In the U.S. the beetles reproduce without males, which are not found in this country. They may overwinter in any stage, becoming active again in the spring and egg laying occurs from late spring through early fall. The female creates a small chamber by folding over a margin of a leaf and clamping it together, depositing a few eggs in the chamber. When the eggs hatch the larvae drop to the soil and feed on the roots, with densities as high as 150 larvae per square foot and from 3 to 9 inches deep in the soil. There will normally be 1 generation per year. They are known to feed on over 100 varieties of plants, with roses being a preferred host, but also on many other trees, shrubs, and flowering plants.
Control with insecticides is aimed at killing the adult beetles, as the larvae are generally going to be in the soil. Contact insecticides applied to the foliage when adult beetles are present can be helpful.