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  • George R. Lee

Box Tree Moth Invasion Impacting Boxwood Shrubs

Box Tree Caterpillar
Photo by Didier Descouens via Wikipedia

Dr. David Smitley at Michigan State University perhaps states it best on the MSU web site, " Box tree moth will destroy most boxwood shrubs in the country if it becomes established". As of 2022 there have been 3 confirmed locations in Michigan where box tree moth has been found. Based on "official" sightings we must be concerned about all the box tree moth infestations we haven't found yet. Not to defame anyone but we had similar "official", "isolated findings" of emerald ash borer which turned in to devastating losses of ash trees within and beyond the borders of Michigan. As boxwood shrubs are used in abundance in landscapes we certainly want to take every precaution

possible to stop and control this pest. We don't need another pest destroying our landscapes.

Boxwood comparison after boxwood moth damage
Photos courtesy of the U.S. Department of Agriculture

Currently MSU is asking growers, nurseries, landscapers, arborist, and even homeowners to perform normal scoutings for box tree moth. They're also suggesting placing box tree moth pheromone traps and report any positive or suspicious findings to them. However, realistically most home owners simply don't have the time to go around the yard every day looking for this pest, don't want to deal with purchasing and hanging traps, or don't have the skill set to know what they're supposed to be looking for .

Box tree caterpillar feeding.
Photo by ABesheva via Wikipedia

Box tree moth feeds and damages boxwood shrubs while in their caterpillar stage. Symptoms and signs your shrubs may be getting eaten by box tree moth include: lime green larvae with black stripes and white hairy spots . Box tree moth eats the leaves and bark leaving a webbing from caterpillar silk and eventually killing the boxwood shrub or shrubs.

Currently the recommended proactive care and safe-guarding (other than trapping and inspecting) is to apply a timely, label approved insecticide treatment in July and another treatment in September. Weather can alter timing of application so it is best to consult with your local arborist.

Boxwood shrubs are also targets of pests such as boxwood leaf miner, boxwood spider mites, and boxwood psyllid. Don't forget that boxwood shrubs are acid loving soil type shrubs and that they do not like to be over watered or planted in wet areas of any landscape.

Don't know the condition of your boxwood shrubs or if you need to be more proactive in their care? Simply call the professionals at Branch Tree Service, Inc. Our arborist are here to help you with all of your tree and shrub health care concerns.

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