|scientific name Dendroctonus pseudotsugae |
common name Douglas Fir Beetle
Windfall and stumps with a DBH more than 20 cm; also (?) healthy trees during droughts or outbreaks.
Flight period is from early April to early September.
The frons is distinct with fine punctures and granules. The pronotum is finely punctured. The declivity has punctures on the interstriae. The above characters as well as the distribution allow D. pseudotsugae/i> to be distinguished from D. simplex/i>.
This species overwinters as young adults. The young adults will emerge as the first wave of adults between May and June. A second wave consisting of the overwintering larvae and the adults that have already mated will have their flight period between July and August. The females will find an appropriate new host and begin to excavate a gallery from a bark crevice. The male will then join the female to mate. After mating the male may or may not leave the female. Galleries are approximately 12 to 30 cm long and follow the grain of the wood on the inner bark. Oviposition will begin 2 to 3 days after the attack and it is estimated that up to 160 eggs can be found per gallery. Frass is packed to separate the eggs as no egg niches are excavated. The eggs will incubate for between 8 to 24 days. The larvae will then hatch and excavate individual mines for between 19 to 72 days. The larvae then pupate for 5 to 18 days. The young adults that emerge after pupation will then overwinter.
This species is considered a forest pest throughout its range.
This species feeds on Pseudotsuga menziesii (Douglas Fir) and Tsuga heterophylla (Western Hemlock) in Alberta. It will also feed on other fir or larch species outside of Alberta.
This beetle is found in Canada in British Columbia and southwestern Alberta. It is found throughout the western US (Washington, Idaho, Montana, Oregon, Wyoming, California, Utah, Colorado, Arizona and New Mexico). This species has been introduced in China.
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