There is increasing interest in replacing conventional synthetic insecticides with safer and more benign pesticide compounds. Management of two insect pests of alfalfa, the alfalfa weevil, (Hypera postica (Gyllenhal)) and lygus bug (Lygus spp.) using biopesticides was conducted in two Montana locations. Pest and predator densities were monitored during a 2 week period during 2003 and 2004. Treatments included; azadirachtin, a limonoid insect growth regulator; pyriproxyfen, a pyridine contact, stomach poison and insect growth regulator; capsaicin-allyl isothiocyanate, a botanical contact and repellent; bifenthrin, a synthetic pyrethroid standard and an untreated control. Alfalfa weevil larvae and adult populations were reduced in bifenthrin, azadirachtin and pyriproxifen treated plots 5 to 14 days after treatment. Treatments had little effect on lygus bug densities during the study. Nabid spp. populations were reduced by the bifenthrin and increased in the azadirachtin treatment. There was little effect on Orius spp. Predator-prey ratios were determined.