Why are some ladybird beetles considered plant pests?

While most ladybird beetles (family Coccinellidae) are considered highly beneficial because they act as predators that feed on plant-sucking insects like aphids and scale, a small number of species are considered plant pests because they feed directly on vegetation.12

Unlike their carnivorous relatives, these specific coccinellids are herbivorous and can be quite destructive to crops. Notable examples of these plant-feeding species include:2

• The squash beetle (Epilachna borealis)2
• The Mexican bean beetle (E. varivestis)2

These beetles belong to the genus Epilachna and are exceptions within a family otherwise recognized for its role in natural pest control.12