Growing your own vegetable garden is both gratifying and productive, especially if you grow a variety of tomatoes. And, growing an organic garden is the best way to ensure you grow plants that are delicious and healthy for you and your family. Unfortunately, there are many tomato pests and diseases to contend with during the growing process.
There are a variety of issues that plague vegetable plants, and tomatoes are no exception. These plants deal with everything from fungal diseases and disorders to aphids and hornworms.
Plant disease and pests are a gardener’s worst nightmare, and infected plants cause havoc in the garden if left untreated. While there are some resistant varieties, many heirloom tomatoes are susceptible to disorders.

- Identifying and Treating Tomato Plant Disorders
- Recognizing Tomato Plant Diseases
- Diseases of Tomatoes and Ways to Prevent Them
- Differences Between Tomato Pests and Diseases
- What is Bacterial Wilt, and is it Treatable?
- Preventing and Treating Leaf Mold
- Bacterial Spot and Ways to Prevent it
- What Causes Blossom End Rot?
- Tomato Hornworms and How to Get Rid of Them
- How to Eliminate Aphids on Tomato Plants
- Treating Your Tomato Plants for Whiteflies
- Ways to Get Rid of Cutworms on Tomato Plants
- Eliminating Slugs and Snails on Tomato Plants
Identifying and Treating Tomato Plant Disorders
The simplest of mistakes turn healthy plants into wilting plants that refuse to produce good fruit. Therefore, it’s vital to understand the symptoms and causes to determine the right course of action.
We often think of a plant with wilting leaves and discoloration as a plant in need of water, but this isn’t always the case with tomatoes. There are a variety of tomato problems that must be addressed to ensure you end up with a healthy crop.
A tomato plant in need, whether indoor tomatoes or those in the garden, displays varying signs, and they range from a lack of care to disease and insect infestation. We’ll discuss the different symptoms, causes, and treatments of some of the most common tomato ailments.
Recognizing Tomato Plant Diseases
There are many different tomato plant diseases that you find when you grow cherry tomatoes or beefsteaks, and sometimes it is hard to differentiate between the problems.
Not only that but oftentimes, they do not have a disease but are lacking in proper care. It’s essential to understand what ails your plant to give it the right treatment.
Tomato Plant Disease Signs
While temperature, water, and other weather conditions cause havoc in the garden, there are some tell-tale signs that your plants have a disease. These include shriveling and curling foliage or yellowing tomato leaves.
Tomato leaves with dark brown or black spots, a white film on leaf surfaces, seedlings that tip over shortly after germination, or fruits with mold, soft spots, or rotted ends are also indicators.
If the care you offer your plants is consistent and any of these signs appear, it’s time to take action and treat the disease to save your plant.
Diseases of Tomatoes and Ways to Prevent Them
Discovering your garden is failing feels like the death of your green thumb as you watch your plants wither away, whether it’s from catfacing, pathogens, or insects.
But, don’t let this discourage you. There are many remedies for diseases of tomatoes if you discover them right away.
There is a vast range of diseases that affect garden plants, particularly tomatoes. However, some of them are more common than others.
Fusarium wilt, anthracnose, Alternaria leaf spot, bacterial canker, late blight, and early blight are just a few. Allowing them to run their course leads to unhealthy plants that eventually die.
Fortunately, there are a few simple steps to take to stop disease from ruining your garden. The best thing to do is to use garden or soaker hoses to water your plants in the morning at ground level, and only give them a drink when the top three inches of soil is dry.
Doing this also inhibits concentric rings and tomato cracking. Fungal spores overwinter in the dirt, so make sure to mulch around your plants’ base to cover the spores and limit splashing them onto the leaves.
Provide your plants with a boost of fertilizer during the growing season to provide them with disease resistance.
Clip off infected leaves immediately and dispose of them away from the garden, and disinfect your garden tools after each use to stop the spread of disease.
