Studies on sex pheromones and biology of the pecan weevil, Curcilio caryae (Coleoptera: Curculionidae), and the sex pheromone of the hickory shuckworm, Cydia caryana (Lepidoptera: Tortricidae)

Scope of study. To monitor and control any insect pest effectively, the behavior of the pest must be understood. Pecan weevil behavior has not been well studied to the extent of developing a new tool for monitoring. The pecan weevil sex pheromone is an effective monitoring tool could allow producers to more effectively determine pecan weevil infestations in the field. Knowledge of mating behavior is need in order to test the pecan weevil pheromone in the laboratory before moving to field evaluations. Confirmation of the pheromone in the field is critical since early release of the pheromone to the public as occurred with the hickory shuckworm pheromone, leads to mistrust of the producers. Evaluation of nut tree fruit was conducted using a Hardee olfactometer to determine pest host preference. Field trials were also conducted on the hickory shuckworm pheromone to determine its usefulness to producers and to determine the number of generational flights that occur in Oklahoma.;Findings and conclusions. Pecan weevil mating behavior in the laboratory is diurnal with peak mating occurred at 14:00-14:59hrs in the afternoon. The pecan weevil male was also found to tap the mesothoracic legs on the lateral margins of the female prior to insertion of the aedeagus. Laboratory experiments found that the pecan weevil females are more attracted to synthetic pecan weevil pheromone than commercial boll weevil pheromone, boll weevil frass, or even live males. Data from the 1995 field trial indicated that synthetic pecan weevil pheromone was more effective in the field that boll weevil pheromone or unbaited control; however, in 1996, field results were inconclusive. Experiments on feeding preference of pecan weevils indicate no differences in male and female response to particular fruit, but there were significant differences in fruit. Pecan weevils prefer pecan and bitternut hickory to shellbark hickory and black walnut. Data also indicates that shellbark hickory is more attractive to weevil than black walnut. The field trial with hickory shuckworm pheromone was more conclusive. There were no differences between pheromone lures, and showed that there were three generational flights of hickory shuckworm in Oklahoma.