Oklahoma Alfalfa
Oklahoma Cooperative Extension Service
Oklahoma Agricultural Experiment Station

Spotted alfalfa aphids can be distinguished from other aphid species by the presence of several rows of black spots along their backs. These spots are not easily seen with the naked eye, therefore, some magnification may be required. The aphid also has a general yellowish color, unlike the other species which are green or bluish-green.  

Prolonged feeding by spotted alfalfa aphids causes leaves to curl, yellow, die, and drop. Death of the leaves, and ultimately the plant, is due to the injection of a toxin by the aphid. Infestations generally start in localized spots across a field. These spots may first appear yellowish in color but can eventually turn almost white.  

An integrated program for alfalfa aphids involves using several facets of integrated management. These include: planting resistant varieties, biological, cultural, and chemical control practices. 

 On established stands, that may be suffering from drought, late in the season, with no immediate end in sight, simply cutting the hay may not control the aphids completely. This is particularly true if aphids around the edges of fields and in adjacent fields remain uncontrolled and dry conditions persist. Spot spraying of affected areas, however, may be an alternative to whole field treatments. Spot treatments versus whole field application of insecticides may allow for lower costs, preservation of natural enemies, and time for a "possible" rain, before harvest.