Here's some more information on these bugs:
"The name “flower beetle” is used to describe many different insects. The true flower beetles live outdoors in the garden and flowerbed. They can be destructive to plants and fruit, but they seldom invade homes.
People sometimes confuse flower beetles with the small brown insects that they find in the cereal in the pantry. Scientists use the name “flour beetles for these pantry pests. Flour beetles can be very destructive pests of stored food.
Flower beetles are common in gardens and flowerbeds. Two of the most common flower beetles in the United States are Euphoria sepulcralis (F.) and Protaetia fusca (Herbst). They are scarab beetles in the subfamily Cetoniinae. These are small beetles — about 0.5″ long. There are some Cetoniinae in Africa that reach up to 5″ in length. Many people call them “Goliath beetles”.
The flower beetle E. sepulcralis is found throughout the eastern United States as far north as Illinois and as far west as Texas. It is a dark beetle with a metallic green or bronze sheen. There are white markings on the wing covers. The flower beetle P. fusca is originally from Asia. It has become established in Florida.
Flower beetle larvae live in the soil. They seem to feed on the roots of grass and other plants in the same way as white grubs do. They may also feed on decaying organic material. They change to adults in chambers in the soil. In warm climates, the adult beetles are found throughout the year. The population seems to peak in the summer.
The adult flower beetle normally feeds on pollen. It takes the pollen from flowers on various trees, including apple, orange, and dogwood. It also gets pollen from flowering plants such as daisies and milkweed. It sometimes feeds at cuts on trees where it eats fermenting sap.
The flower beetle can be a destructive pest when it attacks corn or roses. It has also been found attacking fruit trees, mangoes, and avocados. On fruit trees, the beetles cause damage when they destroy the flowers. This reduces the number of fruit that can develop. The beetles attack the kernels of corn while the ears are on the stalks. .
Because they fly and feed in flowers, the adult beetles will be difficult to control. A pest control professional can treat flower beetles in the larva stage while they are still in the soil. "
Looks like the most effective way to control them is using natural enemies of these bugs:
"Natural enemies of adult Protaetia fusca in Australia include the bird Dacelo novaeguineae (Hermann) (kookaburra) and the fungus Aspergillus flavus Link. Threskiornis spinicollis (Jameson), the straw-necked ibis, is an effective larval predator and adult wasps of Scolia verticalis F. have been bred from P. fusca larvae (Simpson, 1990)."