Attracts adult using an irresistible pheromone and floral lure. Set out in mid-June, 50 ft. upwind of vulnerable plants.  Japanese Beetle Trap lures should be replaced every four to six weeks.Japanese beetles are metallic green and copper-colored, and usually grow to about 1/2" long. They will eat almost any plant, but especially love beans and corn. This beetle's larvae are rarely noticed, but their diet of grass and vegetable roots can reduce crop yields and weaken lawns.