Early Signs Of A Box Tree Moth Infestation You Shouldn't Ignore

Boxwoods (Buxus spp.) are popular evergreen shrubs that are perfect for plant sculpting and are often used to create stunning hedges. However, if you have any of these in your yard, there's an invasive pest you should familiarize yourself with so that you can spot any early signs of infestation, which could be fatal for your plants. The pest in question is known as the box tree moth (Cydalima perspectalis), which is native to East Asia. Unfortunately, this destructive insect has made its way to the U.S. It was first reported in 2021 in New York, but more recent reports have confirmed the pest's presence in Delaware, Massachusetts, Michigan, Ohio, and Pennsylvania. Early signs of an infestation can include leaves that have been eaten or skeletonized, young caterpillars visible on the foliage, webbing on the undersides of the leaves, and sawdust frass.

The adult moths can often be hard to spot because they're mainly active at night, but they can be either white or brown with distinct markings on their front wings. The caterpillars are far easier to identify as they're lime green in color with black stripes. They also have white spots, are covered in hair, and have a shiny black head. They can grow to a length of 1 inch, depending on their growth stage.

Even if you don't live in the states mentioned, you should still monitor your box plants to watch out for these early signs of box tree moth infestations. Look out for leaf damage, such as sections that have been eaten, especially inside the edges. Leaves that appear skeletonized are also a good indication that the caterpillars are active on your plants. If you notice this type of damage, look for the lime-green larvae among the foliage. Check the undersides of the leaves for a distinct silk webbing that is housing the pupa. If you spot signs of the box tree moth on your plants, you should immediately report them to your state's plant regulatory official or your state's plant health director.

You might even spot a sawdust-like substance, which is the caterpillar's excrement and is commonly referred to as frass. This may be visible on the foliage or even under the base of the shrub. Noticing these signs early may allow you to save your box plants if infestations are fairly localized. In this case, you can just cut off the affected branches, double-bag them in plastic, and dispose of them in the trash. For more severe cases, entire plants may have to be removed and destroyed to prevent the spread of the pest. It helps to familiarize yourself with what you should know to stop the box tree moth in its tracks. If all else fails, rest assured that there are plenty of other evergreen shrubs to make your landscaping look great that you can grow instead of boxwoods.