Skip to Main Content
Occurrence of insect and disease pests on young-growth Sitka spruce and western hemlock in southeastern Alaska.Author(s): Susan M. Tait; Charles G. III Shaw; Andris Eglitis
Source: Res. Note PNW-RN-433. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 16 p
Publication Series: Research Note (RN)
Station: Pacific Northwest Research Station
View PDF (810 KB)
DescriptionInsects and diseases were surveyed in 16 even-aged, young-growth stands of Sitka spruce (Picea sitchensis (Bong.) Carr.) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) in southeastern Alaska. Stand ages ranged from 17 to 27 years in nine thinned stands and from 12 to 22 years in seven unthinned stands. All stands appeared healthy. Although some organisms with damage potential were observed, no pests occurred at levels likely to cause damage. Insects recorded on spruce included a Zeiraphera sp. shoot moth (the first record of this insect in southeastern Alaska), a Dioryctria sp. moth, and a Pineus sp. aphid. Fungi that cause spruce diseases included Lophodermium picea (needle cast), Chrysomyxa ledicola (needle rust), and Discocainia treleasei and Heliotium resinicola in cankers. Insects on hemlock included Pseudohylesinus tsugae bark beetles, which occurred more frequently in thinned stands and on trees larger than 3 inches in diameter at breast height, and the adelgid, Aldeges tsugae. Diseases on hemlock included needle rust caused by Pucciniastrum vaccinii and dwarf mistletoe (Arceuthobium tsugense). Sawflies (Neodiprion spp.), geometrid moths (including Melanolophia imitata), blackheaded budworm (Acleris gloverana), and the shoot blight fungus, Sirococcus strobilinus, appeared on both spruce and hemlock. Armillaria sp. occurred in 39 percent of 165 hemlock stumps and 36 percent of 165 spruce stumps following thinning and was more common in hemlock stumps from stands thinned 5-6 years earlier than in those thinned 3-4 years earlier. Fomes annosus was found in only 2 percent of the spruce stumps and in no hemlock stumps.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationTait, Susan M.; Shaw, Charles G. III; Eglitis, Andris. 1985. Occurrence of insect and disease pests on young-growth Sitka spruce and western hemlock in southeastern Alaska. Res. Note PNW-RN-433. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 16 p
Keywordsinsect surveys, diseases (plant), young-growth stands, Sitka spruce, western hemlock, Alaska (southeast)
- Spatial and population characteristics of dwarf mistletoe infected trees in an old-growth Douglas-fir - western hemlock forest.
- The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in southeast Alaska
- Production of wood pellets from Alaska-grown white spruce and hemlock
XML: View XML