Pesticide-induced differential mortality between Delia antiqua (MEIGEN) and several other organisms associated with its natural control (Coenosia tigrina (F.), Entomophtora muscae (COHN), and Aphaereta pallipes (SAY)) were evaluated under simulated field conditions. Direct and residual differential mortalities were described for 3 herbicides (Chloro-IPC, nitrofen, and CDAA), 3 fungicides (maneb, chlorothalonil, and copper sulfate), and 1 insecticide (malathion). The recommended field application rates of these chemicals produced high positive differential mortality levels between D. antiqua and some of the natural mortality agents. Chloro-IPC, a preplant and midseason herbicide, induced 100% mortality of A. pallipes over the 3-day residual test period. Modifications in behavioral orientation and death patterns of D. antiqua adults infected with E. muscae were also noted in malathion-treated flies such that subsequent conidial dispersal was highly restricted. none