The objectives undertaken in this study were:
1) to develop means of identifying the immature stages of
the known insect predators and parasites of the Douglas-fir beetle; 2) to investigate the possible distribution,
spatially and/or temporal, of the known insect predators
and parasites in standing trees infested by the Douglas-fir...
The flight behavior of Ips confusus (Lec.) was primarily
studied under field conditions, but augmented with
complementary laboratory studies whenever feasible. The
experiments were mostly conducted in areas of endemic population
levels, but also under epidemic and prairie conditions.
The techniques and devices used in marking, releasing,
attracting, and trapping...
The purpose of this study was to study in some detail
host factors which influence the population dynamics of
bark beetle. The dissertation objectives were to ascertain
the applicability of utilizing osmotic pressure
values and relative turgidity values of phloem tissue as
indicators which reflect upon the physiological profile
of...
Factors considered were phloem moisture, sour-phloem (which
may be furthered by the presence of ample phloem moisture), oleoresin of the host, and the presence of unmated female beetles in
suitable host material.
Levels of phloem moisture present in variously prepared logs
in the field ranged from about 100 to upwards...
Behavioral responses exhibited by the Douglas-fir beetle,
Dendroctonus pseudotsugae Hopkins, to various attractant sources
were investigated under both laboratory and field conditions. Tests
were designed to observe olfactory responses. Results were correlated
and compared with collections from sampling nets and with
emergence patterns. Field data were collected during the flight...
The effect of competition on the brood survival of the Douglas fir
beetle Dendroctonus pseudotsugae Hopkins, in down or windthrown
Douglas-fir Pseudotsuga menziesii (Mirb.) Franco was studied in the
field and the laboratory. The investigation of the role of competition
in the population dynamics of the beetle had four objectives:...
The study (1) describes the life cycle of P. nebulosus,
(2) examines stimuli that may cause the beetles to locate brood
material, and (3) establishes the relationship between moisture
stress in Douglas-fir and colonization by P. nebuZosus.and other
meristem insects.
(1) Development of P. nebulosus goes through the egg stage,...