Inch worms are not actually worms; they are the larvae of moths belonging to the Geometridae family. This large family contains more than 1,200 species that make their homes all across North America. The voracious eaters feast on tomatoes, deciduous trees, shrubs, cabbage, potatoes, broccoli, and nearly every other vegetable they encounter. While one or two inch worms in a garden are not cause for alarm, in greater numbers they can obliterate entire crops and kill trees. Whether you're a gardener, a farmer or are simply concerned about the health of your trees, knowing how to get rid of an inch worm infestation can save you endless worries.
Invite the inch worm's natural predators into your yard. Put out bird feeders to attract birds and don't kill the wasps that roam your yard. Plant ground cover plants that encourage beetles to populate your garden. All of these creatures see inch worms as tasty snacks and provide simple, natural pest control.
Protect your trees with sticky tree bands such as BugBarrier or Tanglefoot (See Resources). These barriers wrap around tree trunks to capture female moths as they are climbing into trees to lay eggs. They may also ensnare inch worms that venture out of the tree for food during the day.
Apply bacillus thuringiensis (B.T.) to the infestation site. This bacterium is fatal to caterpillars but does not harm beneficial insects, humans or pets. It works by eating a hole in the inch worm's gut, causing the caterpillar to rot from the inside. It can take several days for the inch worms to die, but once they ingest the poison they generally eat little to nothing.
Bacillus thuringiensis may kill harmless caterpillars and butterflies, so avoid it if you live in or near an area where protected species are found.