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Excerpt from the Popular Farming Series magabook Organic Farm & Garden with permission from its publisher, BowTie magazines, a division of BowTie Inc. Purchase Organic Farm & Garden here.
Discover these four tomato-plant pests and how you can get rid of them without resorting to pesticides.
1. One of the earliest tomato-plant pests of the season can be one of the most demoralizing for your tomato plants. Cutworms, brownish-gray or green caterpillars, are the larval forms of several different night-flying moths. They hide under the soil by day and emerge at night to chew tomato plants off ground level.
Small-scale gardeners can solve the cutworm problem by wrapping a sheet of newspaper the width of a dollar bill around the stem of each seedling. After wrapping the stem, plant the tomato seedling so that half of the newspaper “cutworm collar” is beneath the soil and half is above. When cutworms forage for tender tomato plants, they’ll find unappetizing newspapers instead.
If wrapping each tomato-plant seedling is too much work, sprinkle diatomaceous earth around the perimeter of each tomato plant. The rough-textured skeletons of tiny sea creatures will deter soft-bodied slugs and cutworms.
2. If brushing into a tomato plant results in a flurry of white flakes, the likely culprit is whiteflies, which suck crucial juices and sap a tomato plant’s vigor. Prevent whiteflies by avoiding high-nitrogen fertilizers, which produce a quick flush of tender foliage. To eliminate them, use yellow sticky traps coated with Tangle-Trap or another gooey material.
3. There’s almost nothing a slug won’t eat, including tomatoes. If you spot neat little scoops taken out of ripe fruit or slime trails across a tomato plant’s leaves, the culprit is likely these, nocturnal, snail-like creatures. A pie tin filled with beer and buried with the rim at ground level will lure slugs to their drunken demise. But beware; beer is such an amazing slug attractor that it should be placed away from the garden. That way you won’t lure the neighbor’s slugs into your lot. Other remedies: hand-picking or surrounding plants with diatomaceous earth.
4. As plants near maturity, they can be attacked by hornworms. These sphinx moth larvae grow to the size of your thumb and can quickly strip a tomato plant of all foliage, even noshing on the unripe fruit. To find them, follow the trails of frass — little, green pellets that used to be your tomato plant’s leaves. Hornworms are easiest to spot in early morning, before they crawl to shadier parts of the tomato plant. Pick the ugly critters by hand and toss them into a pail of soapy water.
If you find a hornworm with rows of what look like rice grains growing out of its back, leave it alone. It has been attacked by a parasitic wasp that will eventually kill the caterpillar and multiply, providing more pest protection next year!
Having trouble identifying your garden pest? Check out the Common Garden Pests slideshow.