This lilac is infested with scale insects that form a gray to dark brown protective cover called a test that looks like an oyster shell or mussels. It is an insect pest of more than 130 species of plants. (Courtesy MelindaMyers.com)
Like us, insects spend their winters in different places. Unlike us, they spend their winters in different stages of development. Some may be wintered as adults, others in their immature stage as grubs, caterpillars, or nymphs, while others will be in the pupal stage as a chrysalis or cocoon. Understanding their life cycle and location can help us support beneficial insects while managing problem insect pests.
Invite helpful insects like beetles, parasitic wasps and predatory mites to your landscape to help manage plant-damaging pest populations. Add a birdbath to encourage insect-eating songbirds in your gardens. Most songbirds eat insects or feed them to their young while adding color, movement and fun to your garden.
Keeping your plants healthy with proper care is the first and most important step in any pest management strategy. Healthy plants are better able to tolerate pest attacks and are more likely to recover from damage.
Despite your efforts, insect pests can attack and damage your plants. Predatory birds and insects often manage small populations, but there may be times that decide to intervene. Winter is a good time to monitor and, in many cases, manage insects that damage plants.
Scale insects can be one of these and come in a variety of colors and shapes, but they all grow and reproduce under a wax cover. This cover protects them from predators, desiccation and pesticides. Depending on the scale species, they can overwinter as an immature scale, a fertilized female, or eggs under the protective cover.
Treating the scale of damage to the plant in late winter or early spring is a way to skip the control of this pest while having minimal or no impact on the beneficial insects that help manage it this plague Take some time to check the plants for troublesome pests like the invasive oyster scale.
This insect is not native to North America and is a pest of more than 130 plant species including poplars, ash, beech, maple, willow, hornbeam, cottoneaster and lilac. Adult scale insects form a gray to dark brown protective mat called a test that resembles an oyster shell or mussels. In autumn, the mated female lays 20 to 100 eggs in the test, dies and the eggs remain there throughout the winter.
The removal of heavily infected branches and branches is an option when the scale population is contained in a small part of the plant. You can also throw away the ladder with branches and stems with a plastic washer. Be careful not to damage thin-barked plants.
Another option is to apply light organic horticultural oil such as Summit Oil spray for the whole year when the plants are dormant. The temperature should be 40 degrees or higher when it is treated. As always, read and follow label directions for effective and safe control. Since the eggs are so well protected, a second application of horticultural oil can increase success. Make a second application, if necessary, when the eggs hatch and the immature insects known as crawlers emerge in the spring after the buds have hatched.
When planning your landscape this winter, pay special attention to stressed plants and those susceptible to oyster scale and other common insect pests in your area. Plants exposed to road dust and pesticides can also be more vulnerable, as these conditions have a negative impact on predators and parasites that help manage plant pests.
Regularly checking plant health, working with nature, and strategically managing invasive pests like oyster scale can help improve the health, vigor, and longevity of your landscape plants.
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Melinda Myers has written more than 20 gardening books, including Midwest Gardener’s Handbook, 2nd Edition and Small Space Gardening. She hosts the Grandi Courses”How to Grow Anything “Instant Video and DVD Series and national unions Melinda’s Garden Moment radio program. Myers is a columnist, a contributing editor to Birds & Blooms magazine, and was commissioned by Summit for her expertise in writing this article. Their website is MelindaMyers.com.
