The effects (beneficial or detrimental) of insecticides on the morphology and physiology of crop plants are poorly understood. Plant growth has been shown to be inhibited by some insecticides (Arthur and Arant 1954) and plant yields have been increased by others (Wressell and Driscoll 1964). Wheeler and Bass (1971) reported that phorate, carbofuran, methomyl, and disulfoton, when applied to soybeans, did not affect germination, number of mature pods per plant, or yield. They did report, however, that soybean plants were taller in plots treated with methomyl and carbofuran. The following experiment was conducted in order to clarify some of the findings of Wheeler and Bass.