Traps best way to deal with beetle problem

Five years ago, I hardly ever saw a Japanese beetle in my garden. Now my garden - and probably yours, too - is overrun each year by these hungry creatures. (In case one or two of you out there don't know this pest, it's a 3/8 of an inch long by a 1/4 inch wide beetle with a metallic green head and copper-colored wings.) Before gobs of beetles on rose blossoms and skeleton remains of grape leaves induce panic, rest assured that we have many approaches available for dealing with this pest.

But first, where do these beetles come from? Japan, of course, where, incidentally, they're not a problem. Most recently, the beetles came from our lawns, emerging from eggs laid last summer that hatched into grubs that fed on grass roots, and wintered over there before undergoing their final metamorphosis. Grubs are C-chaped, white, caterpillar-like creatures. By the end of the month, beetles will start to disappear as they are diverted from feeding to burrowing in the soil to lay eggs for next year's offspring.

One way to deal with the beetles, then, is to kill the grubs. Japanese beetles fly, so you'll have to get your neighbors to kill their grubs, and your neighbor's neighbors, and so on, the larger the area the better. Milky spore is a commercially available disease that kills those grubs and nothing else, which is good, except that, these days, it's less effective than it was in the past, probably because of less effective formulations and insect resistance. Friendly, soil-dwelling nematodes are also sometimes effective and commercially available; the best nematodes for this job are Steinernema glaseri or Heterorhabditis spp, which should be specified on the label.

Japanese beetles like to lay their eggs in lush lawns with moist soil, so if everyone stopped watering their lawns during dry spells, we all would have fewer beetles next year. Don't worry about your lawn turning brown if you forgo watering; the grass will green up when moist weather returns....