Your Guide to Controlling Common Pests on Your Landscape Plants – Part 2: Borers and Beetles!
Welcome back! In our previous blog, we covered sucking pests like aphids, whiteflies, and scale insects, as well as ways to control them to keep your plants healthy and lawn looking its best. Now it's time to talk about chewing pests and boring pests—the ones that can leave visible holes in leaves or secretly weaken your trees by burrowing into their bark.
Chewing Pests: The Leaf Nibblers
Chewing pests are the ones responsible for the holes, missing leaf tissue, and general destruction of your plant's foliage.
Tent Caterpillars
Host Plants: Plum, peach, apple, hawthorn, oaks, and others
Damage: These pests form webs in tree branches and strip leaves.
Appearance: Black larvae with brightly colored stripes that get to about 11/2 inches long.
Control: Inspect trees and prune out webs early in the season. Apply insecticides like Bacillus thuringiensis (Dipel), carbaryl (Sevin), or diazinon directly to the webs when caterpillars are present.
Fall Webworms
Host Plants: Many ornamental trees and shrubs, including oaks and pecans, as well as broadleaf and coniferous trees and shrubs
Damage: Webworms form large webs around branches, defoliating the host plant.
Control: Prune and destroy webs, then apply insecticide like Bacillus thuringiensis (Dipel) for effective treatment.
Bagworms
Host Plants: Broadleaf and coniferous trees and shrubs
Damage: Bagworms create protective silken bags as they feed, causing defoliation.
Appearance: Dark colored larvae inside 1-2 inch brown or gray colored tear-shaped "bags" that are usually covered in leaves, twigs, and other debris.
Control: Remove bags by hand and use insecticides like carbaryl or acephate for larger infestations.
Various Beetles (e.g., Japanese Beetles)
Host Plants: Many shade and ornamental trees
Damage: Beetles skeletonize leaves, causing defoliation.
Appearance: Beetles vary in size, shape, and color, but common species like the Japanese beetle are around ½ inch long, with a shiny, metallic green body and copper-colored wings. They often have a row of white tufts of hair along the sides of their abdomen. Other beetles, such as the Southern beetle or the European chafer, can also be found on trees and shrubs. They typically have hard, shell-like bodies, often brown or black, and may leave behind characteristic holes in leaves as they feed.
Control: Regularly inspect plants during peak feeding times, and apply insecticides as needed.
Fall Armyworm
Host Plants: Various vegetables, crops, and grasses, turfgrass
Damage: These pests are known to defoliate turfgrass quickly, leaving brown patches in your lawn.
Appearance: Fall armyworms are typically 1.5 inches long, with light green to dark brown bodies and distinct light and dark striping. They are often found in large groups, especially when they are actively feeding.
Control: Monitor your lawn and garden for early signs of infestation, such as chewing damage and the presence of caterpillars. Apply specific insecticides for fall armyworms as soon as they are detected. For a more environmentally friendly approach, use beneficial nematodes to target the larvae. Timing is critical—treat early in the infestation before the caterpillars mature and spread.
Boring Pests: The Silent Threats
Unlike chewing pests, boring pests quietly damage trees by burrowing into the bark, weakening the plant over time.
Asian Ambrosia Beetle
Host Plants: Oak, pecan, hickory, crape myrtles, dogwoods, and others
Damage: The Asian Ambrosia Beetle (or Granulate Ambrosia Beetle) leaves sawdust-like "toothpicks" around the base of the tree by burrowing into the trunk.
Appearance: This beetle is small (about 1/8 inch long) with a reddish-brown to black body. It has small, rounded wings and is difficult to spot unless you notice the characteristic "toothpicks," around the base of the tree.
Control: The best way to prevent infestations is to keep trees healthy through proper watering, pruning, and fertilizing. If it is too late for that, remove and dispose of plant material, and apply protective treatments.
Emerald Ash Borer (EAB)
Damage: This borer causes canopy dieback and leaves distinct D-shaped exit holes.
Appearance: The adult Emerald Ash Borer is about ½ inch long and metallic green with a purple abdomen underneath its wings. The larvae are white, legless, and about one inch long when fully grown, feeding under the bark, and creating winding tunnels. The distinctive D-shaped exit holes in the bark are a key sign of infestation.
Control: Apply systemic insecticides for prevention, especially in areas where EAB is prevalent. Remove affected trees to prevent the spread.
Goldenrod Locust Borer
Damage: These beetles burrow into the stems of goldenrod plants, weakening them.
Appearance: The adult goldenrod locust borer is a black and yellow beetle with slender antennae and is about ½ inch long. The larvae are creamy white, legless, and burrow into the stems of the plants.
Control: Inspect plants regularly for signs of damage and remove infested stems. Treat severe cases with insecticides. Consider planting resistant species or varieties of goldenrod to reduce the risk of infestation in future seasons.
Final Thoughts: A Healthy Landscape Starts with Prevention
Maintaining a healthy landscape requires more than just watering and fertilizing—it involves being proactive in pest management. By regularly inspecting your plants, using the right pest control strategies, and encouraging beneficial insects, you can keep your garden thriving all year long.
As we've seen, different pests require different approaches. Whether it's the tiny aphids and mealybugs or the larger chewing and boring pests, timely intervention can make all the difference.Stay vigilant and use the right tools for each pest problem to protect your landscape from damage.
If you need more personalized advice or pest control help, don't hesitate to reach out to a local lawn care professional for assistance. A healthy, thriving yard is possible with the right care and knowledge!
