The Garden Blog

Box Tree Moth (BTM) populations are rapidly increasing in some Northeastern Cincinnati suburbs. This insect pest, when in the form of a caterpillar, rapidly consumes the foliage and the bark of boxwood shrubs. This feeding results in the defoliation, damage, die-back and/or death of plants. It is possible the population of this insect pest will grow and spread to other parts of the Cincinnati area. This is concerning as boxwood shrubs are a popular plant for landscaping. 

What Is Box Tree Moth? 

Box Tree Moth is a non-native insect pest that originates from Asia. It targets boxwood plants and is not known to affect other species of plants. The lifecycle of this insect involves many stages – egg to caterpillar to pupa to moth. It is in the caterpillar stage of the lifecycle that the insect causes damage to boxwood plants.

Why Is Box Tree Moth Harmful? 

Boxwood shrubs are used extensively in commercial and residential landscaping throughout Southwest Ohio. Box Tree Moth, in the caterpillar stage, consumes and rapidly defoliates boxwood shrubs. The population of caterpillars on a single plant can increase rapidly and so can the damage they cause. If the infestation is caught and treated, the boxwood plant/planting will likely grow new foliage and recover. 

The extent of damage caused by the Box Tree Moth is noted by the Ohio State University Extension in their Box Tree Moth Fact Sheet series… “[Box Tree Moth] caterpillars may also consume the bark and phloem on small twigs (Sisk et al., 2002). This usually occurs in heavy infestations after the caterpillars have consumed all the leaves. Bark damage reduces the capacity for shrubs to recover by sprouting new growth and leaves from buds. Heavy, continual leaf loss and stem damage from BTM throughout the growing season may kill boxwood plants”. 

Evidence of infestation of Box Tree Moths includes: rapid damage and defoliation causing plants to change color from green to a golden yellow or brown in a couple of weeks, curlicue leaf damage, the presence of the BTM caterpillar, webbing, and frass (insect excrement in the form of small pellets). 

Where is Box Tree Moth Currently? 

Box Tree Moth was first detected in North America in 2018 and then found in Ohio in 2023. Local infestations of Box Tree Moth are found east of I-75, in the areas of Loveland, Symmes, Montgomery, Indian Hill, and Mariemont. The population is likely to spread to surrounding communities.

What Can A Homeowner Do About Box Tree Moth? 

1. Monitor and investigate boxwoods for symptoms of Box Tree Moth. Unfortunately, the efficacy of preventative insecticides is not certain at this time. 
2. If detected, an infestation of Box Tree Moth can be treated with: 
   1. Bonide’s Eight Insect Control for the quickest results. This product must make contact with the BTM caterpillar and results can be seen within hours. Repeated applications necessary – see product label for more information. 
   2. Bonide’s BT products. This product targets worms and caterpillars while not harming beneficial insects such as bees. The product must make contact with the BTM caterpillar and results may take several days. Repeated applications necessary – see product label for more information. 
   3. Fertilome’s Spinosad for organic control. This organic product is effective on worms and caterpillars among other insects. Spray the foliage and BTM caterpillars. Results may take several days. Repeated applications necessary – see product label for more information. 
   4. Hi-Yield’s Bug Blaster II Bifenthrin for longer lasting control. Spray foliage and BTM caterpillars. Residual on the foliage provides longer-lasting protection against caterpillar damage. Follow-up applications needed but, because of residual, not as frequently as other products. See product label for more information. 
3. Boxwoods damaged by Box Tree Moth infestation may not be dead. However, they may not regenerate new foliage until later in the season or the following spring. After controlling the infestation of BTM, a hands off approach is best. Don’t water or fertilize the plant until it appears that it is regrowing. 
4. If after the following spring the boxwood does not generate new growth, replace the plant. 5. When installing new plants, consider using multiple species of plants in the landscaping, rather than one species. This will minimize the damage caused to landscaping by a future disease or insect infestation.

Additional Information 

Box Tree Moth: Range And Spread. Part 1 of 3 BTM Series. August 19, 2025.
https://ohioline.osu.edu/factsheet/ent-0099 

Box Tree Moth: Detection. Part 2 of 3 BTM Series. August 19, 2025. https://ohioline.osu.edu/factsheet/ent-0100 

Box Tree Moth: What Should You Do? Part 3 of 3 BTM Series. August 19, 2025.
https://ohioline.osu.edu/factsheet/ent-0101