Organic Pesticides for Tomatoes

Tomatoes are easy to grow and great to eat from your summer garden. But certain insects and other creatures enjoy eating them as much as we do, so if your tomatoes begin to show signs of chewed leaves or fruit, plan your own attack. Organic remedies to rid your garden of aphids, hornworms, snails and other destructive pests are available for purchase, or you can make some of them at home. Hand picking the larger pests can be an effective organic method of control.

Bacillus thuringiensis (Bt)

Bacillus thuringiensis, or Bt, is a naturally occurring soil bacterium that kills caterpillars, fruit worms, budworms, pinworms and smaller hornworms. Use it if you have a large infestation of any of these pests. Hornworms are large and ugly. In the larval stage they are called the hawk, hummingbird or sphinx moths. They can decimate not only tomatoes but other plants such as eggplants. They're hard to spot because they turn the color of the greenery they eat, so if you begin to see holes in your green tomatoes, look for small black pellets on the soil and leaves below your plant--these are the worms' droppings. The fruit worm, budworm and pinworm are smaller and cause less damage, but can still be a nuisance. Bt can also be effective in controlling blister beetles, Colorado potato beetles and flea beetles, which sometimes chew holes in tomato leaves. Chemical pesticides are often ineffective against these beetles, so try organic remedies before you resort to poisons.

Insecticidal Soap

Insecticidal soap is a common organic remedy for aphids, leafminers, whiteflies and spider mites. You can buy insecticidal soap at your garden supply store, or make it at home by mixing one tablespoon of a mild dish soap with one quart of water in a spray bottle. Spray your plants thoroughly every other day until you no longer see signs of these insects. Apply insecticidal soap more often in rainy weather.

Beneficial Insects and Birds

Ladybugs are helpful in the garden because they eat aphids, white flies, mites and scale insects. Predatory insects such as the stinkbug, lacewing and parasitic flies will eat some beetles, and some birds are also helpful in controlling these pests. If you allow chickens to forage in your tomato bed, they will peck insects, slugs and snails from the soil.

Hand Picking

Hand picking is another method gardeners can use. When you hand pick, search for the problem insect, pick it off and then dispose of it. Snails and slugs are creatures that gardeners often hand pick. If you stake your tomato plants to support them when fruit begins to form, you'll prevent many snails and slugs from eating the ripening tomatoes.

Diatomaceous Earth and Iron Phosphate Granules

Diatomaceous earth is a natural product that comes from small fossilized aquatic plants. Slugs, snails, sowbugs and other tomato-loving creatures cannot crawl over it. To deter these pests, scatter a thin layer (about one-quarter-inch thick) of diatomaceous earth around the perimeter of your tomato planting area after planting. Repeat the application once a month throughout the growing season. Diatomaceous earth also deters flea beetles, coddling moths, sawflies, twig borers, mites, thrips, cockroaches, ants, earwigs and silverfish.

Keywords: tomato plants pests, organic pesticides, diatomaceous earth

About this Author

Barbara Fahs lives on Hawaii island, where she has created Hiā€˜iaka's Healing Herb Garden. Barbara wrote "Super Simple Guide to Creating Hawaiian Gardens," and has been a professional writer since 1984. She contributes to Big Island Weekly, Ke Ola magazine, and She earned her B.A. at UCSB and her M.A. from San Jose State University.