Abstract The behavior of adult Colorado potato beetles (Leptinotarsa decemlineata) in the presence of Beauveria bassiana sporulating on cadavers was studied to determine the likelihood of disease infection as beetles emerge from the soil and colonize host plants. In 2001, the movement of single adult Colorado potato beetles was monitored in arenas containing infective cadavers in differing spatial patterns between four potato plants. In 2002, a similar design was used, but was under the more natural conditions of a potato field. In both experiments, direction, time, and directness of beetle travel was not significantly affected by the presence or absence of infective cadavers, showing no avoidance of these cadavers by adult Colorado potato beetles. The likelihood that emerging adults would contact infective cadavers on the soil surface was quantified at different cadaver densities. A curvilinear relationship (y = 4.8313x0.4459) best describes the frequency of encounters of adults as a factor of increasing...