Boxwoods (Buxus spp.) are favored evergreen shrubs, ideal for plant sculpting and frequently used to form beautiful hedges. However, if you have these in your garden, you should be aware of an invasive pest to detect early infestation signs that could harm your plants. The pest is the box tree moth (Cydalima perspectalis), originally from East Asia. Unfortunately, this damaging insect has arrived in the U.S., first reported in 2021 in New York, with recent sightings in Delaware, Massachusetts, Michigan, Ohio, and Pennsylvania. Early infestation indicators include leaves that are eaten or skeletonized, visible young caterpillars on the foliage, webbing beneath the leaves, and sawdust frass.
Adult moths are usually elusive due to their nocturnal activity, appearing either white or brown with distinct wing markings. The caterpillars are more identifiable, being lime green with black stripes, white spots, hair-covered, and possessing a shiny black head, growing up to 1 inch depending on their development stage.
Important early indicators to observe
Even if you’re not in the states listed, it’s crucial to inspect your box plants for initial signs of box tree moth infestations. Watch for leaf damage, such as eaten sections, particularly along the edges. Skeletonized leaves suggest active caterpillars on your plants. If you see this damage, search for the lime-green larvae within the foliage. Examine the undersides of leaves for characteristic silk webbing containing the pupa. If you detect signs of the box tree moth, report them promptly to your state’s plant regulatory official or plant health director.
You might observe a sawdust-like material, the caterpillar’s waste known as frass, on the foliage or beneath the shrub. Early detection can help save your box plants if infestations are localized. You can remove affected branches, double-bag them in plastic, and dispose of them in the trash. For severe cases, entire plants may need removal and destruction to prevent pest spread. Understanding how to stop the box tree moth is beneficial. If necessary, remember there are numerous other evergreen shrubs to enhance your landscaping in place of boxwoods.
