Egyptian alfalfa weevil

Adult Egyptian alfalfa weevils (Hypera brunneipennis) are light brown with dark brown and grey markings down their backs and are about 0.2 inches long. Adult weevils emerge from a summer resting state called aestivation in late fall or winter and begin to migrate to alfalfa fields to feed, mate and lay eggs. The female chews a hole in the stem then inserts her eggs into the center of the stem. Smooth, shiny, yellow eggs are laid in living or dead stems three to six inches above the soil surface or in plant debris on the ground. Eggs hatch in five to ten days. The legless larvae are initially tiny, yellowish green in color and reach a length of 0.25 inch when fully grown. Mature larvae are pale or light green with a thin white stripe down the center of their back and have a dark brown to black head.
Damage: Egyptian alfalfa weevil feeds on alfalfa plant terminals on the first growth after winter. Adult feeding seldom causes significant damage to alfalfa but results in characteristic linear scars on stems. Weevil larvae damage alfalfa by feeding on terminal buds and leaves first and gradually moving down the plant. First and second instar larvae feed on young developing leaves. Third and fourth instar larvae cause the most damage by feeding on interveinal alfalfa leaf tissue, skeletonizing, bronzing, and subsequently defoliating plants. Defoliation reduces alfalfa tonnage and quality, reduces the photosynthetic capacity of the plant, and the damage to regrowth buds can stunt growth and kill alfalfa stems. Weevil damage is often most severe under windrows lying in the field for several days because harvesting moves weevil larvae into a concentrated area under cut hay where they feed on new growth. Typically, the alfalfa weevil can cause damage to the first and occasionally to second and third hay cuttings.