Identifying and Dealing with Problem Insects

Gardeners often play detective when figuring out what's chewing holes or causing yellow or brown spots on favorite plants. Here are some clues to help solve common garden mysteries, as well as tips for dealing with pests.
inspect plants closely

inspect plants closely

Investigate damage to plant leaves, stems and fruit to determine what pests may be present.

Locate the Suspect

Start by inspecting your plants closely. Look for the culprits under leaves and between plant stalks. Many pests stay on the plant at all times, and a close and thorough look will reveal the source of the problem. Other pests run or fly when disturbed, so you may need to "sneak up" on them. For instance, if you see a cloud of tiny, pale moth-like bodies fluttering above your plant, you may have a whitefly infestation. Some pests come out at night to feed, so you may need to check after dark using a flashlight. Snails and slugs, for example, tend to do much of their foraging in the cool and damp of the evening.

Once you've found the pests, then next step is do identify whether you have the "chewing" or "sucking" variety. This is critical since the specific steps you take in controlling and treating for insect pests are determined by the particular types that are attacking your plants.

snails and slugs are most common garden pests

snails and slugs are most common garden pests

Slugs and snails are among the most common garden pests.

Photo by: VideoFocus


Varieties of Pest: Chewing Types

You likely have this type if your plants have leaves that are half-eaten--perhaps with foliage that looks like a "leaf skeleton." Chewing insects tend to eat on the leaf material between the veins. Distinct holes in the leaves also indicate the presence of chewing pests.

sucking pests pierce surface of leaf

sucking pests pierce surface of leaf

Inspect both sides of the leaves for pests making a home in your garden.

Common chewing pests include:

Snails and slugs are one of the most common garden pests. They typically start eating from the outer edge of leaf. They prefer to stay where it's dark and cool, so inspect the underside of leaves for snails, slugs or the tell-tale silvery trail of "slime" they leave behind.

snails and slugs are attracted to beer

snails and slugs are attracted to beer

Slugs can't resist beer. Pour a bottle of beer into a pie dish and leave in your garden overnight.

Earwigs, in their adult form, are the familiar "pinching" beetle. They eat both plant and animal matter and, in particular, are known to target Dahlias, Zinnias, marigolds, roses, lettuce and strawberries.

Caterpillars, cutworms and hornworms are among the most damaging of the chewing pest variety. They may chew into the plant's stem at ground level. One indicator that you have caterpillars or cutworms is the waste they leave behind in the form of black or green pellets.

ladybugs are natural way of getting rid of aphids

ladybugs are natural way of getting rid of aphids

Ladybugs are a natural and effective means of getting rid of aphids. Simply buy them by the bag at your nursery and set them free in your garden.

Varieties of Pest: Sucking Types

These types pierce the surface of the leaf or stem and suck nutrients out of the plant. Indicators of the sucking variety of pests include discolored, mottled, twisted or curled foliage.

homemade mixture will deter number of garden pests

homemade mixture will deter number of garden pests

A homemade mix of garlic, cayenne pepper and minced onion in a dilute soap-and-water solution will deter a number of garden pests.

Common sucking pests include:

Aphids are small, winged insects. They particularly like new plant growth.

Whiteflies are a small white insect--not a true fly, but actually a relative of the aphid. They're frequently found on the undersides of leaves.

Tips for Controlling Slugs and Snails

Remove excess moisture.

Snails and slugs are attracted to the yeasty odor of beer. Put out a shallow dish of beer overnight. Slugs will crawl into it and drown.

Consider "slug-resistant" plants. Some popular backyard plants that are resistant to snails and slugs include Begonias, Fuchsias, Geraniums, Impatiens and nasturtiums.

Try using copper tape (available from nurseries and garden centers) to protect trees and plants from slugs and snails.

Tips for Controlling Aphids

One of the simplest methods for removing aphids from plants is to use a strong stream of water from a hose and sprayer attachment to knock them off leaves.

You can create your own aphid deterrent by using one tablespoon dishwashing liquid to a gallon of water. Spray the solution onto the leaves.

Release lady bugs or praying mantis. Both of these insect species are beneficial to gardeners since they are predatory species and feed on other insects--including pest species.

Tips for Controlling Caterpillars

Homemade garlic and pepper sprays protect against cabbageworms, caterpillars, horn worms, aphids and flea beetles. Use 6 cloves garlic, 1 tbsp dried hot pepper, 1 minced onion, 1 tsp pure soap and one gallon of hot water. Spray the solution onto the leaves.
Release praying mantis.

Other Tips:
Other commercial products for controlling pests include insect netting and insecticidal soaps and oils

Sprinkle ground hot pepper directly onto leaves to deter chewing pests.
Know what bugs you're dealing with. When in doubt, take a leaf to a specialist. Check with your local nursery or agricultural extension.

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