Are you a night owl? If so, you have something in common with a few of our garden pests — those who feed mostly at night. Let’s look at three that love to munch on some of our favorite plants: root weevil, earwig, and tobacco budworm.
Many species of root weevil feed on a variety of landscape plants, including azaleas, rhododendrons, and roses, as well as small fruits like raspberries and strawberries.
Although different species of root weevils attack a variety of landscape plants, they have several characteristics in common. Adults tend to be brownish to black colored and approximately ¼-inch or a little longer. Flightless, they are easily identified by their elongated snout. Their larvae — white and legless with brown heads — feed on the roots but have been known to girdle lower stems, as well.
For most ornamentals, the adults are the primary problem. To determine if you have a root weevil problem, check your plants for semi-circular or irregular notches on plant leaves. If so, go into your garden after dusk with your flashlight and look for the beetles. You can pick them off, knock them off onto a beating sheet or cardboard box, or capture them in pitfall traps.
Pesticides and biological control methods are available to help control root weevils. For specific recommendations, contact the WSU Master Gardener Plant Diagnosis Clinic at 667-6540.
Many gardeners are familiar with the reddish-brown earwigs with their telltale pincers on the rear end. Like root weevils, they feed at night and enjoy a smorgasbord of many of our plants, such as home tree fruits, flowers like marigolds, zinnias and dahlias, and the seedlings of lettuce, celery, beets and carrots, among other vegetables.
Unlike root weevils, earwigs can be beneficial in our gardens, eating pests such as aphids and mites. Earwigs can fly, but rarely do. During the day, they rest in moist, shady places and beneath boards and stones.
When feeding, earwigs create holes in a plant’s leaves. They chew shallow, irregular areas into the surface of fruit. Shoot tips fed on by earwigs often fail to develop and can result in stunted growth.
WSU does not recommend the use of pesticides on earwigs. Instead, keep your garden free of their daytime hiding places. You can also place rolled newspapers, burlap bags or flat boards beneath the affected plants for both monitoring and trapping earwigs. Pick them out from under your “traps.” As with root weevils, look for them on your plants after dark. You can shake earwigs off flowering plants into a box lid or something similar.
The tobacco budworm, a problem for flowers such as geraniums, petunias and roses, is the larvae of a small, light-green moth with cream-colored bands. These caterpillars tend to be light yellow to yellow-green when young. Older larvae come in different colors, but usually have stripes along the side and a brown head.
Flower buds are the favorite food of the tobacco budworm. The moth lay their eggs on blossoms, fruit or shoot tips. Buds damaged from feeding larvae may fail to open. If buds open, you will notice the flowers and leaves will appear tattered.
Look for larvae at dusk and pick them and any infected buds off your plants. Small holes in buds and flowers and caterpillar droppings can help you find them. As with the root weevils, contact the Master Gardener Plant Diagnosis Clinic for specific chemical management options.
While out in your garden with your flashlight, keep an eye out for some of the other common garden pests that may be lurking, such as aphids, scale, and slugs.
A WSU Master Gardeners of Chelan County column appears weekly in The Wenatchee World. Casey Leigh is one of four columnists featured.