Go for the spray or dunk when fighting Japanese beetles

Q. There is a metallic green-colored beetle decimating the leaves of my Queen of the Prairie plant in my native plant garden. Several times I found four or five beetles on each flower; I shook them all into a bag and destroyed the bag. Now the flowers are loaded with beetles again. I think they are Japanese Beetles. Last year I put a Japanese beetle trap in my yard but I still had many beetles that chewed up my roses late in the summer. How can I rid my yard of these pests and save my roses this year?A. From your description it sounds as if you have an infestation of Japanese Beetles. In addition to being metallic green in color, they have copper-colored wings and are about one-half inch long. The adults are not very picky and will eat more than 250 kinds of plants. A large population can kill plants very quickly.#160; The beetles emerge from the grub stage in turf grass in early July, the same time you would put grub control on your lawn (if you choose to use a chemical control for grubs.) They probably emerged in June this year because of the warm spring we had.As you found from your experience with traps, they may entice beetles to your yard from neighboring areas. Don't bother buying traps.To keep down the beetle population it is also recommended that homeowners not water their lawns in July because the female beetles seem to prefer lush, moist turf to lay eggs for the next generation next summer.An organic way to destroy the beetles is to shake them off the leaves and flowers into a jar of soapy water to keep them from crawling out. Knocking them off the leaves/flowers into a jar of rubbing alcohol will also kill them. If you wish to spray them use a product that contains carbaryl, cyfluthrin or a pyrethroid. These chemicals usually work for about two weeks. After that you need to retreat your plants. Make sure you carefully follow the directions on the chemical container. Now is a good time to check your roses for beetles and control them before your plants suffer damage.Q. Our Brussels sprout plants are about 24 inches now. They have damage on the leafs (at the edges) that seems to be caused by some insect appetites, and at the middle of the leafs also. I suspected mite evidence. We have been using a commercial insect spray from Home Depot. I have considered looking early in the morning (2 a.m.) but have not yet done so. Your suggestions would be appreciated.A. Chances are cabbageworms are eating your Brussels sprouts. There are several kinds of cabbageworms that can find their way on Brussels sprouts, as well as cabbage, broccoli, collards, kale, kohlrabi, and other cole crops grown in Illinois.If allowed to become numerous, these sluggish, velvety-green worms can completely defoliate plants eventually eating their way into cabbage heads. In spring, you may spot white or brown butterflies depositing yellow or yellowish-white eggs on the underside of leaves of cabbage and related crops. Once the eggs are hatched, the cabbageworm larvae begin feeding on foliage. The safest way to control these pests is to check your plants frequently for cabbageworms, especially if you have seen the butterflies nearby. Handpick and destroy any worms you find. If you have a serious infestation, purchase Bacillus Thuringiensis (Bt) from your garden center and apply it according to the directions. Bt is a bacterium that occurs naturally in the soil, and acts as an insecticide by producing proteins that react in the gut of some insects, paralyzing their digestive systems. The insects stop eating and quickly starve.The kurstaki strain of Bt is especially useful for eliminating cabbageworms. Because the bacteria must be eaten by the insect to be effective, good spray coverage is essential. You should avoid breathing the powder or spray when applying Bt to your plants. Because Bt kurstaki will kill most any type of caterpillar, use it sparingly if you want to attract butterflies to your garden.bull; Provided by Mary Boldan and Donna Siemro, University of Illinois Extension Master Gardeners. Send questions to Ask a Master Gardener, c/o Friendship Park Conservatory, 395 W. Algonquin Road, Des Plaines, IL 60016, (847) 298-3502 or via e-mail to cookcountymg@sbcglobal.net.