Growing Your Best Tomatoes Yet: Pests and Diseases

Tomatoes are a beloved crop for many gardeners, prized for their fruit that can be used in a wide range of dishes. However, nothing is more frustrating than when your tomato plants fall victim to pests or diseases that can cause damage or even death. In this article, we will discuss some common tomato pests and diseases and provide tips for preventing and controlling them. By taking proactive measures to reduce these annoying and destructive issues, you can enjoy a healthy plant, and harvest!

The tomato hornworm is a large, green caterpillar that feeds on the foliage and fruit of tomato plants. They can grow up to 4 inches long and can quickly strip a plant of its leaves. One of the most noticeable signs of a hornworm infestation is the presence of large, black droppings on the leaves and ground around the plant. You may also notice holes in the leaves or partially eaten fruit.

You can handpick them off the plant or use an insecticide containing Bacillus thuringiensis (Bt), a natural bacteria that targets hornworms and other caterpillars. Bt can be sprayed on the plant and is safe for humans and most beneficial insects. These control methods also apply to tomato fruitworms, a common fruit and crop pest.

Aphids

Aphids are small, soft-bodied insects that feed on the sap of tomato plants. They can cause the leaves to curl and yellow, and they can also transmit viruses. They reproduce quickly and can quickly build up large populations if left unchecked.

To control aphids on tomato plants, you can use a strong stream of water to dislodge them from the leaves. This can be done by spraying the plant with a hose or using a spray bottle filled with water. You can also use insecticidal soap, neem oil, or a solution of water and dish soap to kill aphids on contact. Another option is to use natural predators of aphids, such as ladybugs or lacewings, to your garden.

Early Blight

Early blight is a fungal disease that causes brown spots on the leaves and stems of tomato plants. These spots can grow larger over time and eventually turn yellow and dry out, causing the leaves to die. The disease can also infect the fruit of the plant, causing it to develop dark, sunken spots that can lead to rot and mold.

It is important to practice good sanitation practices when early blight is a threat, such as removing and disposing of infected plant debris to prevent the disease from spreading. You can also use a fungicide containing copper or sulfur to treat the plant and prevent the disease from spreading.

Late Blight

Late blight is a fungal disease that can rapidly kill tomato plants. It causes brown spots on the leaves, stems, and fruit of the plant. If the disease is caught early enough, you may be able to save some of your tomato plants by removing the affected leaves and spraying with a fungicide. However, if the disease has already spread extensively, it may be too late to save the plants and you may need to remove them entirely to prevent the disease from spreading to other plants in the area.

Blossom End Rot

Blossom end rot is a disorder that causes the bottom of the tomato fruit to turn black and rot. It is caused by a calcium deficiency in the plant or irregular watering. To control blossom end rot, you can provide consistent watering and add calcium to the soil through amendments or fertilizers; a common solution among gardeners is adding crushed eggshells or bonemeal to your soil.

Once a fruit has been affected by blossom end rot, it’s best to remove the infected fruit. Though the disease is not transmittable, blackened fruits cannot recover from the damage.

Fusarium and Verticillium Wilt

Fusarium and Verticillium wilt are fungal diseases that cause leaves to yellow and wilt. The wilting starts from the bottom of the plant and works its way up quite quickly until the whole plant is dead. It can also cause the plant to die prematurely. These types of bacterial wilt have a distinct "burning leaves" look to them, as opposed to the dotted infected areas blight carries.

The fungus can survive in the soil for several years, making it difficult to control once it becomes established. To prevent and manage fusarium and verticillium wilt, you can rotate your tomato plants with other crops to prevent the buildup of the fungus in the soil. With a disease as difficult to manage as fungus wilt, in severe cases fungicides may be necessary to control the spread of the disease.

Although tomatoes are sensitive and susceptible to different ailments, there are certain varieties that are resistant to some common diseases. When selecting disease-resistant tomato varieties, it's important to look for specific letters that indicate the type of resistance. The most common letter used to indicate resistance types are as follows: V indicates resistance to verticillium wilt, F indicates resistance to fusarium wilt, EB and LB indicate resistance to early and late blight.

In addition to these pests and diseases, there are many other potential problems that can affect tomato plants. To minimize the risk of damage, it is important to provide the plant with adequate sunlight, water, and nutrients, and to monitor it regularly for signs of pests or diseases. When problems do arise, prompt action can help minimize the damage and protect the health of the plant.