Maine Organic Farmers and Gardeners Association
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Scrutinize Plants for Hornworms

Hornworm damage on ripe tomatoes

Hornworm damage on ripe tomatoes

August 24, 2017

Hornworms are probably the most destructive insect on tomatoes, says MOFGA's organic crop specialist, Eric Sideman, in his article "Enjoy the Garden: Minimize Summertime Blues."These giant caterpillars can eat a vast amount very quickly, sometimes almost stripping a healthy looking tomato or pepper plant of its foliage overnight, leaving only bare stems. Hornworms also attack fruit, chewing gouges so large that they look more like bites of a furry animal rather than an insect. Watch for hornworm damage and frass (excrement) – black pellets lying around hornworm host plants. Frass may be the first sign of a problem. Scrutinize your plants, because these green caterpillars are difficult to see against green plant tissue, and one or two caterpillars can do significant damage in a day or two. Pick hornworms off plants by hand. Bt also helps control this pest.

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