Asiatic garden beetles will quickly ruin perfect flowers and vegetables by chewing ragged holes in leaves or eating patches of flower petals. Sometimes they will settle into a fruit tree and remove thousands of leaves. Underground, the beetle larvae (curled white grubs) can be serious pests of germinating corn.
In areas where this pest is common, many gardeners monitor populations by placing a pail of soapy water in the garden next to a low-wattage black light. Beetles attracted to the light fall into the pail and drown.
After dark or just before dawn, place cloth sheets or pizza boxes beneath plants that are being damaged, and knock the beetles to the ground for collection. When disturbed, Asiatic garden beetles instinctively drop downward. You also can use a broad bowl of soapy water to collect beetles feeding on individual plants.
Orange hawkweed, an invasive weed from Europe, is a preferred host plant for this pest. If you see numerous white grubs in the soil when you pull up a hawkweed plant, you can assume they are larvae of Asiatic garden beetles.