Using Japanese Beetle Traps effectively

While disdain for Japanese beetles is universal, opinions differ on the best way to battle them. Options include pesticides, hand-picking them off plants, or trapping. Japanese beetle traps use a lure consisting of natural floral attractants and the beetle's sex pheromone to lure both males and femals to the trap. Beetles fly into the yellow plastic panels and are stunned on impact, then fall into the attached bag.

These lure traps can be an effective method to control Japanese beetle adults, according to an expert on the subject. Dr. Michael Klein was a research entomologist at the USDA's Agricultural Research Service (ARS) lab for horticultural research in Wooster, Ohio from 1969 until his retirement in 2004. Japanese beetles were his specialty throughout his 35 years there.

At the USDA, Klein was an advisor for the Animal and Plant Health Inspection (APHIS) team that is responsible for monitoring infestations in the eastern U.S. and preventing the infestations of the Japanese beetle from moving westward. The serious threat to agriculture posed by the beetle makes this ongoing mission essential.

To keep the beetles from hitching a ride from Cleveland to California, APHIS uses traps as a first line of defense to catch them at various airports around the country. Klein himself routinely uses traps each year to protect plants and trees in his own yard and garden. "Lure traps provide a visible means of combating a Japanese beetle problem without having a negative effect on the environment," he says.

Klein acknowledges two major fears about traps, and the facts that dispel them:

Fear #1: Traps lure Japanese beetles from miles around.

The facts: Most attractants lure beetles from no more than 100 to 200 yards, he says. Beetles, however, are strong fliers and can travel several miles, touching down at random intervals to see what's available for a meal. So the traps only lure beetles that are already in flight near the yard. Klein suggests, however, that problems could occur if using traps near the edge of a golf course or large turf area.

Fear #2: Traps make the problem worse by luring more beetles than they catch.

The facts: Incorrect trap placement can lead to this conclusion, Klein says. If a trap is placed next to a rose bush or other favorite beetle food, a large number of beetles can be lured to that area and some may stop at roses rather than the trap. 

Dr. Klein offers these tips for using Japanese Beetle Traps effectively:

Enlist your neighbors to battle the beetles with you.

Traps can be effective in your yard alone, but if you can get those bordering your yard to set traps along with you, the beetle numbers will be greatly reduced.

Trap placement is critical.

Many people may misguidedly place the traps next to ornamental plants, because that's where the beetles are present and causing the damage. Traps should instead be used about 30 feed from desired foliage, to lure the beetles away. It is preferable to place them next to a non-flowering tree or shrub, such as a pine tree or boxwood, which is not attractive to the beetles.