A DNA test to identify an invasive pest in its juvenile stages has been developed by scientists at the University of Hawaii.

The new technique, described last week in the Journal of Economic Entomology, could be a significant step toward keeping the coconut rhinoceros beetle from becoming widespread, the scientists said.

The coconut beetle and another species, the oriental flower beetle, look the same until they’ve grown up, which makes early detection difficult. Until now egg or larvae samples from the field have had to be raised in a lab, which takes weeks, before scientists could determine which species they were looking at.

But now a genetic testing method can identify the species with a sample from eggs, larvae or poop in a matter of hours.

The new method will help “ensure that eradication efforts are being directed at coconut rhinoceros beetle and not oriental flower beetle,” Michael Melzer, a researcher with the UH Department of Plant and Environmental Protection Sciences, said in a statement. “This assay will help to prevent any misidentification in the field.”

His co-author is Shizu Watanabe, also with the department.