Boxwoods are beautiful plants that add character and value to any landscape. Unfortunately, in recent years, we’ve seen the arrival of a pest that finds boxwoods too delicious to resist, putting them at high-risk of defoliation and irreparable damage. This pest is the Box Tree Moth.

These hungry caterpillars can completely destroy the leaves of your boxwoods leaving them withered, brown and beyond repair!

How do you spot it?

Frass: small and white and located on the underside of individual leaves. You can also look for leaves that have been webbed together.


Caterpillars: have black heads and green bodies with thick black stripes along their bodies.



How do you treat it?

Treat it with a BTK Foliar Spray: This is a treatment used to control other types of caterpillars as well, including gypsy moth and tent caterpillars. The treatment is highly effective in controlling caterpillars and is safe for the rest of your garden

  • Box Tree Moth has multiple life-cycles per season, so you’ll need to treat your boxwoods 4 times a year to control each new wave of infestation. Treatments are done from the first wave in late May/early June to late August/early September.

After-Care and Monitoring

Make sure to include a treatment of ArborGain™ biostimulant soil conditioner and a mycorrhizae inoculation in your treatment plan. This helps the plant recover from the stress put upon it by the infestation. It also boosts the immune system of the plant so it is better equipped to battle any future stressors.


Talk to your arborist today about protecting your boxwoods!


Be good to your trees.


Kristie Nairn, MA, MMst
Cohen & Master Tree and Shrub Services Ltd.