A strain of boll weevil, Anthonomus grandis Bobeman, genetically selected for extended postirradiation survival and mating propensity in the laboratory was tested in isolated 1/4 acre field plots near Clinton, Louisiana. The genetically selected strain (RR) and a strain maintained at Mississippi State, MS (ST) were both reared and irradiated in North Dakota (= ST-ND). Males of these strains were compared to those of the ST strain mass-reared and irradiated in Mississippi (= ST-MS). Postirradiation survival and the ability of the RR strain to suppress egg hatch of untreated females over a two week period were not significantly different from that of the ST-ND or the ST-MS strains.