Like tomatoes (Lycopersicon esculentum) themselves, tomato worms come in a wide array of colors and sizes. What they share is a voracious appetite for tomato plants’ stems, fruit or leaves. Using chemical-free methods to dispense with these creeping eating machines has significant benefits. It shields the honeybees and other beneficial insects in your lawn and ensures you a safe-to-eat tomato crop. In addition, it encourages hands on familiarity with your crops, and also the ability to spot and resolve problems quickly.
Fulfill the Enemies
Tomato or tobacco hornworms reach 3 to 4 inches long before pupating. These leaf- and also stem-feeding caterpillars are pale-green with dark diagonal stripes or V-shaped markings, and single, slender horns protruding from their tail ends. Much smaller light-green loopers also consume foliage, but they arch their backs as they move ahead. Gray to yellowish pinworms, bristly black-headed fruitworms and green-and-white or black-and-yellow armyworms devour leaves and fruit. Cutworms chew through youthful tomato stems or, later in the year, nibble shallow holes in the fruit.
The best way to keep worms away from your tomatoes without substances is to safeguard the plants with floating row covers, also called garden fleece. The elastic, transparent, porous covers allow light, water and air to attain your tomatoes while maintaining egg-laying moths away. They work on all however trellised plants. Because self-pollinators, tomatoes don’t need bees to assist them fruit, so floating row covers won’t interfere with your own harvest. To use them, insert cable row-cover hoops — similar to giant croquet wickets and offered in different heights — to the ground in the manufacturer’s recommended spacing. Drape the row covers over them and pull them taut. Secure them into the hoops with clothespins, spread the excess material over the ground and then weigh it down with dirt.
The After-Dark Approach
Early in the growing season, head to your tomato patch nicely after dark with a head-mounted torch, gloves and a sealable plastic garbage bag. Use one hand to search the leaves and branches for worms and another to handpick and toss them to your bag. In case a sunrise raid works better for you, search dew-moistened or damaged leaves first. The worms may not have retreated to their day lairs.
Wasps vs. Worms
You may not keep moth eggs from the tomatoes, but commercially accessible Trichogramma wasps may keep the eggs from hatching. Every single pinhead-sized wasp deposits a single egg in each egg of its target moth species. Within 10 days, the developing wasp larva has consumed the developing worm and also exited the blackened egg as an adult. The commercially available wasps are offered as parasitized moth eggs attached to paper cards. A single card contains tens of thousands of eggs, each sheltering an about-to-emerge wasp.
Releasing the Wasps
Monitor your tomatoes daily, and release the wasps as soon as you see moths around them. On a calm early morning or evening with a fever between 80 and 90 degrees Fahrenheit, hang the maker’s recommended number of cards from the tops on your own tomato cages or out of stakes set one of your plants. Keep them from direct sun and avoid touching the eggs. Leave the cards for at least a week so each of the wasps have enough time to emerge. Release fresh wasps weekly until the moths have been eliminated.