Common Tomato Problems II

Some tomato problems are caused by pests and diseases rather than weather or soil conditions. In order to grow tomatoes successfully, it’s important to know what the common pests and diseases are and how to successfully prevent them in your tomato garden.

The most common pests and diseases you will likely face as a tomato grower:


Tomato hornworms are common pests attacking garden tomatoes. You will know the worms are there if you notice chewed up leaves and fruits that are unripe but damaged. If you observe these problems, scour your tomatoes to locate the hornworms.

Keep in mind that the worms are very capable of blending into tomato plants. Don’t worry if you don’t notice them straight away and don’t be surprised if you miss them. The worms are big and gray-green in color.

To discourage hornworms, it’s wise to plant some companion plants that are known to deter these pests. Marigolds, opal basil and dill are good companion plants you might wish to try.

Another way to prevent hornworms and to control them is to invite birds to your garden. Put some bird feeders and baths in the garden, as well as some bird houses. However, if you choose this you need to be careful because birds love to eat tomatoes (usually because they are thirsty), so make sure to provide plenty of water for birds. Other animals known to control hornworms are those that eat hornworm eggs: ladybugs, wasps and lacewings. Some people also report that using a hot pepper spray can be effective against hornworms appearing. However, once you spot them you usually need to hand-pick them and remove them from your tomato plants.


Early Blight

Early blight is a fungus that can survive the winter. It can be found on old vines and after the winter is gone it infects the new plants in your garden. Early blight can be recognized as blackish and brownish spots on the leaves or the leaves will start to drop off because you have “sunburned” the fruit.

To prevent this problem, make sure to always clean up old vines at the end of the season. Also, you should rotate your planting areas and space the plants in order to maintain good air circulation to prevent fungi from growing.

Late Blight

Late blight is a problem that manifests as water-soaked patches that will turn brown. They will usually make the surface of the plant look papery and dry. It develops as a result of a fungal activity. This fungus is normally present during the wet weather so the spores can travel long distances and affect a very large area.

To prevent late blight, make sure to rotate crops regularly (each year). Another way to go is to maintain good air circulation around your tomato plants. If you suspect your tomatoes have late blight, remove all the diseased stems, leaves and fruit. Throw them away (not in the garden!) Never put the diseased parts of the plant in your compost pile. In case your tomato plants are severely infected, you might be forced to discard them completely. If this is a prevailing problem in your tomato garden, you may even be forced to discard all of your tomato plants.

Sticky and Deformed Leaves

In case your tomato leaves become shiny, sticky and deformed, it may be a sign of aphids, whiteflies, spired mites or some other pests. Aphids are the most common culprits. They will such the plant sap and excrete a sticky substance right on the leaves and fruit. Aphids congregate on the top growth or undersides of the leaves, but they may be found on other parts of the plant. They are dark, small, pear-shaped insects. Spider mites will produce a number of small yellow specks on the leaves and they will also spin a fine web you will notice on the leaves. The web will also make the leaves feel sticky. Whiteflies will fly when you brush the plant so this is how you can recognize them. If you shake the plant, they will look like dust.

To prevent all these problems, make sure to keep your tomatoes well-weeded. If you notice any of these pests on your plants, make sure to use some effective insecticidal soap to get rid of them.


Nematodes are tiny, microscopic pests that are virtually invisible. They live under the soil and they will cause the root of your plants to swell. The only sign you will be able to observe are discolored leaves.

Nematodes are soil-born and there is no effective cure for them. The good news is that a tomato plant attacked by nematodes will still be able to produce edible fruit. However, once you discover these pests, the only thing you can do is to wait until next year to solve this problem.

The best way to get rid of nematodes is to plant companion plants with your tomatoes. Marigolds are the best companion plants for this situation. They are beautiful and they can kill nematodes effectively. There are also some other companion plants you may try to get rid of nematodes.

Fusarium and Verticillium Wilt

These common problems are caused by an incurable fungal infection. Once your tomato plants develop one of these problems, there is nothing you can do to save them. If these problems occur, you should dispose the effected plants immediately. Make sure to dispose them far away from the garden. Never add the diseased plants to your compost pile!

Fusarium wilt manifests itself on the branches of the infected plants. The fungi will make the branch wilt and become yellow. Verticillium wilt can be recognized by noticeable yellowing between the major veins on the already mature leaves.

The only way to avoid these problems is to choose a hybrid tomato variety known for its resistance against these fungi. Another way to go is to buy your tomato plants from a reliable grower. Usually, these problems appear on plants bought at a large retailer store that’s not specialized in gardening.

Photo credit: DDJClarke via photopin cc