Tomato plants turning black is one of the most common problems of your plants, but not without a cure. Tomatoes are one of the easiest fruits to grow. However, those black spots can cause us to freak out.
In this article, we will be dealing with the most common causes of tomato plants going black and how to deal with them properly, as most diseases will cause your plants to go black, so let’s see what they are.
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- What Causes of Tomato Plants Turning Black
- What Are Ways To Prevent The Tomato Plants from Going Black?
What Causes of Tomato Plants Turning Black
The causes of tomato plants turning black are septoria leaf spots, anthracnose, wilting diseases, early or even late blight. In addition, it could be due to tobacco mosaic virus, blossom rot, damping off, or lastly, due to sunscale the vegetables would look darker as they burn their skin.
The tomato plant is a garden favorite! This is a tender perennial grown as an annual in temperate climates. Tomatoes are easy and prolific growers with a thousand cultivars and varieties.
Tomatoes are vigorous growers that will produce fruits barely by standing in the sun! However, they aren’t without their weaknesses — tomato is one of the most disease-prone plants in the entire world, and will almost inevitably get some diseases along the way.
– Septoria Leaf Spot
This one is a common garden disease and is well-known among the tomato-growing community. This is a fungal disease commonly spread by water and moisture droplets. The fungus causing this disease is called Septoria Lycopersici and is attacking tomatoes at any stage of their development.
Although it is the most widespread fungi in the garden, it’s not the deadliest and is curable. Any Solanaceae plant can get infected by this one including potatoes, eggplants, and tomatoes. This plant disease will first appear as small black dots on your tomato leaves, not much different from other damages made by insects or other diseases.
As it matures, the lesions will begin to spread as you water the plant, and will grow to almost an entire leaf size. It will be gray in the center and yellow and black on the edges, and slowly but surely the disease would take over the fruit and cause it to become darker in color. Ultimately, the lesions will form black-dotted spores ready to be spread to other plants.
Anthracnose is another fungal disease caused by a pathogen called Sphaceloma or Colletotrichum. This one is causing a somewhat more serious condition than other fungal diseases, and you should be alarmed because this would spread as the moisture has been enhanced around it.
This disease first appears as white or yellow spots on leaves and then it takes over the fruit; eventually, the rings will surround the initial spots. Leaves will go black and eventually fall off, and this would be a common sign for you to notice the fungus.
The thing with anthracnose is that it attacks the main supply veins of your plants and will be affecting the fruit as well — the fruits will go completely rotten if you leave them on the plant for long periods, so you should be mindful to pick them as soon as they mature. In short, note that this disease, specifically, is likely to develop during the warm and moist periods of the year, which is summer, coincidentally when the fruits begin to develop.
– Wilting Diseases
Two other fungal issues that cause black leaves on this list. However, wilt won’t come from above but from below — the pathogens are lurking in the very soil. Fusarium and Verticillium are two species of fungus causing wilting in plants.
Fusarium wilt and verticillium wilts will enter into the plants via roots. As soon as they enter plant organisms, they will disrupt the water and nutrients flow in the plant causing wilt, dieback, and even vascular stains — these attack the thin vessels that would transport them.
You can never be sure which wilt is attacking your tomato plants, as both will have the same symptoms. However, if your plants appear to be curling and wilting and suddenly get better in the evening, then wilting again in the morning you’re probably dealing with wilt.
The best way to control these would be to buy species that are specially bred to be resistant to wilts. These will be labeled as V or F for verticillium and fusarium variations respectively, and you will easily know that they are significant for them.
– Early or Late Blight
Alternaria Solani is another fungus-causing bacterial canker or early blight disease. Being a tomato and potato-specific disease, this one strikes when your tomatoes begin to develop fruits. Foliar or leaf symptoms of blight are black and brown necrosis.
At first, these symptoms are only visible on lower leaves and are very hard to spot before they spread to the entire plant. The disease begins as a dark brown blotch just a few millimeters wide, and slowly begins to spread across the entire leaf. Once the whole leaf becomes necrotic, it will dry up, die, and look totally black.
Just like any other fungus, Alternaria stem canker will spread by rain and will evaporate to the lowest leaves from the ground. As a result, it is very important that you inspect your plants often and pluck and cut the infected leaves before the blight tackles the entire plant.
Moreover, you must also consider late blight, as if the early setting blight attacking your fruits wasn’t enough, you’ll have this disease to deal with during the rainy and cold seasons. This one is caused by the fungus Phytophthora infestans.
Much like the previous disease, this one will cause black and dark-green blotches that will spread in the cold and rainy weather of early fall; however, at first, the necrosis is small until it spreads and ruins entire leaves and the plant.
You likely won’t be worrying about this one as it will attack tomatoes when they aren’t producing fruit. However, late blight may cause worry about gardeners in warmer climates, growing these red berries as perennial plants.
– Tobacco Mosaic Virus
Also known as the ringspot virus, this one is the most common type of plant virus. This one emerges as yellow and dark spots on tomato leaves and is a disease taking mostly plants from the tomato and squash families.
Aphids and fresh cuts are the most common issues that cause the appearance of the virus, so you should always work with a clean set of disinfected gardening tools. You’ll recognize this virus by black and yellow spots that will soon spread and make your tomato plant leaves turning black, and appear curled and fern-like.
This tomato plant disease also causes a syndrome known as shoestring syndrome, making the leaves edges curl up, and your leaves appear tight and narrow like shoe strings. After doing so, the veins would become more compact and the fruit will be damaged, it wouldn’t have enough nutrients coming, so the color will fade.
