Now is the time of the season to prepare for the devastation that the Japanese Beetles will cause next spring. Look back at the article I wrote concerning grubs in the spring. There is a “beautiful” picture of the grub damage that was prevelent last spring. It may seem odd, but just like you have to plant bulbs in the fall to get spring flowers, you have to think about controlling the beetle/grub population now to prevent damage in the spring. Let’s look at the life cylce of the Japanese beetle. The adults usually emerge in June and July. Their purpose in life at this point is to eat and mate. Unfortunately for us they don’t have a specific plant they go after. They are happy to eat around 300 different types of plants. So controlling the adults is difficult. The females are happy to mate with many different males as well. After the female mates she will burrow into the soil 2-4 inches and lay 1-5 eggs. After laying the eggs she will go back to munching and mating. This cycle continues until she has buried between 40-60 eggs. In 17-25 days the eggs will hatch into a C shaped white grub. The grubs are enjoyed by crows and skunks and unfortunately they will tear up your lawn looking for them. It is easiest to control the grubs at this young stage. Applying a grub control with Merit in it will make the grass roots poisonous to the grubs and kill them.
If the adults are chewing up your garden you can also spray them with an insecticide. You will have to spray on a regular basis because the adults keep emerging all through the summer months. Phermone traps are not recommended because they bring hordes of beetles into your garden. It is better to not trap at all, or give the trap to your neighbor so the beetles visit their garden instead. To identify the beetle look for a beautiful metallic green bug eating your plants. There is only one other beetle that looks like the Japanese beetle and that is the False Japanese Beetle. The way you can tell the difference is to look at the hair tufts along the abdomen. The Japanese Beetle has them making it look like they have 5 white dots on the side of their body.