Relationships between catches in flight and emergence traps of the mountain pine beetle, Dendroctonus ponderosae Hopk. (Col.: Scolytidae)

Daily emergence of the mountain pine beetle from lodgepole pine trees was monitored in the field by using caged bolts and by counting emergence holes on standing trees. Flying mountain pine beetles, pine engraver beetles and Pityogenes plagiatus knechteli (Swaine) were captured daily in two types of barrier traps. Daily totals of emergence holes and emergence into cages were moderately correlated with daily captures by both types of barrier traps. A simple model of daily emergence was developed based on estimates of brood density, daily proportions of brood adults, and daily proportions of brood adults ready to emerge. Daily catches of pine engravers and P. plagiatus knechteli were highly intercorrelated, but correlations with catches of mountain pine beetle were low for both species. The results are discussed in relation to beetle emergence and flight behaviour

Patterns of landing of spruce beetles, Dendroctonus rufipennis (Coleoptera: Scolytidae), on baited lethal trap trees

The distribution of spruce beetles (Dendroctonus rufipennis [Kirby]) landing on lethal trap trees was studied in each of 2 years. A wire basket and sticky boards on each tree were used to trap beetles. Significantly more beetles landed on the north side of the boles than on the other three aspects. The density of beetles that landed increased sharply to about 1.6-2.4 m above ground and then decreased. A three- parameter empirical model was used to describe the relationship. On average, about 4 of all the beetles that landed did so below the maximum height of insecticide treatment (4 m). The proportion of beetles from the lower 4 m of the bole that were trapped in the wire baskets ranged from 11% to 57% and averaged 33%. High correlations between numbers of beetles trapped in wire baskets at the paired trap trees each year, and between beetles trapped in wire baskets and on corresponding sticky boards showed that catches in the baskets were good indicators of the total numbers of beetles that landed on trap trees.Relative heat accumulation in the stand in degree-hours above a base temperature of 13.3°C during the day was a good indicator of the relative numbers of beetles that landed on the sticky boards. On typical days, beetles began to land on trap trees in midmorning: landings peaked between 1500 hours and 1600 hours and ceased by 2000 hours

Mortality of spruce beetle broods in bolts submerged in water

Six weeks of continuous submersion in water of spruce bolts containing larvae and young adults of the spruce beetle resulted in complete mortality. We estimated that 22 days of continuous submersion would be required to kill 50% of the brood. Brood development ceased in the submerged bolts even though water temperature, which increased from 13.3°C to 17.8°C during the experiments, was well above the larval development threshold (6.1°C)

Using explosives to destroy mountain pine beetle broods in lodgepole pine trees

The effectiveness of explosives for the destruction of mountain pine beetles in individual lodgepole pine trees was investigated. Two types of detonating cord, and various placements, were tested on infested bolts and trees, and a plastic explosive was tested on bolts. Explosives killed broods directly, and indirectly by habitat disruption. Direct effects extended about 9 cm from the explosion and mortality was inversely related to distance. Indirect effects via extensive loosening and shedding of bark caused far greater mortality than direct effects. On trees, summer and fall treatment was much more effective than spring treatment, regardless of cord placement. Fall treatment using 10 g/m detonating cord helically wrapped onto the boles at 10, 20 and 30 cm spacings caused 100%, 98% and 70% mortality of broods respectively. Generally, vertical placement of the cord into grooves cut through the bark caused more bark disruption and therefore, more brood destruction than did helically wrapped cord placed on the surface

Field techniques for rearing and marking mountain pine beetle for use in dispersal studies

Mountain pine beetles, Dendroctonus ponderosae, were marked with fluorescent (DayGlo) powders in vacuum chambers and on powder-covered brood trees in the field for use in release-recapture studies of dispersal behaviour. A large wall tent was used as a field insectary to accelerate late stages of development of large numbers of beetles in naturally infested bolts of lodgepole pine. Up to 28% of the marked beetles which flew were recovered from lethal trap trees. Beetles self-marked on powdered brood trees were captured in barrier traps in predicted proportions