The box tree moth, an invasive insect already a serious pest in Europe may have been accidentally introduced into the United States through landscaping materials.
Jon Zawislak, extension entomologist for the University of Arkansas System Division of Agriculture, said the moth may have come to the U.S. through a shipment of boxwoods from Canada this spring.
“Canadian boxwoods were shipped to seven states: Connecticut, Massachusetts, Michigan, New York, Ohio, South Carolina, and Tennessee and many of the potentially infested plants were then moved to other states – including Arkansas,” Zawislak said. “The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service is looking to find all infested boxwoods and destroy them as soon as possible before these devastating moths have a chance to become established.”
Zawislak said USDA-APHIS is working closely with the affected states, including Arkansas to find and destroy the imported plants in the receiving facilities. The agency is also trying to trace the sale of imported plants to determine additional locations of potentially infected boxwoods.
USDA-APHIS will provide box tree traps and lures for surveys in the receiving facilities and other locations that received potentially infected plants, he said.
“If you bought a boxwood plant during spring 2021, please inspect it for signs of the moth and report any findings to your local USDA office or state agriculture department,” Zawislak said.
In Arkansas, any findings should be reported to Paul Shell, plant inspection and quarantine program manager for the Arkansas Department of Agriculture. Call 501-225-1598 or email: firstname.lastname@example.org.
On May 26, USDA-APHIS halted importation of boxwoods and two other species, including euonymus and hollies, which are also known to host the moth.
“This is the first known introduction in the United States, and if we can act quickly and thoroughly, we can prevent this pest from becoming established,” Shell said.
Pupae typically first appear in April or May and will be present through the summer and into the fall, depending on the local climate and timing of generations. Adults first emerge from the overwintering generation between April and July, depending on climate and temperature. Subsequent generations may be active through June to October.
Adults have two color forms, light and dark, and typically live for two weeks after emergence. The wings of the light form moth are white to off-white in the center, with a broad, dusky margin. The dark form is dark gray with two small triangular spots on each wing.
Female box tree moths lay flattened eggs singly or in overlapping clusters of five to more than 20 at a time in a gelatinous mass on the underside of boxwood leaves. Eggs are approximately 1/16 inch in diameter. Female moths can produce more than 42 egg masses in their lifetime. Eggs typically hatch within four to six days.
Once they emerge, the caterpillars will begin feeding on foliage and spinning webs around leaves and twigs to hide and protect themselves from predators. They can grow to be 1.5 inches. The caterpillars are green with. both black stripes and thinner white stripes running the length of their bodies. They also have rows of black spots, from which emerge short, thin spines.
"It may be a low likelihood that we will find any here in Arkansas, but we're better off safe than sorry,” Zawislak said. “When a new insect species is accidently introduced, we typically have a very short window of time to find and eradicate it before it becomes permanently established and impossible to get rid of. A lot of agencies are working hard right now to see if we can locate and eliminate this pest right away."
For more information and pictures of box tree moths, visit https://www.uaex.uada.edu/environment-nature/ar-invasives/invasive-insects/box-tree-moth.aspx.