Pine bark beetle

Some of the pests in question included the "pine looper moth, pine beauty, pine moth. Nun moth, saw flies, bark beetles, pine needle cast fungus, pine bluster rust, honey fungus, red rot (Maser, The Redesigned Forest, p. 78). 

Miller, P. R., F. W. Cobb, Jr., and E. Zavarin. Photochemical oxidant injury and bark beetle (Coleoptera Solytidae) infestation of ponderosa pine. III. Effect of injury upon oleoresin composition, phloem carbohydrates, and phloem pH. Hilgardia 39 135-140, 1968. 

The genera] increase in injury in the severe and moderate plots is probably related to the 1974 increase in June-September dose (Figure 12-5). Tree mortality among ponderosa and Jeffrey pines was about the same in 1973 and 1974. The largest mortality was at permanent study plots in the moderate injury eatery. Perhaps the populations in these plots still retain greater numbers of the more susceptible genotypes. In earlier years, tree mortality rates for ponderosa or Je y pines in several stands suffering moderate to severe injury were 8% and 10%, respectively, from 1968 to 1972, 8% from 1969 to 1971, and 24% from 1966 to 1%9. The final cause of death of weakened trees is usually the pine bark beetle. Mortality has not been observed in tree species other than ponderosa and Jeffrey pine. 

FIGURE 12 18 Relationship between degree of oxidant injury to ponderosa pines and bark-beetle attack (left) and numbers of trees killed by western pine beetle, mountain pine beetle, and the two species together (right). Reprinted with permission from Stark and Cobb. ... 

Stark, R. W., and F. W. Cobb, Jr. Smog injury, root diseases, and bark beetle damage in ponderosa pine. Calif. Agric. 23(9) 13-15. 1%9. 

Oxidant injuiy to ponderosa pine predisposes the trees to later invasion by pine bark beetles. Ozone and ozone-sulfur dioxide mixtures may decrease the population of soybean nematodes. Both greater and smaller effects have been noted when herbicides have been used in the presence of high oxidant concentrations. 

As is indicated in Fig. 22-3, the same intermediate cation can yield a variety of end products. For example, pure geranyl diphosphate pinene cyclase catalyzes formation of several other terpenes in addition to a-pinene.89 Another aspect of terpene synthesis is that insects may convert a plant terpene into new compounds for their own use. For example, myrcene, which is present in pine trees, is converted by bark beetles to ipsenol (Fig. 22-3), a compound that acts as an aggregation pheromone.90... 

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. 

It is interesting to note that in the registration process, information concerning the impact on these non-target species, such as the natural enemy community of bark beetles is not required. In both the remedial and preventive modes, the natural enemies are exposed to the insecticides. It has been shown (8) that overall emergence of predators was reduced by 89% and the ratio of natural enemies to the western pine beetle (D. brevicomis LeConte) emergence was reduced by 80% as a result of remedial use of 2% lindane on D. brevicomis. 

Pheromone Disruption and Inhibitors. Pheromones play an important role in the landing and attack behavior of bark beetles (9, 11, 12). Attractants orient flying beetles to a common host tree in high numbers over a relatively short time period. Two techniques have been recently developed to take advantage of the southern pine beetle response to pheromones. 

Seybold S. J., Quilici D. R., Tillman J. A., Vanderwel D., Wood D. L. and Blomquist G. J. (1995) De novo biosynthesis of the aggregation pheromone components ipsenol and ipsdienol by the pine bark beetles Ips paraconfusus Lanier and Ipspini (Say) (Coleoptera Scolytidae). Proc. Natl. Acad. Sci. USA 92, 8393-8397. 

Figure 6.12 Cyclization reactions of acyclic, unbranched and methyl-branched ketones to bicyclic acetals and cyclic alcohols in bark beetles. (A) Mountain pine beetle, Dendroctonus ponderosae formation of exo-brevicomin [(1 F ,5S,7fl)-(+)-7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane] from (Z)-6-nonen-2-one (Vanderwel and Oehlschlager, 1992 Vanderwel ef a/., 1992a) ...

Barkawi L. S. (2002) Biochemical and molecular studies of aggregation pheromones of bark beetles in the genus Dendroctonus (Coleoptera Scolytidae), with special reference to the Jeffrey pine beetle, Dendroctonus jeffreyi Hopkins. PhD thesis. Univ. Nevada, Reno, 193 pp. 

Byers J. A. and Birgersson G. (1990) Pheromone production in a bark beetle independent of myrcene precursor in host pine species. Naturwissenschaften 77, 385-387. 

Lu F. (1999) Origin and endocrine regulation of pheromone biosynthesis in the pine bark beetles, Ips pini (Say) and Ips paraconfusus Lanier (Coleoptera Scolytidae). PhD thesis. Univ. of Reno, Nevada, 152 pp. 

Martin D., Bohlmann J., Gershenzon J., Francke W. and Seybold S. J. (2003) A novel sex-specific and inducible monoterpene synthase activity associated with a pine bark beetle, the pine engraver, Ips pini. Naturwissenschaften 90, 173-179. 

Tillman J. A., Lu F., Donaldson Z., Dwinell S.C., Tittiger C., Hall G. M., Blomquist G. J. and Seybold S. J. (2001) Biochemical and molecular aspects of the regulation of pheromone biosynthesis in pine bark beetles. Presented at Annu. Meet. Int. Soc. Chem. Ecol., 18th, Lake Tahoe. 

Wood D. L. (1962) The attraction created by males of a bark beetle Ips confusus (LeConte) attacking ponderosa pine. Pan. Pac. Entomol. 38, 141-145. 

There is also the possibility that pollutants alter susceptibility of the plant to pathogens (36) or insect attack. Of the latter there is the decreased resistance of ponderosa pine to bark beetle attack caused by ambient oxidant exposure (37). The investigations of others with respect to the effects of fluoride on ponderosa pine indicated that although foliar injury was associated with increased resin exudation pressure, which could be interpreted as an increased capacity of the tree to overcome bark beetle attack, degree of insect infestation was not associated with amount of foliar injury (38). As more is known about pheromones, the botanical investigation of the secondary products of metabolism, such as terpenes and phenolics, may become more important in investigating the mode of action of pollutants in the entire plant. The switch to alternate pathways, while resulting in the same products, may reduce the intermediates needed in biosynthesis and thereby affect the plants resistance to disease or attractiveness to insects. 

Oxidant air pollution is one of several competing mortality factors which acts in all age classes, and it has already been shown to interact synergistically with another mortality factor—the pine bark beetle—to hasten death. Other interactions must be identified and evaluated. A complex predictive computer model will be required to handle such massive amounts of data and eventually quantify the important impacts of oxidant air pollution on this forest ecosystem. 

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