Do Japanese Knotweed Plants Attract Japanese Beetles?
- Japanese beetles cause serious damage to garden plants. Once the beetle lays its eggs in the lawn, the larvae feed on the grass roots, often causing damage to the lawn. Meanwhile, the adult Japanese beetles munch away on the leaves of nearby plants. The beetles are known to feed on more than 300 plant species.
- No friend of gardeners, Japanese knotweed, which grows as a shrub, originally grew in Asia. The introduced plant reaches to more than 10 feet in height with attractive sprays of flowers in the summer. Some states consider the plant a noxious weed since it quickly spreads into dense shrubs that crowd out native vegetation.
- While knotweed offers few benefits to the garden, the plant attracts the Isotecheta aldrichi fly, which feeds on the aphids that infest knotweed. In turn, the fly deposits its eggs on a nearby Japanese beetle. Once the eggs hatch, the maggots enter the beetle's body, quickly killing it, and helping to keep the beetle population down.