Chris Harmeyer didn’t spray his vineyard with insecticide for two days. The next thing he knew, Japanese beetles had defoliated two of his seven acres.
That was two years ago, but Harmeyer, the owner of White Oak Vineyards in Cambridge, Iowa, said Japanese beetles continue to be a problem for him today.
And these beetles are no Fab Four from England.
“They are the most tenacious bug I have ever been around, outside of wasps,” Harmeyer said.
Currently, the beetle is found in 52 of Iowa’s 99 counties, the majority of them in eastern Iowa, said Iowa State University entomology Professor Donald Lewis. The area includes Johnson County.
Lewis said the pest becomes present in June, lasting until August and then its grubs remain in the ground from August until the following June.
“It’s a growing problem,” said Patrick O’Malley, an Iowa State Extension commercial horticulture field specialist. “They’ve been in Iowa City for 10 years, and every year, we’ve seen a little bit more of them.”
Lewis said the insect hasn’t populated the entire state yet because they move slowly, but he expects them to cover the whole state in about a decade or so. The insects are big problem in Johnson County.
Charlie Caldwell, the owner of Black Squirrel Vineyard & Winery, located near Council Bluffs, said the beetles haven’t hit him as hard on his western Iowa farm, but he’s starting to see more and more, which is typical of an infestation.
“Sunny day, you go out there, you shake the bush, and if you hear this freight train go off, that’s a Japanese beetle,” he said.
The beetle feeds on the flowers and fruit of more than 300 different kinds of plants. It enjoys linden trees and roses and especially grape leaves and raspberries.
Iowa State Extension viticulture specialist Mike White said that of the 400 commercial vineyards in the state, roughly 30 will contact him regarding the beetle.
“[The beetle] is a potential for some,” he said. “It’s a crisis for others when the population gets really high.”
Harmeyer said he saw the first signs of the beetles last week, and he hasn’t sprayed for them yet, but he will soon.
“When they start showing up, you have to be prepared for them,” he said.
Harmeyer said for him, the most effective means of killing the bug are pesticides — Sevin being his choice.
Tom Moore, a viticulture technician at the Winery at Kirkwood Community College in Cedar Rapids, is expecting millions of Japanese beetles to invade his vineyard this year, and he, too, uses Sevin.
“If you don’t do something about them with the pesticide, then they will completely eat your vineyard,” he said.
Without these preventative measures, the Japanese beetles would eat all of the leaves off of a vineyard, Harmeyer said.
“They create a lot of havoc, in more ways than one,” he said.