Pennington County preparing to battle the Japanese beetle

Nearly a century ago, long before the Japanese Imperial Navy staged a surprise attack on Pearl Harbor, the Japanese invaded the U.S. mainland. Well, tiny little Japanese beetles did, anyway.

Now, those same pesky insects have silently sneaked across the country and set up a command center near Rapid City in western South Dakota.

“If left uncontrolled, they can take over,” said Scott Guffey, Pennington County’s commander-in-chief in the beetle battle, who already is taking steps to prevent a local infestation. “They can really run rampant if nothing is done.”

Insect lore says the first Japanese beetles arrived in the United States in 1916, but even before then, Japan was inadvertently exporting pests. On Jan. 6, 1910, 2,000 cherry trees arrived in Washington, D.C., a gift of friendship to the people of the United States from the people of Japan. But, to everyone’s dismay and to the embarrassment of the Japanese government, inspectors from the U.S. Department of Agriculture discovered the trees not only were diseased, but also were infested with insects and nematodes.

By Jan. 28, President William Howard Taft had ordered all of the trees burned.

Despite the diplomatic setback, the Japanese in 1912 made amends by sending 3,020 cherry trees of a dozen different varieties to the U.S. capital. Twenty Gyoikos were planted on the grounds of the White House, Yoshinos were planted around the Tidal Basin, and virtually every variety of cherry tree soon graced East Potomac Park.

Now, just as Washington, D.C., concludes the 2015 edition of its annual National Cherry Blossom Festival, weed and pest experts in western South Dakota have issued a battle cry, warning lawn lovers, rose revelers and ornamental plant aficionados that they are under attack by ravenous demons in metallic green and bronze with white hair tufts that extend around their half-inch-long backs.

“There’s no real natural enemy to keep the Japanese beetle in check,” said Guffey, Pennington County weed and pest director, who claims this particular insect may be his toughest foe in 17 years of battle.

To alert the public to the growing menace, the South Dakota Weed & Pest Control Commission recently added the Japanese beetle to Pennington County’s locally declared pest list, its equivalent of the FBI’s Ten Most Wanted.

“The Japanese beetle is considered the single most significant turf grass pest in the United States,” the Pennington County Weed & Pest Board warned in a prepared release. “The Japanese beetle is a serious invasive insect pest that threatens western South Dakota and the western United States. The adult insects feed on flowers, fruits and foliage of more than 300 species of ornamental and agricultural plants.”

According to Guffey, the Japanese beetle first was found in the U.S. in a New Jersey nursery in 1916. It was presumably introduced into the country in soil with plants imported from Japan. It has since spread throughout the eastern U.S. and is now in Minnesota, Iowa, Missouri, Arkansas and every state east of the Mississippi River except Florida and Louisiana, he said.

The South Dakota Department of Agriculture began testing for the beetle in 1987 and, in 2006, the first Japanese beetles were detected in the state’s southeast corner. Since then, the insect has become well-established in five counties along the Interstate 29 corridor in the eastern part of the state, Guffey explained.

When state Department of Agriculture inspectors monitoring shipments of nursery stock from Minnesota realized trees had been delivered to the site of a retirement community under development in 2013 in northwest Rapid City, “They set up traps and found Japanese beetles in significant numbers, certainly enough to be concerned about,” Guffey said.

When the beetles again were detected last year, pest control experts realized they had a reproducing population in the Rapid City area and set about planning a rapid response to the threat, he said.

“The biggest concern in the Rapid City area is the lawns, the turf grass, and also your ornamental plants and trees,” Guffey said. “They’ll defoliate trees and plants, and they can kill them. The larvae are really hard on turf grass and, as you know, we have quite a greenway running through the center of Rapid City.

“If they ever got established there, it would be a nightmare to control,” he added. “I would sure hate to look back 10 years from now, and they are established in Rapid City and say, ‘I wish we would have done something.'”

In its first concerted attack, Pennington County last Saturday spent about $800 to have a commercial applicator treat eight acres near St. Martin’s Village in the northwest area of the city with a larvicide intended to kill the pests, Guffey said. In the next week, he said, inspectors will reset traps, and they hope to find a significant reduction in adult Japanese beetles.

For now, Pennington County is conducting reconnaissance, conserving its resources, and keeping its insecticide dry, Guffey said. But come the battle, he said, troops would be ready.

“The easiest and cheapest pest to control is the one you don’t have,” he said. “Prevention is the most effective and efficient management strategy when dealing with non-native invasive weeds and pests.”