Japanese Beetles are devastating pests that feed on nearly 300 different species of landscape plants, usually starting at the top of the plant and working their way downward. A single beetle is usually not a cause for concern, but a large group can cause considerable damage to your plants. Adult beetles will chew the tissue between veins of foliage, giving your plants a hollow, unsightly appearance and making them more susceptible to other diseases.
You can identify Japanese Beetles by their hard, copper colored wing covers. Measuring nearly half an inch in length, these beetles will also display small white tufts under the wing covers on each side, with an additional pair at the tip of the abdomen.
When possible, we always stress natural solutions to insect problems. Unfortunately, the hard body of the Japanese Beetle make them unattractive to most predators such as birds. There are a few species of parasitic flies that have shown the ability to control the beetle (especially here in the Northeast) by laying eggs that attach to the back of the beetles, but since this treatment method can take time to develop, this strategy is generally best for small infestations that will allow the larvae time to hatch while damage levels remain low.
Another alternative for low levels of activity is hand collecting. Since the presence of beetles on a plant attracts more beetles, by removing beetles daily by hand from a plant you can stop the proliferation of these pests. The easiest way to remove beetles from small plants is to shake the plants early in the morning (about 7 a.m.) when temperatures are low and the beetles are sluggish. The beetles may be killed by shaking them into a bucket of soapy water.
Japanese Beetle traps attract the beetles with two types of baits. One mimics the scent of female beetles and is highly attractive to males. The other bait is a sweet-smelling food-type lure that attracts both sexes. This combination of ingredients is such a powerful attractant that traps can draw in thousands of beetles in a day.
Since these traps can often be too effective and end up drawing even more beetles to the area, strategic site placement is critical to the success of this method. Place your traps away from your landscape on the outskirts of your property in an attempt to not only catch these critters, but also to lead them away from your plants in general.
If a problem is more severe and natural methods of collecting or trapping beetles simply won't work, an approved insecticide is usually the next course of action. Since garden environments and the level of the problem dictate the best chemical treatment, we recommend that you contact us here at Estabrook's and speak with one of our garden professionals about the best treatment method.