Shrubs are important as browse and cover for game animals and songbirds in the desert-shrub and chaparral plant communities in the Great Basin (Plummer, 1968). They also play a major role in soil binding and watershed maintenance (Colby and Weissert, 1975). Therefore, an understanding of the agents which affect the health and survival of the shrubs is important. Insects-have a great impact on the health and reproductive capacity of shrubs. Pollinators, defoliators, borers, etc. must be studied and known for proper management.

Thesis (M. Ag. Sci.)--University of Adelaide, Dept. of Entomology, 1966. / Includes bibliographical references.

No description available.

No description available.

Beetles of Trypophloeus populi attacked green bark of unhealthy aspen (Populus tremuloides) and hastened the death of the tree. Beetles of Procryphalus mucronatus favored dead bark and were of little significance in the death of the aspen. These two beetle species were distinguished from each other by their primary galleries, eggs, larvae, larval mines, and mating behavior. In T. populi, there were three larval instars and one to one and one-half generations per year; only larvae overwintered, and the eggs of the first generation were present by mid-July. In P. mucronatus, there were two larval instars and one and one-half to two generations per year; both larvae and adults overwintered, and the first eggs of the new season were present by late May.

4 pp. / Revised / This paper provides evidence of the infestation caused by pine bark beetles in Arizona. It provides information about their life history, and how to prevent and control them.

Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "August 2007." Includes bibliographical references. Online version available on the World Wide Web.

The pine engraver beetles (~ spp.:Coleoptera:Scolytidae) may be serious pests depending on certain prerequisite conditions. In their secondary or "normal" role they breed in slash and damaged, dying, and dead trees. The broods emerging from these sources normally attack similar material. When such material is scarce due to cessation of cutting operations in mid-season or when conditions are especially favorable for brood development, an excess of beetles is often produced which, due to the lack of more suitable material, attack healthy trees. Repeated attacks cause these trees to succumb and die. When normally healthy trees are weakened by fire, flood, defoliation, drought, stagnation, etc., then they become more acceptable host material for successful engraver attacks. When the production of a very large number of beetles in "normal" breeding material coincides with physiological stress in "healthy" trees, then population explosions can occur. When large numbers of beetles and low host vigor do not coincide, spot kills cornnon1y occur. According to Thatcher (32), spot kills, although not conspicuous, add up to large volumes of timber loss each year. / Ph. D.

Includes bibliographical references

My work concentrates on feeding behavior of overwintering diapausing and post {--} diapausing bark beetles and developmental treshold. This is done either biochemically by measuring the enzymatic activity in the midgut and by assessing the feeding status from the size and consistence of the food bolus in the gut. Detailed knowledge of feeding behaviour and development treshold may help to predict the overwintering success of local populations with all the consequencies for spring dispersal and reproduction.