Background: Alfalfa is an important crop in this region and in CA with over 1 million acres. There are several critical issues in alfalfa IPM including the use of insecticides to manage Egyptian alfalfa weevil, (Hypera brunnipennis) and improved management of worms. Insecticides used for weevil control in the late winter and early spring are being found in the surface waters, i.e., Sacramento Delta, and are coming under more strict regulations. Aphids in alfalfa are becoming a more critical issue. Starting in 2013, extremely high populations of Blue Alfalfa Aphids (Acyrthosiphon kondoi) developed in alfalfa fields across the state. This species had, previous to this, been under excellent management with a combination of biological, host plant resistance, cultural, and insecticidal approaches.
Examples of Recent and Ongoing Work
- Reduced risk materials including bioinsecticidal products for alfalfa weevil management.
- Treatment thresholds for alfalfa weevil.
- Incidence of biological control for alfalfa weevils and state-wide monitoring of natural controls of alfalfa weevil.
- Revised sampling technique for alfalfa weevil larvae.
- Incidence and timing of blue alfalfa aphid populations.
- Reasons for the upswing in armyworm populations
- Impact of alfalfa production practices on weevil populations
- Effects of GMO alfalfa with improved digestibility traits on arthropod pests