Abstract Speed of action was determined for Siege and Maxforce baits (2.0 and 2.15% hydramethylnon, respectively) against the JWax susceptible strain of the German cockroach. Forty insects were used in the test, 10 each of the following age/sex classifications: 1) adult males; 2) newly mated females; 3) 4th instar nymphs; and 4) 2nd instar nymphs; all insects were newly eclosed (<48 h of eclosion). Cockroaches were housed in 30 X 24 X 10 cm plastic boxes supplied with two water vials (positioned along walls of arena) and two food dispensers (2X2 cm weigh boats positioned in the corners). Arenas were made escape-proof by use of ventilated, friction-fitted lids and an impassable barrier of petrolatum and mineral oil (1:3) on the arena walls. Baits were applied in ca. 50 mg portions within a specially constructed crack and crevice device. These were fashioned from a 1“ by 1” piece of particle board and a 1“ by 1” piece of unpainted plywood, these being separated at a distance of 0.25” by a pine strip glued along one edge. Baits were applied as single 50 mg spherical beads. Siege was applied from the Xactadose Precision Baiting System; Maxforce was applied from the manufacturer’s syringe. Once the baits had been applied in the crack and crevice device, they were stored in lab-cabinets. Here the baits were aged for 0, 3, 7, 10, 14, 28, 56, and 90 d before bioassay. Two bait placement schemes were used: 1) no-choice, where the bait in the device was placed in the opposing corners of the arena; and 2) choice, where supplemental food sources (2.5 g of Wayne™ rodent blox and grape jelly) were placed in the alternate corners of the arena. Cockroaches were released into the arenas and after a 24-h acclimation period, toxic baits and food sources were introduced to the arenas in a random order. Each combination of bait, competition, and aging was replicated three times in a completely randomized design. The speed of kill (LT50, LT95) for each combination of bait, competition, and aging was determined by regression analysis of cumulative, probit mortality against the log 10 of time (d). Further, palatability ratios (PR50, PR95) were determined by comparing the statistics in the regression analysis of the cumulative mortality in the choice bioassay to those in the no-choice bioassay for each combination of bait and aging.