The majority of resistance management programs being advocated today are based on the principle of reduced use of synthetic pyrethroids during early and mid-season. At these times, Heliothis populations are commonly light to moderate, and beneficial insects are frequently present in levels sufficient to suppress Heliothis. This is the time frame in which selective microbial insecticides, particularly in tank mix combinations with an ovicide, have the greatest utility. with the recent development of high concentration liquid formulations of Bacillus thuringiensus, this concept was successfully tested or practiced in selected areas of the U.S. and other cotton producing areas of the world where Lepidoptera are the primary early and mid-season insect pest.