In spring, which insect is a major pest of alfalfa by damaging crowns and stems?

• A. Colorado potato beetle
• B. Stink bugs
• C. Potato leafhopper
• D. Alfalfa weevil

Answer: (D)

The insect described is the alfalfa weevil, a major spring pest of alfalfa because its larvae and adults target the growing points at the crown and young stems. After winter, these weevils become active in spring and feed first on the tips, then on the crown tissue and stems of young alfalfa plants. This feeding can girdle the crown and kill or severely stunt plants, causing stand losses and reduced yield if not managed early. The other insects listed don’t fit this pattern: the Colorado potato beetle specializes in potato, potato leafhopper mainly causes leaf damage (hopper burn) rather than crown/stem injury in alfalfa, and stink bugs are generalist feeders that don’t typically cause crown and stem damage in alfalfa in spring.