Japanese beetles may be beautiful on the outside, but they are destructive to more than 300 species of plants, from turfgrass to roses, grapes and hops.
“The immature beetle larvae, or white grubs, primarily attack the roots of grass crops from turf to corn, but also may attack the underground plant parts of many vegetable crops such as potatoes, sweet potatoes and more,” said Thomas Kuhar, an entomologist at Virginia Tech. “The adult beetles can be equally damaging to other crops such as roses, fruit trees, grape leaves and many vegetable and ornamental plants especially those flowering.”
The Japanese beetle is an invasive species.
“It’s been established in Virginia for many decades, and it is the most important pest of turfgrass,” said Kuhar.
For homeowners looking to control Japanese beetles on plants, products are available including traps, insecticides, neem oil and more.
“None of the natural insecticide products work very well against Japanese beetles in my experience, although they can help with other pests like aphids,” said Kuhar. “The Japanese beetle bags or traps contain a potent combination lure that draws beetles to the trap. However, putting them near your garden can make things worse by drawing beetles in the neighborhood to your location.
“The most effective control is synthetic insecticides that have beetles on the label,” he said. “These are often pyrethroid type insecticides. You may need multiple applications during the heavy infestation period in the summer.”