Temporal Pattern of Pinewood Nematode Exit from the Insect Vector Monochamus carolinensis

Laboratory-reared Monochamus carolinensis (Olivier) were used to study the temporal pattern of pinewood nematode dauer larval exit from this beetle vector. Exit rates of dauer larvae were determined by comparing the mean number of dauer larvae carried by adult beetles 0, 7, 14, or 21 days after emergence from the log in which they developed. Density of dauer larvae was highest in beetles on the day of their emergence and dropped slowly through the subsequent age classes. The rate of nematode exit was low during the first week (4.5%) and higher during weeks 2 (20.5%) and 3 (13.1%). A total of 38.1% of the initial dauer larvae exited the beetles during the 3-week observation period.