About ten years ago my neighborhood was overrun by them. They were eating almost everything. Some bushes and small trees we had planted were covered with them. And they bite. My neighbors both had some nice mature hedges in full bloom that they just loved to eat. The three of us got to work trying to eradicate them and save our greenery but it was a losing battle. Think we did more damage to ourselves using the watered down nerve agent we were using to kill them with. Made me dizzy every time I used the stuff.
Seemed about the time we just about thought we had them whooped they came back with a vengeance. Worse than before. They finally killed just about everything green with leaves on it we had planted. The hedges were all dead as were our bushes and small trees.
We all finally gave up and yanked out what was left of what they liked eating and replaced it with pines, ferns and some other stuff that they won't eat.
The beetles won. It wasn't worth the fight. Wasn't even close. Take this advice from someone with some first hand experience.
Don
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http://en.wikipedia.org/wiki/Japanese_beetleJapanese beetle
The beetle species Popillia japonica is commonly known as the Japanese beetle. It is about 15 millimetres (0.6 in) long and 10 millimetres (0.4 in) wide, with iridescent copper-colored elytra and green thorax and head. It is not very destructive in Japan, where it is controlled by natural predators, but in America it is a serious pest of about 200 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, and others.
It is a clumsy flier, dropping several centimeters when it hits a wall. Japanese beetle traps therefore consist of a pair of crossed walls with a bag underneath, and are baited with floral scent, pheromone, or both. However, studies done at the University of Kentucky suggest traps attract more beetles than they actually trap, thus causing more damage along the flight path of the beetles and in the vicinity of the trap than may have occurred if the trap were not present.
These insects damage plants by skeletonizing the foliage, that is, consuming only the leaf material between the veins.