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Common Tomato Insects and How to Protect Your Plants

All gardeners are frustrated with tomato pests and the tomato diseases they cause at one point or another. Tomato insects can suck all the joy out of gardening! Occasionally, these pests will invade your garden, attack your tomatoes (and other plants), and you need to know how to deal with them. You can help take some of the sting that tomato plant pests inflict in your garden.

As it is, tomatoes are not the easiest plants to grow and care for through the harvest. In addition to threats from insect pests, various fungi, diseases, and adverse weather may also pose problems for your tomatoes.

Tomato Plant Pests

Tomato Pests

Remember that not every insect pest will cause harm to your garden. Some will actually be good for your plants, some will attack pests that do go after your tomatoes, and others won't affect your tomato plants at all. The most common tomato pests you should watch out for include aphids, cutworms, flea beetles, hornworms, nematodes, and whiteflies.


Aphids (Aphidoidea) are small sap-sucking, pear-shaped insects whose common names include greenfly and blackfly, though individual aphids vary in color. These pests gather on the buds and stems of newly growing plants. Small groups of aphids rarely cause damage to plants, though in larger populations, they can really pose a threat to your tomato plants and other plants in your garden.  

You can manually remove aphids from your plants and the undersides of leaves, or spray them off with water. You can also try planting cilantro, mint, marigolds, garlic, and onions in your garden, as aphids will be repelled away.


Cutworms are a group of species belonging to the moth family Noctuidae. Adults range in color from brown to dark grey to black, and with markings on their front wings. Cutworms are about 3/4" - 1" in length, with an average wingspan of 1-1/2" - 2". Noctuidae species include the common cutworm, turnip moth (Agrotis segetum), the greasy cutworm, black cutworm, and tobacco cutworm (Agrotis ipsilon). 

To help prevent cutworms from chowing down on your tomato plants, be sure to clean your garden thoroughly of the dead plant material left over at the end of each year. You can also try cardboard cylinders around seedlings (cutworms won't climb up and over). 1/2 teaspoon of cornmeal around each plant will help protect your tomatoes, too. Cutworms will eat the cornmeal before getting to the tomato plants, and it will kill them. 

Flea Beetles

What are flea beetles (Alticini)? Imagine the offspring of a flea and a beetle: black flea-like insects that look just like small beetles (about 1/16" in length). These beetles are shiny with long hind legs, and yes, they even jump like fleas when threatened.

Vegetable crops (including tomatoes) are extremely vulnerable to these pests, but flea beetles are also known to feed on other types of plants. They leave their signature "shotholes" in the leaves of plants they feed on. 

Dusting your plants with plain talcum powder repels flea beetles away from tomatoes, peppers, potatoes, and other plants. Catnip and basil also repel them.  

Hornworms (Tomato and Tobacco)

Two garden pest species that can threaten your tomato plants are Tomato hornworms (Manduca quinquemaculata) and Tobacco hornworms (Manduca sexta). Both are typically found in most regions of the United States and Canada. These pests at the larval stage are recognizable by their green color (which helps camouflage them as they move along leaves and foliage). As adults they become grey-ish moths. Hornworms can feed non-stop, leaving behind spotty and chewed leaves and tomatoes. These two types of hornworms also feed on other plants such as eggplants, peppers, and potatoes.  

Handpicking the green caterpillars is effective for controlling these pests on your tomato plants, though this requires time and patience, and probably won't be very effective in a large garden.  These caterpillars are not dangerous and will not sting or bite.   

Tomato Root-Knot Nematodes (Eelworms)

Tomato Root-knot nematodes (Nematoda), also known as eelworms, are tiny worm creatures that reside in the soil and become tomato plant parasites by using tomato roots as areas where they leave their young to grow. Tomato plants are somewhat susceptible to these pests. They are found around the world, mainly in warm, temperate climates. They also feed on peppers, carrots, okra, and several other types of vegetables. The damage caused by these nematodes makes plant grow slowly and in erratic spurts, resulting in smaller plants and tomato yield (as the roots are under attack). 

Yearly crop rotations can help prevent nematode concentration in many cases, but in warm climates and sandy soils, root-knot nematodes are somewhat of a given. Tomato plants are available in various resistant varieties, and soil can be treated with materials containing chitin (e.g., eggshells, seafood meal, etc.). In the ground, these materials feed microorganisms that consume chitin, including nematode eggs.


Whiteflies (Aleyrodidae) are tiny insects with yellow bodies and white wings that feed on the underside of tomato leaves by sucking out the sap. This weakens your tomato plants. Affected leaves begin to turn yellowish-brown and die, while the edges of the leaves curl inward. If whiteflies have a chance to continuously feed from your tomato plants, this will make them vulnerable to mold and other viruses.  

To help prevent whiteflies from destroying your tomatoes: 

  • Inspect the underside of plant leaves before bringing them home. 
  • Weed often to prevent dead plant material from collecting.
  • Use silver plastic mulch (which repels whiteflies) before planting or transplanting.

You can always treat plants with an effective 3-in-1 botanical garden spray that is formulated to treat for insects and fungus, or with insecticidal soap, concentrating on the undersides of the leaves.

What are your best gardening tips and tricks? We want to hear them! Leave us a comment below!  


For scientifically-tested, effective pest control in your garden that is friendly to the environment, try Maggie’s Farm pest control products. Our promise is that our plant and mineral-based products are developed by scientists and seasoned pest control professionals to be the most effective.

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