To most people, the buds and sprouts of April are welcome heralds of spring. But to some farmers and scientists in the southeastern corner of Pennsylvania, these signs mark the beginning of a long season of dread.

Their worry is Lycorma delicatula, the spotted lanternfly. It is an invasive pest with a voracious appetite and remarkable reproductive talents.

Native to Asia, lanternflies first appeared in Pennsylvania in 2014. Despite a quarantine effort, they have also been discovered in small numbers in New York, Delaware and Virginia.

In their native range, lanternflies feed primarily on one type of tree — Ailanthus, the tree of heaven. The trees are an invasive species, too, common across the continental United States, and so entomologists fear lanternflies one day may spread to far-flung corners of the country.