Insect pests can be controlled by treating the pests or their loci with a combination of recombinant virus and organic insecticide. The recombinant virus preferably is a baculovirus. Combinations of recombinant baculovirus with chemical insecticides provide a dose-response in pests, such as insects, that is greater than additive. Preferred treatments of the invention are uses of recombinant baculoviruses that express a foreign protein or toxin, with pyrethroid insecticides. Treatments against pyrethroid resistant pests are especially useful.