Prune dense foliage as needed to improve air circulation. Use crop rotation practices to reduce the number of fungal organisms in the ground.
Differences Between Tomato Pests and Diseases
It’s often difficult to know what is wrong with tomato plants when you begin to notice yellow, wilting foliage, and leaf damage, especially if you are new to gardening. Do the plants have an infestation or are they suffering from a disease?
Tomato Pests versus Diseases
It’s hard to determine if your plants are being eaten and destroyed by insects or if they are infected with a disease. One way to figure out the culprit is to inspect the plant’s leaves, stems, and fruits.
If your plants are defoliated, or the seedlings disappear, the enemy is an insect, and insecticides or row covers are required.
Other signs of bugs are partially eaten or holey leaves, slimy trails on stems, and clusters of eggs or larvae near your garden. Plants with brown spots or yellow leaves without insect damage are more than likely suffering from a disease.
What is Bacterial Wilt, and is it Treatable?
Bacterial wilt is one of the common tomato plant diseases, especially if you live in a humid environment and have sandy soil. It often goes unnoticed since the leaves remain green during infection, but it eventually leads to the plant’s death if left untreated.
This disease resides in the soil, and the cause is Ralstonia solanacearum, a pathogen bacterium. While it generally does not cause harm to healthy and strong plants, plants weakened by insects or injury are susceptible.
The bacteria clog the stems and stop water and nutrients from reaching the leaves, eventually killing them. While there is no cure for bacteria wilt, there are ways to stop it from destroying your tomato plants.
If you have sandy soil and live in a humid area, consider rotating your crops regularly or growing them in raised beds. Make sure to space them out evenly for proper air circulation.
Preventing and Treating Leaf Mold
There are many diseases of tomatoes, and leaf mold is a fungal disease that is common in areas with high humidity. If you do not take quick action, your plants’ productivity diminishes, leading to a bad tomato crop.
This common fungal disease is another problem in humid areas. The leaves’ topside begins to develop gray, white, or light green patches of mold, while the underside gets fuzzy and turns purple.
As it progresses, the leaves wither and turn yellow, eventually dying and falling from the plant. The first step to stop leaf mold from getting worse is to air out the plant and avoid watering the leaves.
If the problem is severe, apply a homemade fungicidal spray over the entire plant above the ground. Mix water with apple cider vinegar and spray the fungicide on the leaves in the morning.
Bacterial Spot and Ways to Prevent it
This is one of the most devastating tomato diseases since it spreads quickly and is highly resistant to treatment. Bacterial spot causes leaf spots, sunscald fruit, crop loss, and an infected fruit becomes inedible and requires disposal.
Bacterial spot lives on infected plants and spreads through irrigation and cross-contamination. It is easy to spot by the oily marks or lesions on the underside of leaves.
The dark, green spots turn to purple and then gray, causing the leaves to crack and die. Since the disease affects your crop, it’s important to take care of the problem as soon as possible.
To limit the problem from starting, always purchase certified disease-free tomato seeds and use sterilized potting soil. Practice crop rotation, water your garden in the early morning, and keep the leaves dry while watering.
What Causes Blossom End Rot?
Tomato bottom rot disease affects all fruiting crops, from tomatoes to peppers, and causes severe crop damage. A few main culprits produce this disease, and it’s vital to learn which one is the problem to stop blossom end rot from occurring.
The most apparent sign of blossom end rot is a water-soaked area on the blossom end away from the stem after the tomato fruit is half mature. As the fruit grows, the spot turns brown and leathery as it spreads and rots.
There are a few causes of this disease. These include fluctuations in ground moisture, calcium deficiency in the soil, improper calcium intake, or a wet season that turns dry.
If you reside in a colder climate, wait to plant your tomatoes until after the ground is sufficiently warm. Use a good fertilizer low in nitrogen and high in phosphorus, apply lime to the soil to increase calcium levels, and remove affected fruit as soon as you notice them.
