Steve Osborne, Allen County Agriculture and Natural Resources Extension agent, recently reported damage to alfalfa by the three-cornered alfalfa hopper. These green, wedge-shaped insects jab their piercing-sucking mouthparts into stems, lateral branches, or petioles as they feed on legumes. Plants may become yellow, red, or purple above the injury. Later, the stems may lodge or break.
Three-cornered alfalfa hoppers are probably present in many legumes in late summer but well below damaging levels. Occasionally they are abundant enough to cause noticeable injury in some parts of a field but the injury usually is limited and lodging appears well after the damage was inflicted.
By Lee Townsend, Extension Entomologist