People occasionally see small, ornately marked beetles in their yards defoliating shrubs. These insects are a type of leaf beetle known as Calligrapha. This genus of leaf beetles is characterized by having ornate patterns on their wing covers. They are generally yellowish to reddish brown with black and sometimes gold markings. The particular species people are likely to encounter is Calligrapha spiraeae. They are known to defoliate spiraea, ninebark, and Ribes. Adults are commonly seen in July and August.
In most cases, these beetles can be ignored. Healthy, well-established shrubs can tolerate their feeding, even complete defoliation. Don't treat shrubs if they are already mostly defoliated. However, if recently transplanted shrubs or stressed plants are attacked and there is still at least 50% of the leaves remaining, it may be necessary to protect the shrubs from the insects. Any registered residual insecticide, such as permethrin, cyfluthrin, or acephate, should be effective against these beetles. Be sure the product you intend to use is labeled for the plant you wish to treat.
Originally published in Yard and Garden Line News, August 2002