Want to know what's been feeding on your plants? Every pest leaves telltale signs and once you recognize them, you’ll have a pretty good idea who is the culprit.
Rabbits and Deer
Rabbits prefer to feed on new, tender growth, including stems, growing tips and leaves, leaving behind neatly clipped plants. Sometimes they'll chew on an older leaf but won’t eat the whole thing. Rabbit damage is usually low to the ground. They also knaw the bark on woody plants, especially in fall and winter. Such damage can be deadly for plants.
A vet will tell you that deer lack upper incisors, so they bite foliage and tear it free, creating jagged edges on stems and broken branches. You should also notice hoof prints in soft soil and lawns if deer have been around.
Deer or rabbit repellants can sometimes deter these animals. The only sure-fire control is a physical barrier, such as a properly designed fence, or getting a dog.
Snails and Slugs
These slimy monsters like to hang out where it's shady and moist. They'll also attack plants growing in full sun, as long there's a place to hide out during the day, like under rocks, landscape timbers, pots or mulch. When Slugs and Snails feed, they usually create irregular-shaped holes in the leaf, not along the edges. This often differentiates them from many other insects that start feeding from the outside of a leaf and work their way in. However, the surest way to identify Slugs and Snails is to look for slime trails or walk the garden after dark with a flashlight. Look on the ground and on leaves, top and bottom.
Caterpillars and Worms
Caterpillars are the larvae of moths or butterflies. Some look more like smooth-skinned worms than the hairy beasts we usually think of as caterpillars. They eat irregular holes in leaves, often feeding on both older and new growth. Some types, known as Cutworms, chew through seedling stems at soil level, causing them to fall over like timbers. Many Caterpillars, including the voracious Tomato Hornworm, boast camouflage that allows them to blend in with the leaves they're eating, making them harder to see. Watch out for butterflies fluttering near plants, landing on leaves and laying eggs. That's a dependable sign Caterpillars are sure to follow.
Sawflies and Rose Slugs
These Wasp relatives produce larvae that resemble Caterpillars or Slugs. In fact, one of the most common sawfly larvae is better known as Rose Slug, and frequently targets roses. As it feeds, it creates irregular holes that don't extend all the way through a leaf, leaving a paper-thin leaf membrane behind. The holes appear transparent, almost like a green window pane. Other types of Sawfly larvae cluster along leaf edges. Up to a dozen of these worm-like creatures could be feeding on the same leaf.
Japanese Beetles and Grubs
Shiny, metallic green Japanese Beetles feed on the flowers and leaves of many plants, including roses. They feed on the inner part of the leaves, eating the tissue between the veins, creating a skeletonized look. The creamy white, worm-like larvae are called White Grubs or lawn Grubs. Their feeding causes irregular brown patches in lawns, especially in late summer or fall.
Earwigs or Pincher Bugs
These fierce-looking, although harmless bugs, with their rear-end "pinchers," feed on dead and living organisms, including insect eggs, adult Aphids and decaying organic matter. But they also like to eat soft fruits (peaches, apricots, berries), and new growth and flowers of many types of plants. Look for regular holes along leaf edges or inside the leaf blade. On seedlings, they'll eat the whole plant – leaves and stems. You'll often find Earwigs hiding inside blossoms or growing shoots.
Leaf-Cutting Bees, good or bad?
These are welcome pollinators but can cause damage to ornamental plants, especially roses. As they feed, they cut distinct, clean edged, half-moon disks along leaf edges. They use the leaf material to line the cells in the nests where they lay eggs. Control measures not recommended.