The Japanese Beetle can completely defoliate a tree. In doing so, the tree is at risk because it no longer has a full crop of leaves to absorb sun to gain energy, which can cause the tree to weaken and die over time.
Japanese Beetles are destructive insects, emerging from the ground as full grown adults for a 6 to 8 week period beginning around late June.
Each beetle can live for 30 to 45 days creating more and more damage as they feed.
Although the Linden is the Japanese Beetle’s favorite meal, White Birch, Purple Plum, Maple and certain Crab Apples are also frequented. A wide variety of shrubs and roses will also sustain heavy damage. On trees, they only eat the tissue between the veins of the leaf creating a skeletonized appearance as shown in the photo. Once damaged, the leaves begin falling to the ground.
Just before their life cycle ends, each female lays dozens of eggs in our lawns. The grubs that hatch from these eggs feed on grass roots until the cold Fall weather drives them deep into the soil below the frost line. As the soil warms the following spring, they resume feeding on grass roots. The grubs pupate in the soil and begin emerging in late June as full grown adults repeating the process.