Japanese beetles have turned up in North Dakota for only the second time in more than half a century, but officials do not believe it has anything to do with extreme drought in states where the destructive pests are more prevalent.
One expert thinks the bugs simply hitched a ride on trucks carrying nursery plants across the Minnesota border.
Infestations of the beetles that feast on everything from rose bushes to corn crops are found mainly east of the Mississippi River. But they have turned up in traps in southeastern North Dakota this summer, and the state Agriculture Department is cautioning homeowners and farmers to be alert for the bugs.
"They have a voracious appetite and can defoliate a plant very quickly," Agriculture Commissioner Doug Goehring said.
The half-inch long beetles are metallic green with bronze wing covers. They were first found in the U.S. in 1916 in New Jersey and have since spread into most states east of the Mississippi, causing hundreds of millions of dollars of losses each year, according to the federal Animal and Plant Health Inspection Service.
North Dakota has been trapping Japanese beetles since 1960. The only other time they have been found was in 2001, in Burleigh County.
"This sort of caught us off guard," Goehring said of the findings this summer.
Both Goehring and NDSU entomologist Jan Knodel say the finding could be nothing more than a fluke.
"I don't think they're established yet (in North Dakota)," Knodel said. "I think they were introduced from Minneapolis, came on recent nursery shipments."
Knodel said it is unlikely that beetles are flying long distances from drought-ridden states where there is less green foliage to eat.
"We're hoping this winter we'll have a cold winter and we won't find them next year," she said.
State officials aren't taking any chances, especially as the pests already have established populations in parts of neighboring Minnesota and South Dakota.
In South Dakota, where the beetles for now are a problem only in urban and suburban Sioux Falls, "the population is new and growing," South Dakota State University entomologist Paul Johnson said.
"I would expect them to become at least minor pests in local fields within a few years given their rate of population growth," he said.
Goehring said officials will be monitoring next spring to see if any beetles survive the North Dakota winter.
"We need to stay on top of it," he said.