Media Contact: Stephen Bambara

(919) 515-1661

June 17, 1997

HOW TO BANISH RAVENOUS "JEWELS"

At first glance, these backyard invaders in repose are beautiful to behold; iridescent green and metallic gold glimmer in the early summer sun. They seem, at first glance, to resemble jeweled ornaments found in regal necklaces and pendants. But a closer look reveals the damage that these deadly "jewels" are inflicting on the foliage in your yard. Once-lush leaves are transformed into forlorn skeletons as hungry jaws leave nothing but veins and stems in their wake. Your roses are ravaged, your crepe myrtle's murdered and your apple and peach trees are plundered.

These pretty predators are Japanese beetles, and they've turned your yard into a salad bar.

"What makes Japanese beetles so damaging is that they're ravenous and prolific," says Stephen Bambara, an entomologist at North Carolina State University. "All this is complicated by the fact that these insects have encountered so few natural enemies here in the U.S. in the 80 or so years that they've been here. In their native Japan, there are pathogens, tiny wasps and flies that attack the Japanese beetle at various points in its life cycle. Here in the U.S., their major enemy is the human. So far, diligent human intervention is the most effective deterrent. "

Bambara, who is also a specialist in the North Carolina Cooperative Extension Service, says that the beetles -- which are related to the June bug -- were first detected in a plant nursery in New Jersey in 1916. Japanese beetles have since spread to most states east of the Mississippi; they spared the Southwest and the far northern states because they cannot thrive in climates that are too dry or too cold. Scientists are investigating with various biological controls brought over from Japan, but so far none have been able to eliminate the pest or bring it into check.

There are five remedies, though, that can help save your shrubs from these "bugs" -- and their grubs -- but they require early and relentless intervention and some are far more effective than others.

The Bug Cocktail

For homeowners who want to try a more biological approach to help control Japanese beetles, there is a home remedy that can be effective, but it's not for the squeamish. Here it is; gather up as many Japanese beetles as you can find, place them in a blender, add a little water and whir it all up into a "bug cocktail." Pour the resulting mixture into a spray bottle and apply to your plants. In many cases, the Japanese beetles will sort of "take the hint" and avoid yards and gardens that reek of dead comrades. If, as time goes by, you have trouble finding enough "ingredients" to concoct more cocktails, you'll know that this ghoulish gruel is great.

The "Sole" Application

Pick -- or knock -- beetles off plants and squash them (the beetles) with the bottom of your shoe.

Biological Warfare

There is a biological agent that causes milky spore disease, a malady that attacks Japanese beetle larvae that are attached to the roots of grass and other plants. This remedy, which can be expensive and may require your neighbors to treat their own yards as well, has not been proven as worthwhile as other methods of control and eradication.

Chemical Intervention

If you want to use chemical intervention, apply insecticides containing carbaryl ("Sevin") or malathion according to label directions. Use the liquid -- rather than powder form -- because the liquid stays within the intended area. The drawback with some types of insecticides is that they last only from five to seven days and must be re-applied. "Again, it's the diligence that pays off in treating these pests," says Bambara.

Sex Appeal

Those who like to use pheromone traps for Japanese beetles should place the traps as far away from the target plants or trees as possible, says Bambara. Since the traps attract the insects, you don't want them homing in near the very foliage that you're trying to save. For peak effectiveness, the traps should be emptied of dead beetles every one or two days.

"Heavy feeding and defoliation can weaken shrubs and trees, especially the young ones, and make them more vulnerable to diseases and other insects," says Bambara. "If you decide to combat these ‘jewels' that have lost their glitter, start when they first appear in your yard and continue your efforts until they stop munching. Your plants will be healthier and stronger if -- or when -- the beetles return again next year."