The Japanese beetles are back in town: Here’s how to protect our roses, other plants

“The Return of the Japanese Beetles” sounds like a horror movie. Unfortunately, these beetles have returned to devour our landscapes for another summer of terror. Once a seldom-seen insect, they are now well established in the Kansas City area. You can expect this frightening feeding frenzy to replay every summer.

The adult Japanese beetle is a shiny metallic green/bronze with white dots, and it feeds on more than 300 plant species. They love roses, grapes and linden trees but feed on green beans, hibiscus and crepe myrtle as well. Few garden plants are exempt from their destruction and appetite.

There is good news and bad news regarding the feeding habits of the Japanese beetle. The good news is they rarely kill the plant. Instead, the foliar feeding causes the plant and flowers to look unsightly. The bad news is that they are difficult to control.

Many gardeners just let them have their way for the four to six-week period they are active. Tolerance is a challenging trait to practice. Instead, gardeners reach for chemical controls to reduce the foliar and flower feeding.

Products labeled for control include Cyfluthrin, Bifenthrin and Cyhalothrin which may last around two weeks. Organic Neem Oil can be used but must be reapplied about every three days. Be aware, these insecticides also have a negative impact on the beneficial insects like bees and butterflies.

An organic, beneficial, insect-friendly option to control Japanese beetle is hand removal. While time consuming and not a fun task, it is effective. Shake off the heebie jeebies, and just knock the beetles into a bucket of soapy water to meet their demise. The ideal time is in the cool of the morning. They are sluggish earlier in the day and become more active as the day gets hotter.

Internet rumors caution about knocking the shiny beetles to the ground and stepping on them. Some believe crushing releases a pheromone scent that will attract more beetles. Research has found that squashing the invaders does not draw more feeders. If it makes you feel victorious to stomp them, go right ahead.

It is true that Japanese beetles are drawn to an area by the use of pheromones. Japanese beetle traps, or lures, are baited with the scent to attract the adults. They fall into the trap, cannot fly out, and are left to die. These traps are available for purchase and effective in attracting the beetles.

The problem with the traps is that they attract more beetles than they catch. Placing a trap in your garden may unknowingly increase feeding on the same plants you are trying to protect. If you want to experiment with a trap, put it as far away from desirable plants as possible. These traps are not recommended for suburban lots.

Japanese beetles have a grub stage, which can can damage lawns. Luckily, grub control treatments rid the lawn of these grubs and reduce damage to the turf. Controlling the grubs in your lawn will have no effect on the number of adults feeding on your plants as they fly in from surrounding areas.

When it comes to the annual arrival and feeding of this destructive pest, the best advice may be to remember the age-old saying: “This too shall pass.” Patience is a virtue we can practice in the garden.