Pine beetle control

Is of serious concern. The role of chemical communication, in relation to proposed control tactics, of predators and bark beetles will be discussed. Emphasis will be on Thanaslmus dublus (F.) (Coleoptera Clerldae) and Medetera blstrlata Parent (Dlptera Dollchopodldae) which are primary predators of the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera Scolytidae). 

It is the intent of this paper to explore the various control tactics that are being suggested in the management of bark beetles in the forest system with specific attention given to the potential impact on the predator population. Similar arguments could be extended to other bark beetle mortality agents such as the parasite community. Primary examples and control tactics discussed will be drawn from our experience with the southern pine beetle, I). frontalis, a major pest in the southeastern U.S., along with other bark beetles in North America. 

Cut and Leave. This method was first recommended by the Texas Forest Service for controlling small southern pine beetle spots (10-15 infested trees) that could not be salvaged (5). As the treatment implies, trees are felled with the tops directed into the infested area rather than random felling. Mortality to the bark beetles is enhanced by the increased subcortical temperature resulting from direct exposure of the bark to the sun s rays and the inability of the immature stages to move to more protected areas, i.e. the under-surface of the felled trees. 

Table I. Mixture of treatment strategies used in the 1982 Dillon, Colorado, IPM project to control mountain pine beetle...

CgHnOj, Mr 142.20 oil, bp. 99-100 C (15.99 kPa), [a]o -55.5 (diethyl ether). F. is one of the aggregation pheromones of bark beetles of the genus Dendroc-tonus. This attractant is used to promote an effective colonization of a tree first chosen as nesting site by one insect by controlling an optimal ratio of the sexes. Males of D. brevicomis have pure (lS)-(-)-F., the pheromone of D. frontalis (Southern Pine Beetle) is an... 

Wood, D. L., and 33 collaborators Integrated pest management of the western pine beetle. Research approach and principal results. In C. B. Huffaker, Ed., New Technology of Pest Control. New York J. Wiley. In press. 

Chatelain, M. P. and J. A. Schenk, Evaluation of frontalin and exo-brevicomin as kairomones to control mountain pine beetle (Coleoptera Scolytidae) in lodgepole pine. Environ. Entomol. 13 1666-1674, 1984. 

TILLMAN, J.A., LU, F., STAEHLE, L., DONALDSON, Z DWINELL, S.C., TITTIGER, C., HALL, G.M., STORER, A.J., BLOMQUIST, G.J., SEYBOLD, S.J., Juvenile hormone regulates de novo isoprenoid aggregation pheromone biosynthesis in pine bark beetles, Ips spp. (Coleoptera Scolytidae), through transcriptional control of HMG-CoA reductase, J. Chem. Ecol, 2004,30, 2335-2358. 

Conifers exhibit resistance to bark beetle attack and fungal invasion because of an Induced synthesis and flow of secondary resin which contains high levels of volatile monoterpenes. Monoterpene olefin synthases (geranyl pyrophosphate cyclases) were found in higher levels in fungus-infected lodgepole pine seedlings than in uninfected controls. 

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