An insect that causes damage to leaves, flowers, and turf

Japanese beetles feed on the leaves and flowers of many types of trees, shrubs and plants. Linden, birch, apple, rose bushes, grape vines and cotoneaster are most susceptible to Japanese Beetle feeding.  Japanese beetle activity is dramatic and alarming when it is noticed; yet the effects seldom cause serious harm to the health of infested trees or shrubs.

Infested trees require treatment for control
Topical or systemic insecticide treatment can limit the damage from feeding by Japanese beetles.  In recent seasons we have adjusted our treatments to minimize or eliminate off-target exposure of pollinating insects to our treatments.  Current regulations prohibit use of pesticides on flowering trees and shrubs when bees could forage on them.

What to look for
• Adult beetles feeding on the foliage of many trees causing damage that looks like windows in the leaves.
• Extensive feeding damage makes a dull, brown appearance in the crown
• Adults also feed and congregate on flowers of many species,
including roses.

Life Cycle
• Adult beetles lay eggs in July and their larvae feed on grass roots in turf from August through May.
• Larvae emerge from the soil as adults and feed on the leaves and flowers of plants in June and July
• Adult beetles leave a pheromone on attacked leaves that recruit additional beetles to the tree.

Treatment and Prevention
• Place cloth or other barrier around flowers to prevent feeding damage.
• Pick damaged leaves off of small trees to reduce further attacks.
• We cannot treat rose bushes without putting bees and other pollinators at risk. Consider hand picking the beetles into a jar of soapy water to kill them.
• Plant less preferred shrubs and tree species in your landscape.
• Don’t Use Traps – these recruit more Japanese Beetles to your yard because the beetle is attracted to the scent of the plants versus the trap.

Leaf Damage.
Japanese Beetle Feeding.
Japanese Beetle grubs feed on the roots of grass and other groundcover plants.