It takes a year for the Japanese Beetle to develop. The majority of time is spent in the grub stage underground. Adults emerge in June and are active through August. Females feed and lay eggs during this time. Grubs hatch in ten days and feed on grass roots and the tiny hair-like feeder roots of shrubs and trees until cold weather sends them deeper into the soil during the winter. They become active again as soon as the soil thaws in early spring. You may notice bare patches in your lawn or holes that are made by raccoons and skunks digging for the grubs.
Applying Milky Spore to the lawn and flower beds over 6 seasons (Spring, Summer and Fall over a two year period) will build up bacteria, killing the grubs. As the grubs die, they produce more bacteria. Milky Spore is guaranteed to last for 10 years in your soil. It will not affect humans, pets, birds, fish or other beneficial insects, ponds, streams or well water.
In the Chicago area, by the end of June the dreaded Japanese Beetle will be hungry and eating almost everything in site. It seems like only evergreens and Maples are safe. Arm yourself now with Annual Tree & Shrub Insect Control. It is a systemic liquid that you mix with water and pour into the soil at the base of your plants. The roots take in the insecticide and it goes up into the leaves. As the beetles eat, they die. Do NOT use on fruit or vegetables, except those listed. Yes, you can and should use this on your roses! You apply this only once a year. This product kills many insects.
We are the only predator of the adult beetle. Traps are effective (yes they draw some from you neighbor's yard) and if we all put them out, we can stop some of the adults from laying eggs. The traps are cheap, buy one for each of your neighbors. 100 beetles will lay 5,000 grubs in the soil in one season! Please use these products and help educate your neighbors.