Kalamazoo Mi - Japanese beetles are now out in full force

Japanese beetles are beginning to defoliate some types of trees, shrubs and flowers in southern Michigan. On linden trees the beetles feed most heavily on the tops of trees, turning the leaves into lace. They also feed on a wide range of other deciduous trees and shrubs, including roses, linden, sassafras, sycamore, pin oak, Norway maple, Japanese maple, pussy willow, birch, elm, canna lilies, raspberries, grapes, beans, Virginia creeper and flowering fruit trees. Japanese beetles continue feeding and laying eggs throughout July and August. By early September the beetles begin to die and few can be found after October 1. After feeding on leaves and flowers the beetles mate and lay eggs in turfgrass where they become the white grubs that eat turf roots.

Control options to protect susceptible types of trees, shrubs and flowers from Japanese beetle: the insects may be picked off by hand and dropped in a can of soapy water (dispose of them once they’re dead) or you may spray them with Sevin (carbaryl) or Bayer Multi-Insect Killer (cyfluthrin) as soon as they start stripping leaves. Spray again every week to two weeks, until late August, if necessary. The Japanese beetle traps are a great way to find out if you have Japanese beetle, but do little to prevent plant damage. (Dave Smitley, MSU Entomologist)

To obtain more information about home Horticulture issues, call Linda Whitlock, Consumer Horticulture Coordinator at the Kalamazoo County MSU Extension Office at (269) 383-8815 or email her at whitlo13@msu.edu.

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