Pests & Diseases In Tomatoes; All You Need To Know

Pests & diseases - Pic of a healthy tomato

Pests & diseases – Pic of a healthy tomato

If you farm tomatoes, there are things that you need to be on the lookout for so as to have a successful harvest. Because farming is challenging, one should be very keen and vigilant at all times. One of the major challenges that a tomato farmer may face is pests & diseases. If not prevented or detected early enough, they can cause a lot of damage, resulting in great losses.

To produce that perfect tomato, be alert. Keep an eye on your plant’s health, look for larvae and other insects, and watch out for signs of disease.

Let’s dive right in. Here is a list of some of the pests & diseases that affect tomatoes:


  1. Blossom End Rot

The plants appear healthy, but as the tomatoes ripen, an ugly black patch appears on the bottom. The black spots on tomatoes look leathery. When you try to cut off the patch to eat the tomato, the fruit inside looks mealy.

This is because your plants aren’t getting enough calcium. There’s either not enough calcium in the soil, or the pH is too low for the plant to absorb the calcium available. Uneven watering habits also contribute to this problem.

  1. Mosaic Virus

The mosaic virus doesn’t kill the plant, but it diminishes the number and quality of fruits. You will notice markings that resemble a mosaic of light green and yellow on the leaves. Leaves may also grow in misshapen forms, resembling ferns.

Because the virus must enter through a cut in the plant, avoid handling the plant. Anyone who uses tobacco can transmit the disease. Wash hands with soap to cut the risk of infection.

  1. Late Blight

Late blight occurs during periods of cool, rainy weather that may come at the end of a growing season. It looks almost like frost damage on leaves, causing irregular green-black splotches. Fruits may have large, irregular-shaped brown blotches that quickly become rotten.

  1. Bacterial Wilt

Young leaves wilt in hot weather, despite adequate soil moisture. The plant remains green but wilts and dies.

To confirm infection, cut the stem at the base of the plant and suspend in water. If bacterial wilt is present, a white slimy substance will be present. There is no cure. Lift and destroy immediately.

  1. Anthracnose

As tomatoes ripen, a dark, bulls-eye circle appears on the bottom of the tomato. The spot is sunken and mushy to the touch. When you slice into the tomato, there’s a black mushy spot underneath that looks like rot.The fungus loves hot, moist weather.

  1. Early Blight

You’ll find brown spots on tomato leaves, starting with the older ones. Each spot starts to develop rings, like a target. Leaves turn yellow around the brown spots, then the entire leaf turns brown and falls off. In the end, the plant may have few, if any, leaves.

  1. Septoria Leaf Spot

After the plants begin to develop tomatoes, the lower leaves break out in yellow spots. Within the yellow spots, dark gray centers with dark borders appear. Black dots appear in the center of the spots. Foliage dies and falls off.

  1. Fusarium Wilt

Your tomato plants look fine, then they start to wilt. It may affect only one side at first, but then the whole plant wilts. You water them, and the problem gets worse. Consequently, the plant dies within a day or two.

The fungus causing this destroys the xylem tubes, which transport water and nutrients up from the roots and into the leaves.

Related Post: 8 Ways To Prevent Pests & Diseases in Tomatoes

  1. Verticillium Wilt

Yellow blotches appear on the lower leaves. As the blotches spread, the veins in the leaves turn brown. After the leaves turn brown, they fall off. Stunting occurs once the disease progresses up the stem.

It is caused by a fungus that lives in the soil attacks the roots and travels up the xylem tubes with water. It then prevents the normal flow of water and nutrients to the leaves.

  1. Powdery Mildew

Powdery mildew is easy to find on tomato plants as it looks like someone brushed the leaves with a white powder. You might find white spots on tomato leaves or even the stem. If you let the fungi thrive it will turn your tomato leaves yellow and then brown.

It is more common in greenhouses than in open fields because of the lack of airflow and high humidity.


  1. Aphids

Clusters of small sap-sucking insects, usually under leaves. Will reduce plant vigor and can spread plant diseases.

  1. Whitefly

Tiny white-winged sap-sucking insects that congregate on the undersides of leaves, reducing plant vigor. Adults fly from plants when disturbed but quickly resettle.

  1. Caterpillars

These enter fruit at a young stage. Fruit continues to grow with the caterpillar developing inside. Rot occurs as the fruit ripens.

  1. Fruit fly

White maggots found in ripening fruit causing fruit to spoil and rot.


In addition to pests & diseases, one final tomato problem that is probably always mistaken for insect damage is birds. Some birds like crows love to eat ripening fruits.

The best control for bird problems is a net. Drape a large shade net over the plants. The net is an effective deterrent to birds and usually a good deterrent for squirrels, too. Using a scarecrow can also assist in controlling the birds.


In conclusion, although this list of pests & diseases is extensive, don’t let it deter you from growing great tomatoes. Once you take precautions, your tomatoes will continue to be fruitful and successful.





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