Figure 1. Dogbane beetle adult. Courtesy: Adam Varenhorst.
Every summer we get asked about a very shiny, iridescent, green beetle (Figure 1). This showy insect is the dogbane beetle. The scientific name for dogbane beetles is Chrysochus auratus, auratus meaning “golden.” This is a fitting name as the beetles are shiny with iridescent green and bronze or gold on their abdomens. Dogbane beetles can be found in several crops including corn, soybean, and alfalfa. However, they are never observed feeding on these plants, so their presence in crops raises concerns about what they’re up to.
The primary hosts for dogbane beetles are spreading dogbane and dogbane (also referred to as: Indian hemp, hemp dogbane, prairie dogbane). In addition, dogbane beetles have also been observed in association with milkweed plants. Both of their primary hosts are poisonous, which makes the dogbane beetle unique in that it is able to feed on them. The presence of dogbane beetles in crops is usually an indicator that one of its weedy hosts is nearby. Because the dogbane beetle is a specialist herbivore, no management recommendations exist as it does not cause injury to crops or garden plants.