The pest complex affecting alfalfa includes a variety of insect populations of which one or more may become abundant enough to warrant insecticide treatment. In general, the alfalfa plant can tolerate a significant amount of feeding by a number of different insects before a rescue treatment is economically justified. However, insect pests such as the potato leafhopper can cause significant injury to the alfalfa plant at very low population levels.
Vigilance is needed to accurately determine when treatment is needed.
Table 5 provides a quick reference to chemical insecticides recommended for insect pests on alfalfa. Also listed in this section are specific recommendations regarding formulations and chemicals, with brief notes regarding biology, assessment, and control of specific pests. Quick Reference to Insecticides Recommended for Insect Pests Affecting Alfalfa. Ranges indicate dosage-dependent preharvest limitation. Use is restricted to certified applicators.