Five of the Buggiest Foes of Tomatoes – Harmful Insects


These tiny sapsuckers are headaches for all gardeners, especially in large numbers. In fact, those harmful insects are often considered the most destructive pest in temperate climates. That said, I do believe they have one of the cutest little bug faces. Those cute faces are very stabby, though. Using piercing mouthparts, aphids wound leaves and feed on the plant’s nutrients. Luckily, their bodies are so small they can’t do too much damage in small numbers. Small populations can easily be wiped from leaves. Larger populations may need a bit more attention, though, such as pruning or blasting plants with water.

Colorado potato beetle

Found throughout much of North America, these recognizable striped adversaries are known to stunt plants when present in large numbers. Like many pests, they’re not just fond of tomatoes; vegetable gardens containing peppers, eggplants, and potatoes are often the victims of these beetles. Handpicking and “disposal” of these crawlers is often effective control. If you have an infestation, avoid planting their favorites (the nightshade family) in the same spot the following season. Those harmful insects overwinter in the soil and will happily emerge to begin feeding again once it warms!


These soil-dwelling moth caterpillars are kind of like tiny, ax-wielding lumberjacks. The most obvious damage from these little buggers is the path of destruction they leave behind: tomato seedlings cut down right at the stem—sometimes entire crops of them. These cutworms can also attack older plants at the stems and leaves, weakening the plants. Prevention is your best chance against these night-creeping pests. Creating cardboard collars can protect young plants. Cornmeal spread around the plants is also reportedly effective at killing them. If you want to handpick them, use a flashlight because they’re active only at night. A quick tip: They overwinter in dead plant material, so be sure to clear debris to help reduce future infestations.

Harmful Insects - Five of the Buggiest Foes of Tomatoes


Possibly the most notorious “tomato bug,” hornworms are despised by many gardeners. These moth caterpillars are common in not only North America but also in Australia. They are mean, green, nonstop-eating machines (though they’re really not that mean). While they can cause lots of damage, especially in later stages, these squishy bugs can easily be managed, but it requires vigilance on your part to pick them. These are also very cool bugs to demonstrate metamorphosis with. So if you don’t mind a few chewed leaves here and there, it’s nice to keep a couple around to witness their transformation yourself or to share it with some nearby kiddos.

Spider mites

Often most prevalent in greenhouses or indoors, these little eight-legged creatures can also be found in great numbers in dryer areas. Much like aphids, they pierce plant tissue and steal nutrients from the plants. If you’re wondering how to know if spider mites are present, think of tiny yellow dots appearing on leaves and fruits and telltale webs. Though not overly concerning in small numbers, spider mite populations that grow out of control can decimate a tomato plant. Dispose of infested material to reduce the risk of spreading the infestation further. If populations are uncontrollable, there are many biological controls available but know that these are most effective in greenhouse situations.

Lauren Davidson

World Tomato Society Entomology Expert

Readers Comments

2 responses to “Five of the Buggiest Foes of Tomatoes”

  1. TomatoWomaniac says:

    FYI, Hornworms glow in the dark under a blacklight and you can knock them out for good with one dedicated after dark rave party!

  2. says:

    Any suggestions as far as beneficials are concerned in a greenhouse? My main problem insects are spider mites, thrips and Mormon crickets (if they can get in). Our growing season is 90 days with luck, usually less than that, so the greenhouse is the place.

Leave a Reply

Your email address will not be published. Required fields are marked *