A typical garden attracts hundreds of different species of insects, from beetles and caterpillars to bees, nematodes and moths. Only a few of these insects are pests, and many of the pests are only a problem during a specific part of their life cycle. The vast majority of the insects are "good bugs": predators, pollinators and parasites. The trick is knowing which ones cause damage and when, and learning ways to minimize that damage. 

Japanese Beetle: (Size=1/2 inch) Where: Leaves, flowers, and fruits of fruit trees (apple,  cherry, plum), vegetables (beans), flowers (roses),  ornamentals (apple family); east of the Mississippi 

Controls: Handpicking, milky spore, neem, nematodes, pyrethrins

Still primarily a pest of the eastern U.S., they turn up west of the Rockies from time to time. They're a problem for gardeners for their appetite for a wide variety of plants: Adults feed on just about every kind of flower or vegetable, sometimes in disturbingly large crowds. They chew out the leaf tissue between the veins, leaving a lacy skeleton. Prior to pupating, the white, 1-inch long, C-shaped grubs live in the soil and feed on the roots of most all plants. Grubs are often a problem in lawns. Bug Mugs provided by NationalGardening.com, the online publisher of the National Gardening Association.  Photography by Clemson University Department of Entomology, Cooperative Extension Service 
 

Cucumber Beetle: (Size= 1/4 to 1/2 inch)  Don't be confused by the two different forms of this pest. The striped form is shown above. It's cousin features a dozen black spots. But whether spotted or striped, both are the same size and the same, greenish yellow color, and both dine on a wide variety of cucumber family vegetables as well as various ornamentals such as roses and dahlias. Another well known family member is the corn root worm. They are more dangerous to their cucumber family hosts than many pests because they transmit deadly diseases mosaic and bacterial wilts. The adults over winter in weeds and plant debris. They emerge in spring after the last frost and enter gardens once the growing season is underway. You may first notice them inside squash flowers. They lay orange eggs at the base of host plants; white larva with legs and brown heads chew on roots. Short, northern seasons allow just one generation a year. In the south and mild west, two or more generations are typical. 
Controls: Look for varieties of cucumbers and squash that are resistant to these pests. Cover young plants with floating row covers. Knock, shake, or hand pick beetles off plants and out of flowers, and clean up in the fall to reduce the number of over wintering adults. Dust plants and flowers with insecticides containing pyrethrins. Photography by USDA

Colorado Potato Beetle (Size= 1/3 inch) If you see in your garden a small yellow beetle with black stripes over its wings and black spots just behind its head, say hello to the Colorado potato beetle. The humpbacked larva is equally distinctive: red with a row of black spots along each side. For years it lived quietly in Colorado feeding on weedy potato relatives. But at some point after the potato was well established in North America, its ancestors learned a new trick. It's been the bane of potato growing gardeners ever since. Potatoes are its first love, but this beetle will eagerly consume leaves of potato relatives eggplant, ground cherry, peppers, tomato, and tomatillo.  Colorado potato beetle prefer cold winters. While found as far west as Arizona, Nevada, western Oregon and western Washington, it is by far more common on the East Coast as far south as Virginia, then from there to the north west through Wyoming. The adult beetles over winter in the soil, emerging in the spring to lay clusters of yellow eggs on leaf undersides. There are one to three generations per year, depending on the part of the country.

Controls: Bt, handpicking, neem, early planting, pyrethrins, row covers. A thick organic mulch makes it hard for emerging beetles to reach plants in spring. Surveillance and hand picking remains among the gardener's best defenses. Examine plants while holding container of soapy water to dispose of any you find. Natural enemies include birds, spined soldier bugs, and parasitic nematodes. Spray Potato Beetle Beater, which is Bacillus thuringiensis tenebrionis (also known as San Diego strain), while larva are small to manage major outbreaks. Photography by USDA. Bug photos and information above courtesy of  Gardener's Supply Company
 
 

More Bugs  To learn more about the following bugs...... Aphid, Apple Maggot, Box Elder Bug, Bronze Birch Borer, Cabbage Worm, Carpenter Ant, Flying Ants, Carpet Beetle, Cucumber Beetle, Earwig, Eastern Tent Caterpillar, European Pine Saw Fly, Gypsy Moth, Horn worm, Japanese Beetle, Centipede, Millipede, Pantry Pests, Peach Tree Borer, Slug, Squash Bug, Squash Vine Borer, Annual White Grub.