Box Tree Moth Found in Canada

The Canadian Food Inspection Agency (CFIA) confirmed that box tree moth (BTM) was discovered in three separate residential landscapes in Etobicoke, Ontario, a Toronto neighborhood in fall 2018.

CFIA plans to assess the extent of spread and determine whether this is a transient, or not fully established, pest or if it is more widely distributed.

Surveys and outreach efforts to educate the local public are planned as well. Control measures and future plans for delimitation will be coordinated among CFIA, the Ministry of Ontario, and the boxwood industry.

APHIS is still evaluating the need for a federal order requiring certification of boxwood entering the U.S. from Canada; however, a pest alert bulletin was issued to ports of entry. Surveillance and monitoring along the border in addition to entry points will be heightened. Researchers are unsure how quickly BTM will spread in the U.S. Box tree forests do not exist here; so, less host material may (hopefully) translate to slower or less spread.

As with many insect pests, the most destructive life stage is larvae, or caterpillars in this case. Damage is caused by larvae feeding on leaves (aesthetic damage) and bark (physiological damage). Infestations are flagged by skeletonized leaves, frass deposits, and webbing created by caterpillars for protection during feeding and pupation. Adults are moths with a wingspan of about 1.5 inches, and wings are either white with a dark brown border or brown with small, white spots.

The ideal temperature range for BTM is from 70–92 °F, but activities are known to occur outside this range. Eggs hatch when temperatures are at least 52 °F, and larvae regularly survive winter temperatures below -22 °F in parts of China. Depending on temperature and light levels, two to four life cycles per year are common in the EU; each lasts around 45 days.

The Horticultural Research Institute (HRI), the AmericanHort research foundation, continues to monitor BTM as part of its ongoing Boxwood Initiative. Outreach on emerging pests and diseases is another example of how HRI helps the industry stay informed on issues impacting their bottom line.