Worm pests in the garden cover a range of species that can create large amounts of damage. Although they go by many names such as armyworm, cutworm, and tomato worm, they’re actually caterpillars that will soon turn into moths and butterflies. In this larval stage, though, they are voracious and on the attack among your favorite vegetables and flowers.
Many worm pests are leaf-eaters, while others feed on the stems of young shoots, consume buds or dive into fruits. You may first notice a few irregularly shaped holes in leaves or young plants that have weakened and fallen over. As the larvae continue to feed and grow, they may be visible, but if nocturnal, you may miss their physical presence.
It’s important to identify which worm pests you’re dealing with and that will vary by region. The worms are exceedingly picky about what they’ll eat, so sometimes you can isolate plants to keep from spreading the damage. This may not be possible, however, in smaller gardens and yards. Keep in mind, too, that a few caterpillars won’t cause a great deal of harm, especially if you “give” them a section of your garden for feeding. Unfortunately, populations can become out of control and all your nurturing and hard work is at risk.
When you want to take a non-chemical approach, try handpicking the worms off the plants. For those night-feeders, use a flashlight. You probably won’t get them all, but it’s one of the best “green” ways to control damage. Also, dig through the debris at the bases of plants as that’s where some worms will return after a day of feeding.
Bt, or Bacillus thuringiensis, is one of the best non-toxic treatments. The bacterium occurs naturally in the soil and is available as an insecticide. This organic is also recommended as it won’t harm beneficial insects, including those that prey on caterpillars. It’s easy to apply – just spray on leaf undersides. When consumed, it causes a digestive paralysis. The worms may not perish right away, but they will be unable to eat.
Neem oil is another non-toxic alternative to chemical controls. It’s harvested from the Azadiracta indica juss (neem) tree of India origin and is available in concentrate or ready-to-spray form. It is also applied to leaves, especially the undersides, and works as both a repellent and appetite suppressant. Neem is proven to work on a host of other garden ills including fungus and aphids and is recommended for indoor plants as well. Both Bt and Neem are approved for edible vegetation.
Caterpillars such as cutworms that feed at the bases of plants require barrier tactics. When seedlings are just beginning to sprout, surround them with wax-coated paper cups. Cut a hole in the bottom and sink the collar about an inch into the ground. This will keep the worms away and they won’t be able to dislodge the cup base.
You can also incorporate more potent chemical protection. Products that contain pyrethrins or carbaryl, including Sevin dust, will protect plants. Always follow instructions carefully for treating worm pests in gardens with any toxic product.