Lady beetles and parasitic wasps often keep the greenbug below economically important levels. Certain barley varieties are resistant to greenbugs and can help reduce the need for insecticide treatments. Some greenbugs are resistant to some insecticides. Resistant greenbugs are not widespread. If a control failure is experienced, it is unlikely that control will be achieved by retreatment with the same product or a different insecticide from the same chemical family.
Most insecticides currently registered on small grains are from one of two closely related families.
The best way to avoid such problems is to treat greenbug infestations only when it is absolutely necessary, based on greenbug or RWA action thresholds. Ask your local Colorado State University Cooperative Extension county office or other reliable source if these or other products have failed in the area. Key to common wingless aphids on Colorado small grains. 1 Colorado State University Cooperative Extension entomologist and professor, bioagricultural sciences and pest management. Illustrations by T. J. Weissling.