Japanese beetles have emerged in the Quad-City region, settling in for a four- to six-week feeding frenzy on some of our favorite flowers, trees and fruits.

The beetles defoliate many kinds of plants, "skeletonizing" the leaves by eating all but the veins. This does not kill the plant, but it looks bad, and if the plant is defoliated year after year, it could weaken and go into decline. The beetles especially like roses, raspberry bushes and linden trees, but they'll eat more than 300 different types of plants.

Here are some questions and answers about Japanese beetles (JBs, for short).

Q: What can I do?

A: Iowa State University Extension in Ames recommends vigilant hand-picking in the morning and evening.

Scout your yard every day and get out early and late when the beetles aren't very active and either squash them or tap them into a bucket of soapy water to drown them. They die more quickly in water with soap.

This method is 100 percent effective and environmentally safe, and the earlier you get on top of the situation, the better off you'll be because the beetles seem to be attracted to damaged plants and to others of their kind.

If you have a large yard and a lot of plants, this obviously can be a big job.

Keeping your roses clipped during times of peak JB activity also seems to help.

Q: Isn't there some kind of spray I can use?

A: Yes, but remember that most of these are poisons that kill beneficial bugs as well and introduce more chemicals into our environment.

Andy Kay of The Green Thumbers in Davenport recommends a spray containing the active ingredient carbaryl. Carbaryl (also called Sevin) is a nerve poison; beetles pick it up by eating plants that have been sprayed or by being sprayed with it themselves.

Kay recommends spraying every 10-15 days throughout July. "The key is to get out there early and do a couple of sprays," he says. He notes that carbaryl is thick, so you should take the screen out of your sprayer or it will clog up.

ISU/Scott County Extension horticulturist Duane Gissel says to be careful when you spray so you don't kill bees that pollinate plants. Either don't spray plants in bloom or spray early in the evening when pollinators have left for the day.

Another product with a higher relative toxicity is Suspend SC, with the active ingredient deltamethrin, which is a stomach poison, says Alec Schorg of Aunt Rhodie's in the Village of East Davenport. It is mixed with water and sprayed on plants, and it can be expected to last up to three weeks, which is longer than carbaryl, he says.

A nontoxic product called Surround at Home also may help. This product is 95 percent kaoline clay, a naturally occurring mineral that is mixed with water and sprayed on the leaves of plants, coating them with a milky, mildew-looking film. The film masks the plants so the bugs don't come to eat or, if they do, they turn away because eating coated leaves is like eating chalk, Schorg says.

At present, this product is not generally sold in retail stores, but it is available online at gardensalive.com.

Kate Terrell, of Wallace's Garden Center and Greenhouses, Bettendorf, recommends Bonide's Japanese Beetle Killer, which contains pyrethrum, as well as an organic product called Captain Jack's Dead Bug Brew, which contains spinosid, which is formulated from bacteria.

For trees such as lindens, many landscape maintenance workers are reporting good success using systemic insecticides, applied to the soil around the base of the tree at the start of the beetle appearance. The insecticide moves upward and into the leaves and kills the beetles as they feed, ISU Extension says.

Q: Beetles come from grubs, so can I control Japanese beetles by using grub control on my lawn?

A: If you have had a lawn grub problem, then you may want to treat for them.

But just because you have killed grubs doesn't mean you won't have beetles - they can fly in from elsewhere.

Q: What about traps?

A: The general consensus is that traps will attract and kill a lot of beetles - bucketfuls, in fact, but they may draw beetles to your yard that would otherwise go somewhere else.