Boxwood leaf minor and moth


I live in Etobicoke Ontario and my Boxwoods are clearly all infected with both moth and leaf minor. The infestations seem to be quite extensive on all plants. What is my best treatment option at this time? or should I consider replacing them ( any recommended species? )
many thanks


Thank you for contacting the Toronto Master Gardeners concerning your boxwood.

We have numerous posts on our website concerning the treatment of boxwood moth as well as boxwood leaf miner. Simply type Boxwood into the Find it Here bar located to the right of the page.

The following information is from one of our archived posts on boxwood moth:

Unfortunately this pest has arrived in Toronto specifically in the last 18 months (it is not yet in the United States), and Landscape Ontario is trying hard to track cases and reduce it’s spread in the future.  The links below may be the same ones that you found in your research.  Please use the links provided in the articles to report your location and actions to them, as they may wish to follow up.

Your BTK application appears to be correct, if perhaps a little late to stop the moths this season.   You can keep spraying every 5 – 7 days as long as you see any caterpillars or pupae on the plants.   There may still be another cycle of the pests hatching on the plants that you can treat throughout the fall.

Fortunately, boxwood is normally a pretty tough and hardy shrub, so you can prepare to fight this battle again next year, and Landscape Ontario may have issued more instructions as they get data on the behaviour of the moth.”

For additional information refer to Boxtree Moth Caterpillars and Larvae

Boxwood Leafminer (Monarthropalpus flavus), is the larva (immature form) of a small, orangish mosquito-like fly. Here is a link to a previous Toronto Master Gardener posts on ‘time to deal with boxwood leaf miners’, which you may find informative: Boxwood leafminer, Boxwood Shrubs Infested

Lastly, this link on Boxwood alternative will provide alternatives to your boxwood should you decide to replace them..

May 13, 2021