Tomato Hornworms and How to Get Rid of Them
These large, exotic-looking caterpillars love tomato plants, and their favorite part of the plant is the foliage. Where do tomato worms come from? Hornworms are the larvae of the hummingbird moth and leave the plant leafless in a short amount of time, destroying your tomato plants almost overnight.
Hornworms are quite large, reaching up to five inches in length, but they blend in with the color of the foliage, becoming almost invisible at a distance. Heavily chewed or missing leaves are both good signs that there is hornworm activity.
Hand-pick these bugs off your plants as soon as you spot them. Consider planting dill, marigolds, and basil around your tomatoes to deter these pests, and use a natural insecticidal soap to kill them.
How to Eliminate Aphids on Tomato Plants
Aphids are one of the most difficult pests since they are so small and spend most of their time hiding beneath the leaves of your plants. While tomatoes tolerate winged aphids on tomato plants without losing much of their crop, infestation stunts the plants.
If you notice curled or stunted leaves in your garden, check the leaves’ bottom for tiny, yellow-green aphids, and look for honeydew, which is a sticky substance the insects leave as waste.
For the ideal way to use neem oil on tomato plants and kill these pests, use a strong water spray on tomato plants for bugs to dislodge them. Wipe the leaves with a mild solution of soapy water. If this doesn’t do the trick, apply neem oil or flour to the leaves.
Treating Your Tomato Plants for Whiteflies
If you notice a flurry of tiny, white bugs on tomatoes or fluttering out of your garden after you disturb them, you probably have an infestation of whiteflies. It’s essential to identify and treat these insects to deter them from killing off your pants.
Whiteflies have a tiny yellow body and white wings, and their nymphs look like small white pods. They feast by sucking sap from the underside of the leaves, which often leads to sooty mold.
Before planting your tomatoes, spread a layer of silver-colored plastic mulch to repel whiteflies. Weed the garden bed regularly to remove dead material and plant debris and place sticky traps around the bottoms of the plants.
Ways to Get Rid of Cutworms on Tomato Plants
Cutworms are moth larvae that feed on the leaves, stems, and fruit of your tomato plants. They feed during the night and are visible since they curl up in the shape of a C after you disturb them.
Cutworms are most noticeable at dusk when they feed. There are many different species, ranging in color from green and black to gray and pink. When they are not on the move, these worms curl up and are easy to pluck by hand.
To prevent them from destroying your plants, sprinkle crushed eggshells or coffee grounds around the bottom of the plants. Diatomaceous earth is also a good choice for killing these garden pests.
Eliminating Slugs and Snails on Tomato Plants
Another common problem tomato plants deal with are slugs and snails. They damage the fruits by scooping out holes in the flesh and chew through the edges of leaves. Since they are nocturnal, these pests are easy to miss.
Tomato Slugs
While there are many different types, the brown garden slug is the most common pest. They feed on decaying matter and are drawn to your tomato plant leaves and ripening fruits for feasting. The best way to halt them is to keep your garden free of dead leaves and material or tackle slug and snail control with diatomaceous earth sprinkled on the soil around your tomato plants.
Another way to eliminate them is to pluck the snails and slugs off by hand after watering or at dusk. If hand-picking is not your top choice, consider trapping them with boards.
Place a small piece of wood beneath the lower leaves in the evening and scrape the insects off the bottom each morning.
Planting a garden takes a lot of hard work, but the benefits are well worth the effort. Discovering that plant disease or pests such as nematodes and thrips are killing your tomatoes leaves you feeling frustrated and defeated.
Luckily, there are signs to look for, convenient remedies, and ways to stop this from happening to your next tomato harvest.

The key to growing the perfect vegetable garden is to learn about the many tomato pests and diseases that occur during the growing process, so why not share our guide to keeping your tomato plants bug and disease-free with your friends and family on Pinterest and Facebook?