Ever seen those old western movies and TV shows where the bad guys ride into town and everyone scatters, running inside to lock their doors and windows and hide? The townspeople know there is about to be a shootout and bullets are gonna fly, so they get out the way in hopes of not getting shot.
Over the last 20 years, the annual return of the Japanese beetle around Memorial Day could be described in the same manner. But instead of riding into town and shooting everything up, Japanese beetles fly in and eat up all our plants — they have the potential to literally destroy some plants in a matter of hours.
The last few Japanese beetle seasons have not appeared to be that bad. Surely the beetle yard bags have not caught them all — has spring been too wet for them? Has the yard-destroying, grub-eating armadillos done some good and knocked down the population? Or are we due for another major outbreak?
Insect populations do run in cycles, with high numbers one year or so then low numbers the next year. However, weather could be the true factor in the decreased number of Japanese beetles. Cold winters and dry weather are thought to affect their life cycle. Fluctuation in the population from year-to-year is determined for the most part by how well the larvae survive the prior July and August, and some experts say the larvae do not survive well in dry soil.
Adult Japanese beetles usually begin to emerge from the soil by late May or early June. They are usually a little less than a half-inch long and metallic green with copper-brown wing covers with five tufts of white hairs projecting from under the wing covers on each side. A sixth pair at the tip of the abdomen distinguish Japanese beetles from similar beetles. These tufts of hair appear as white spots when viewed from above.
Adult beetles feed on at least 300 species of plants, including roses, other flowers and ornamentals, fruit trees, grapes and even poison ivy. They prefer plants in the sun and usually attack in groups, feeding on the upper surface of leaves, which results in a skeletonized appearance of damaged leaves.
Japanese beetles can be controlled non-chemically and chemically:
NON-CHEMICAL: Hand collecting beetles may not be the most effective methods of control, but can be used with smaller populations. Simply drop beetles into a solution of soapy water where they will drown. A hand-held vacuum cleaner can also be used to remove beetles. The presence of beetles tends to attract more beetles making their removal more critical.
Avoid using traps. Traps attract more beetles to the area, many of which do not make it to the traps, doing more harm than good in most home landscapes.
CHEMICAL: There are many insecticides labeled for use against adult Japanese beetles including cyfluthrin, bifenthrin, deltamethrin, lambda cyhalothrin, esfenvalerate, permethrin and carbaryl. For botanical alternatives try Neem, Pyola, insecticidal soap, extracts of garlic, hot pepper or orange peels and companion plantings.
As in any good western movie, the good guys must win. So drum up some courage and get out there and fight. Grab your weapons of choice and protect your resident plants from those invading beetles. Otherwise, there won't be a happy ending.
For help on other home and garden questions, contact your local county Extension office or visit us online at aces.edu.
Shane Harris is an extension agent for the Alabama Cooperative Extension System.