Customs officers at Detroit Metropolitan Airport checking the baggage of a passenger traveling from the Philippines found something only about an inch in size that piqued their interest.
The objects in question — the larvae and pupae of an unidentifiable insect — were contained in seed pods that the passenger said were intended for medicinal tea. Later, scientific tests showed that the agents had identified a potentially serious threat to the country’s agriculture and natural habitats.
US Customs and Border Protection announced last week that the pupae had hatched a species of moth last observed by scientists in 1912 in Sri Lanka. Experts confirmed that such non-native insects had the potential to defoliate forests and feed on or infest crops.
The moths, whose black-and-gold stippled wings resemble a cloudy morning sky, were discovered in September and appeared to be members of the Pyralidae butterfly family, customs officials said. To determine their exact species, authorities sent the specimens to an expert at the Smithsonian Institution, according to the announcement.
The species of moth was Salma brachyscopalis Hampson, named after British entomologist George Hampson, according to Jason Dombroskie, a lepidopterist at the Insect Diagnostic Lab in Cornell who specializes in identifying moth species. mr. Dombroskie said in a telephone interview that he trained one of the agricultural specialists at the Detroit airport in the taxonomy of moths and that the specialist told him about the discovery.
Mr. Dombroskie and David Moskowitz — an entomologist, environmental consultant and co-founder of National Moth Week, an annual event that encourages people to observe moths in backyards and parks — said the moth was unlikely to have been smuggled into the country. They said the strain was too obscure to possess the medicinal or aesthetic value that motivates smugglers.
But both experts emphasized the danger the species could pose given the destructiveness of other non-native insects.
For example, the spongy moth (until recently known as the gypsy moth) has become a tree-devouring pest responsible for hundreds of millions of dollars in damage and mitigation efforts each year, according to the Entomological Society of America.
And scientists have feared that the emerald ash borer, an Asian beetle, has the potential to kill 99 percent of the country’s ash borers.
“The emerald ash borer originated in Detroit,” said Mr. Dombroskie. “If we had had an agricultural inspector who noticed that early, we could have prevented all of that.
“Could this moth have become the next billion-dollar plague?” he asked, referring to the species found by the customs officers. “Probably not — but it’s possible.”
The identification of such small but potentially devastating larvae was “unlikely,” said Mr. Dombroskie.
“You can only know so much,” he added. “A botanist may not have made this discovery, or a mycologist,” someone who works with fungi such as fungi and mushrooms.
Mr Moskowitz said the episode illustrated the importance of animal taxonomy training for customs officials.
“Identifying a moth that hadn’t been found for over a century took a lot of expertise,” he wrote in an email. “Without it, we lose the ability to know what’s around us, how to protect and conserve species at risk and from intruders.”
With the global supply chain connecting countries and travelers shifting between world capitals, Mr. Moskowitz continued, protecting the country from invasive pests “really is a mammoth task.”
