5 Vegetable Pests You Should Know About

Canada’s chilly winters and short growing season limits insect populations, especially when compared to warmer climates. However, pests can still inflict plenty of damage to vegetable crops.

Read on for information about five of the most common vegetable pests, and learn basic methods of keeping them in check.

1. Aphids are common pests, and although they’re tiny, they’re extremely destructive, killing vegetable plants by sucking out the sweet juices. Aphids are easy to recognize because they tend to group, en masse, on the stems and undersides of leaves.

Insecticidal soap spray usually keeps aphids in check, but you may have to spray every couple of weeks. Avoid pesticides, as you’ll kill powerful natural predators such as ladybugs and lacewings.

2. Cutworms are fat, brown or gray larvae measuring about 2.5 to 5 cm in length. This pest, which chews through plant stems at ground level is especially troublesome in May and June and can destroy an entire row of young plants in a single night. You may want to create cardboard collars for plants, such as milk containers with the bottoms removed.

Wait as long as possible to move vegetable plants outdoors in spring, as cutworms feed early in the growing season. Hand-pick cutworms off the soil after dark, as well as those curled just below the surface. You can also sprinkle a line of diatomaceous earth around the plants, as the gritty substance will kill worms that dare to cross over.

3. Tomato hornworm is a difficult pest, partly because it blends in well and is difficult to spot on tomato plants. This pest hides under the leaves during the day, dining on foliage at dusk and on overcast days.

Handpicking is the easiest and safest way to control tomato hornworm. Avoid pesticides and encourage natural predators such as braconid wasps, lacewings and ladybugs.

4. Squash bugs kill squash, cucumbers, and melons by sucking the sap from the leaves. The large, flat pests are usually dark brown or dark gray with orange and brown stripes on their abdomens. Controlling them is challenging because they quickly hide under leaves when disturbed.

Keep the area free of plant matter during the growing season, and continue into fall to reduce overwintering. If you have a small garden, control squash bugs by picking them off by hand. Otherwise, lay out newspaper traps at night. Squash bugs will crawl underneath and you can destroy them in the morning.

5. Slugs and snails are among the nastiest and most pervasive garden pests, chewing their way through vegetable plants at night and in the wee hours of the morning. If you have the stomach for it, you can pick the slimy pests off by hand and drown them in a bucket of water.

To discourage slugs and snails, keep your vegetable garden clean and free of leaves and plant debris. Limit mulch to a very thin layer. Diatomaceous earth sprinkled around plants will kill slugs by abrading their skin.