Asparagus aphid

This is a small, slender aphid about 1/32 to 1/16 inch long. It is green to gray-green in color and is more or less covered with a gray, powdery material. The cornicles are very small and difficult to see without considerable magnification. The winged forms are darker, almost black, in color.
Symptoms: Asparagus aphids feed in the axils of the modified leaves and under bracts. Heavily infested seedlings may form rosettes or shrivel and die. Similar infestations on older plants may cause severe dwarfing. Symptoms of aphid attack include a shortening of the internodes between the whorls of needles which produces a characteristic tufted appearance marked by a blue-gray color. Premature release of buds from the crown during the fern stage of growth can also occur. This can result in plant death if all viable buds are exhausted at the time of fern cutting. Feeding occurs only on the ferns, and aphid colonies have not been found on the marketable spears. In some areas of the U.S., this pest has been described as the most damaging species that feeds on asparagus.