Life Sciences Commons^™

Emergence And Overwintering Brood Of Douglas-Fir Beetle Seven Years After The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Judith E. Pasek

Judith E Pasek

Emergence patterns and population levels of Douglas-fir beetles (DFB), Dendroctonus pseudotsugae Hopkins, in the seventh year of infestation following the Clover Mist Fire were evaluated on the Clarks Fork Ranger District of the Shoshone National Forest. Adult emergence in 1995 returned to a single peak beginning in mid-June, about a week later than normal likely due to cold, wet spring weather. Adults of both the '93-'94 and '94-'95 generations emerged, demonstrating for the second year in a row that DFB can extend its life cycle up to two years. Almost half of the total emergence of the '93-'94 generation was …

Emergence And Overwintering Brood Of Douglas-Fir Beetle Six Years After The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Judith E. Pasek, Willis C. Schaupp Jr

Judith E Pasek

Two emergence peaks were evident for adult Douglas-fir beetles (DFB), Dendroctonus pseudotsugae Hopkins, collected from caged brood trees in 1994. The June peak resembled emergence patterns observed in previous years; however, an August peak was detected for the first time since monitoring of the outbreak began. The second peak likely resulted from delayed development of brood of the '93-'94 generation that largely overwintered as larvae. A portion of the '92-'93 generation also emerged in 1994, confirming that DFB can extend its life cycle to two years under certain conditions. The '93-'94 generation apparently also has developed an extended life cycle, …

Emergence And Overwintering Brood Of Douglas-Fir Beetle Five Years After The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Willis C. Schaupp Jr, Judith E. Pasek

Judith E Pasek

The emergence of adult Douglas-fir beetles (DFB), Dendroctonus pseudotsugae Hopkins, from caged brood trees in 1993, occurred from May to September, with a peak in mid- to late June. The 1993 emergence pattern is very similar to that observed in 1990 and 1992. In late fall 1993, live DFB adults were found under the bark of trees from which emergence was presumed to have been complete, because the trees had been attacked during summer of 1992. For the '92-'93 DFB generation, emerging adults were far fewer than overwintering brood, suggesting poor winter survival and/or a shift to a 2-year life …

Populations Of Douglas-Fir Beetle In Green Trees Three Years After The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Judith Pasek, Willis Schaupp

Judith E Pasek

Brood densities of Douglas-fir beetle (DFB), Dendroctonus pseudotsugae Hopkins, in green trees adjoining areas burned by the 1988 Clover Mist Fire varied by site, but averaged 8 per 36 sq. in. for bark samples at all sites examined during November 1991. Brood densities were much reduced from 1990 levels, but were similar to densities found in blackened trees in fall 1989. The reduction from 1990 levels was attributed to heavy winter mortality of brood caused by prolonged extreme cold temperatures. Most brood in fall 1991 samples was present in the callow adult stage, similar to 1989 samples, and in contrast …

Populations Of Douglas-Fir Beetle In Scorched And Green Trees 2 Years Following The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Judith E. Pasek

Judith E Pasek

In 1990, Douglas-fir beetle (DFB), Dedroctonus pseudotsugae Hopkins spread from Douglas-firs blackened by the 1988 Clover Mist Fire to partially scorched and green trees on the Clarks Fork Ranger District, Shoshone National Forest in northwestern Wyoming. Adult DFB began emerging in early May and peaked during June. Scorched trees were attacked first and green trees were selected generally after mid-June. A mean of 20 DFB emerged per 36 sq. in. of heavily-infested bark surface.

Total brood production in fall bark samples taken at 5-7 ft. was high, averaging 28 DFB per 36 sq. in., and represents a 1.5- to 2-fold …

Douglas-Fir Beetle Infestation Following The Clover Mist Fire On The Clarks Fork Ranger District, Shoshone National Forest, Wyoming, Judith Pasek

Judith E Pasek

In 1989, Douglas-fir beetle (DFB), Dendroctonus pseudotsugae Hopkins, was detected on the Clarks Fork Ranger District in large-diameter Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, trees blackened by the 1988 Clover Mist Fire. At Cathedral Cliffs and Squaw Creek, respectively, 22% and 32% of charred Douglas-firs greater than 10 in. DBH were infested; approximately 9 and 16 Douglas-fir trees per acre were infested, respectively. Although half the bark samples (6 in. by 6 in.) from infested trees contained no DFB brood, average brood production was high -- 9 and 7 callow adults per sample, respectively, at Cathedral Cliffs and Squaw Creek. Approximately …