Questions have come to me as to how to prevent next summer’s Japanese Beetle attack. Kirsten in Cedar Springs, asked specifically about her grape vines. I visited a vineyard in Pennsylvania last summer and they planted rose bushes at the ends of the rows of grape vines. The rose plants were to attract the Japanese beetles to this preferred food and they also sprayed the plants with an insecticide. My Ortho book recommends treating infested grape vines or other food crops with Malathion 50 Plus Insect Spray or Home Orchard Spray.
Japanese beetles have three different stages to their life cycle: eggs, grub, and the adult beetle. If you want to take preventative measures for next summer, attack the stage of the Japanese beetle when it is a grub. In the fall, apply Milky Spore Disease (or another similar product) to your lawn to control the following year’s grubs. The following year, begin spraying ornamental plants with Malathion or Diazinon as the adults emerge, about the same time as Queen Anne’s lace is blooming. Controls may have to be repeated, because new beetles continue to emerge from the soil for about 6 weeks during the summer. Before spraying, make sure that your plant is listed on the product label.
