Dispersal and development of the striped ambrosia beetle trypodendron lineatum (oliv.) in industrial sorting and storage areas

Ambrosia beetles, in particular the striped ambrosia beetle Trypodendron lineatum (Olivier.) [Coleoptera: Scolytidae] cause serious degrade to logs harvested in British Columbia. Losses to the Coastal forest industry have been estimated at $120 million per annum. Although 75% of the damage occurs in the forest, 25% occurs while logs are at sorting and storage areas. Populations of ambrosia beetles are spread in logs transported into these areas. Industrial sites become contaminated when beetles egress stored logs and fly to the forest margin to overwinter. These individuals comprise the spring flight the following year and will attack any susceptible stored logs at that time. Mass trapping beetles is an accepted component of integrated pest management around industrial sites. Traps baited with lineatin, cL-pinene and ethanol are commonly used. A Latin square experiment was conducted to test, these components singly, and in combination to elucidate which component or combination of components are best to trap “sister flight” beetles. Results demonstrated that c-pinene and ethanol did not significantly enhance trapping performance and that lineatin is the only significant trap bait for trapping “sister flight” beetles. Lineatin-baited traps located in the Foreshore Park area of the Pacific Spirit Park in Vancouver, were used to trap 1993 sister flight beetles. The same traps were re-baited in 1994 to monitor the mass flight. There was a positive correlation of mass attack catches with sister flight trap catches. Temperature related heat sum model experiments of T lineatum development were conducted at the University of British Columbia in Vancouver. Beetles were inoculated into log bolts left to develop in controlled conditions at 18, 20, 25 and 30 °C, under ambient conditions at the U.B.C. South Campus. A threshold temperature of 12.34 °C was derived and used in the calculation of accumulated heat sum. Sister flight activity was indicated by presence of empty niches after 65 days or 324 degree days. Internal log temperatures were monitored at the South Campus. High mortality precluded brood development in the top and west quadrants of the log where temperatures commonly exceeded 35 °C. Brood development and survivorship were greater in the bottom and eastern quadrants of the log. It was recommended that lineatin alone is sufficient for trapping sister flight beetles. Additional lineatin-baited traps should be used to develop a database to derive a predictive model to determine mass flight numbers from sister flight trap catches to help focus future mass trapping operations. The threshold temperature of 12.34 °C could be used to derive universal model of T lineatum development. Accumulated heat sum of 324 units could be used to predict sister flight. Key Words: ambrosia beetle; degree-day; development threshold; dry-land sorts; heat sum; mass trapping; semiochemicals.Forestry, Faculty ofGraduat