– Blossom Drop
Blossom drop is a heat wave-related disease appearing when temperatures go above the 85-degree Fahrenheit mark. This disease is particularly malevolent because it directly attacks the blossoms in their development stage.
Sometimes you won’t even notice that something is wrong until you begin to see that there are fewer fruits than expected. Tomato blossoms often develop yellowing pedicel around them, soon after the leaves turn black and ultimately fall to the ground. You’ll likely think that this one is caused by the weather, when it’s a fungal disease too, caused by Monilinia Iaxa and Fructigena pathogens.
– Blossom Rot
Rotting of the flower is also known as blossom-end rot, and this is caused by a lack of nutrients available to your plants or even by a fluctuating watering regime and availability. It’s a common blackening problem impacting tomato fruits.
You won’t likely be noticing it at all before it strikes your tomato fruits, but thankfully it will appear at the early stages of fruit ripening. It begins as a small, depressed dent at the bottom of the fruit, hence the name, which will enlarge as the fruit grows, sometimes reaching an entire half of the fruit size.
The end lesion will be hard, black, and leathery in structure. To fight this one, a bit of good advice is to mulch your soil properly and avoid exposing your tomatoes to prolonged periods of droughts.
– Damping Off
Damping off is a frustrating fungal disease, often striking young tomato seedlings. It is caused by a string of fungi species, most prominently Pythium, Rhizoctonia, and Phytophthora. Tomato seedlings are mostly attacked when the conditions are wet and humid, especially if you leave moist soil in a cold environment.
If your tomatoes succumb to this blackening disease, they most likely won’t make it out of it alive. Seedlings will often appear fine, healthy, and vigorous just to collapse and die shortly thereafter.
When this happens, you will begin to spot this disease only when at the terminal stage by a spongy and wilted stem just at the place where it enters the soil. It is at this point that the stem won’t be able to hold the plant straight any longer, and the plant will collapse.
Sunscald is damage made by direct exposure to sunlight, and the name is upon it. Sun can burn and make your plants black, dry them out, and even potentially kill them! If you’re keeping a careful watch on your tomatoes and you’re sure nothing else would hurt them, the sun is your most likely enemy.
The harshness of the rays can even burn and dry the fruits while they’re still hanging on the plant, so you’d want to make sure enough foliage is on the plant to provide shade for the developing fruits.
What Are Ways To Prevent The Tomato Plants from Going Black?
Ways to prevent the tomato plants from going black are to spray some fungicides, use organic fungicides, or buy the seeds from a reputable source. In addition, you should also choose well-draining soil to decrease the moisture, and water it only when the soil is dry.
– Spray Some Fungicides
A sort of fungal disease will directly cause most spots on your plants. It’s therefore, essential to treat your tomatoes with fungicides readily available at your garden centers just as you replant your plants in spring. These fungicides will largely be aggressive, so try to go for a more natural commercial solution to get rid of these tomato diseases.
– Use Organic Fungicides
If you’d like to prep your fungicide at home, good options are always baking soda, neem, or horticultural oils! Just mix any of these in a larger amount of water and spray your plants regularly throughout the growing season. Neem oil for tomatoes is highly recommended!
These and fungicides that you can easily use as they have organic properties and they will tackle pests away, as well as some diseases to help your fruit stay red.
– Buy From a Reputable Source
Fungal tomato plant diseases are so hard to avoid when you’re growing tomatoes, but one thing you can do is fight this with genetics! You can opt to buy tomato species specifically bred to be fungus resistant.
When buying small samplings of tomatoes guide yourself by markings on the label; this will help you in the long run, because now you have the awareness that the fruit will not sprout infected, or genetically have any form of the disease.
– Choose a Well-draining Soil
You should also be mindful of the environment in which you plant your seedlings. This means that you must choose soil that’s not all clay in order to reach a successful drainage and ensure your roots get the air they need, and this way, fungi or any disease that may cause infestation will not tackle the plant.
Fungi love stale and moist conditions, so providing airflow above the ground is necessary too; this is their favorite environment or medium to thrive. You should also try to aerate the soil, gently, like a summer breeze, because it is always helpful, but you should look to space out your plants a few feet away from each other, if possible.
– Water When The Soil Feels Dry
Watering is another important part of preventing fungal diseases in tomato plants. Your tomatoes love a drink of water, but if it’s the rainy season you may want to turn the water off; make sure that you do not water it again after it has rained. A good rule to guide yourself by is to water the plants only when the soil goes dry as you touch it with your finger.
Tomatoes are a garden favorite, and are vigorous growers, but not without their set of ailments — most of these causing those nasty spots. So, let’s go through the most important part that we’ve covered:
- If you spot black leaves, you’re likely dealing with either a fungal disease or an elemental problem. What you want to do is approach your tomatoes with more care and study the issue for a few days.
- If you’re dealing with any type of fungal disease, the dark spots will change color and spread almost in a regular pattern. Sun and cold damage, on the other hand, will have a more instant effect!
- To treat your plants, always remove damaged parts and turn up your fungicide spraying regime. To prevent fungal diseases from affecting your plants and fruits, go with seedlings that were bred to resist diseases.
Botanically, this plant is a fruit, more precisely a berry that vines in erect and ascending stems covered with dense and sticky hairs. Its leaves are compound, growing in an alternating pattern, and around 10 inches long with serrated margins. We have it all covered when it comes to black and browned plants, and we’re sure you’ll deal with these issues much better now.