BEHAVIORAL MODIFICATIONS AND THEIR IMPLICATIONS FOR COCKROACH RESISTANCE TO TOXIC BAITS

Abstract:
Inter-strain variation of German cockroaches in response to several commercial baits and their potential to develop resistance to the baits was investigated. Late instars were given a choice between the bait and an alternate food source (dog chow). Survivors were saved and choice tests repeated. Tests were done on fourth or fifth generation progeny in selected strains except with Raid Max. Relative attractancyl repellency was estimated on basis of percentage bait consumption (amount of bait consumed divided by total food consumption). The greatest inter-strain variation was with Baygon bait and Raid Max. It was associated with physiological resistance, but a behavioral component also affected the response to Raid Max. Avoidance and physiological resistance increased significantly in one strain following two generations of selection with Raid Max. Baygon bait was repellent to all strains. Low levels of physiological resistance had major effects on bait efficacy. Abamectin baits (Roach Ender and WIT gel) and, in tests with insecticide susceptible strains, Raid Max, were highly attractive. Avoidance was increased in two strains selected with abamectin baits. Strong behavioral resistance developed in strains selected with Stapleton's Magnetic Roach Food. The implications of the above for pest management are discussed.