Grape colaspis

The grape colaspis (Colaspis brunnea) is a beetle species within the order Coleoptera and the family Chrysomelidae. Despite its common name, it is a significant pest for various crops, including corn and soybeans, often causing substantial economic losses in North American agricultural systems.

This insect affects a wide variety of plants such as corn, soybeans, strawberries, beans, and grapes. The pest is particularly problematic because it attacks both the vegetative parts of the plant through adult feeding and the root system through the larval stage, causing dual stress to the crops.

The life cycle of Colaspis brunnea typically consists of one generation per year. The insect overwinters as larvae deep within the soil. As temperatures rise in spring, the larvae migrate upward to feed on roots. By early summer, adults emerge to feed on foliage, mate, and deposit eggs back into the soil, completing the cycle.

Adult feeding causes characteristic lacy or shothole damage to leaves, which can reduce the photosynthetic capacity of the plant. Larval damage is often more severe, as they prune root hairs and smaller roots, causing stunting, chlorosis, and in cases of heavy infestation, the total collapse of seedlings.

Management strategies for this pest include:

• Implementing crop rotation to disrupt the life cycle.
• Using soil-applied insecticides or seed treatments.
• Managing weeds in field borders to reduce alternative host availability.
• Monitoring adult population levels during the summer months to time potential foliar applications.

Early detection is critical for successful control. Farmers should pay close attention to areas with poor growth or patches of yellowing plants, as these are often indicators of root damage caused by larvae before the adults are visible on the leaves.