cut Leaves Grow Back?

Yes, tomato plants will typically regrow leaves that have been cut off. However, it is important to cut the leaves off cleanly and avoid damaging the plant’s stem.