M. S.

This research concerns the effects that harborage limitation and habitat isolation have on German cockroach control in urban housing apartments. Standard Mason jar traps were used to survey cockroach populations, trap cockroaches for marking and population census, and detect cockroaches that moved from the original capture sites. Focus apartments (ie. apartments with large cockroach populations) were located and used for the two studies. Five focus apartments were used for the harborage limitation study. All harborage and harborage access in the kitchen and bathroom areas were sealed in three treatment apartments. These areas were not sealed in the two control apartments. Eight focus apartments were used for the habitat isolation study. Three treatment apartments had all accessways (holes and cracks) between the focus and the adjacent apartments sealed. Five control apartments were not sealed. Cockroaches in the three treatment apartments were captured, marked and released at the point of capture. Harborage limitation focus apartments were sprayed with 0. 5% chlorpyrifos in water and habitat isolation focus apartments were sprayed with a 0.25% synergized pyrethrin aerosol. Percentage control for the harborage limitation study was determined and no significant differences (P<0.1%) between treatment and control apartments were found. Percentage movement for the habitat isolation study was determined and no significant differences (P<0. 1%) between treatments and controls were noted. Neither harborage limitation nor habitat isolation would be recommended as a cockroach control technique unless they are used in concert with other control techniques. / Master of Science

M.S.

A quantitative and qualitative study of the behavioral effects of an insecticide on various life stages of the German cockroach, Blattella germanica (L.), was conducted. Comparisons between a susceptible laboratory strain (VPI) and a resistant field strain (BP) were made to examine the relationship between physiological resistance and behavioral resistance. The effects of vapors from a formulation of 1% propoxur in oil were compared with vapors from a mineral oil control. Vapors from the control had little effect on cockroach behavior. Adult males, adult females, and middle instars were repelled from aquaria containing the insecticide vapors. Early instars sought shelter in the pores of water sponges. No differences in behavior due to reproductive state were observed as females with oothecae and females without oothecae were equally repelled. Responses by adult males included increased movement, antennal grooming, and tarsal grooming. Electroantennogram studies showed that the vapors of the propoxur formulation were detected by the antennae. Adults of the susceptible VPI strain responded more strongly to the insecticide vapors, relative to the controls, than did adults of the resistant BP strain. The negative correlation between physiological resistance and behavioral responses was not due to the development of behavioral resistance. Rather the resistance mechanism of the BP strain was probably responsible for inhibiting the behavioral response of that strain. Responses to the propoxur insecticide may have been compounded by solvents in the formulation, but differences between the two strains were probably due to the propoxur. The oil base had no effect on cockroach behavior. That wet sponges provided safe harborage for the early instars indicates the importance of even short range dispersal. Also, the use of repellent barriers to exclude cockroaches from sensitive areas may become less effective if physiological resistance in cockroach populations is accompanied by decreased avoidance responses. Knowledge of the levels of physiological resistance must be supplemented by an understanding of the behavioral characteristics of insect populations for the successful development of pest control programs. / Ph. D.