Recurrent outbreak of the Douglas-fir tussock moth in the Malheur National Forest: a case history.

R.R. Mason; D.W. Scott; M.D. Loewen; H.G. Paul

doi:10.2737/PNW-GTR-402

Treesearch

Recurrent outbreak of the Douglas-fir tussock moth in the Malheur National Forest: a case history.

Informally Refereed

Authors:

R.R. Mason, D.W. Scott, M.D. Loewen, H.G. Paul

Year:

1998

Type:

General Technical Report

Station:

Pacific Northwest Research Station

DOI:

https://doi.org/10.2737/PNW-GTR-402

Source:

Gen. Tech. Rep. PNW-GTR-402. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 14 p

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Abstract

Characteristics of an outbreak of the Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough)) in 1991-95 on the Burns Ranger District of the Malheur National Forest (eastern Oregon) are given and compared with an earlier infestation in the same area in 1963-65. Results of monitoring with pheromone traps, evaluating populations by sampling larvae, and predicting trends and defoliation are reported in detail for the latest outbreak. Temporal patterns of each outbreak also are described and compared with the classic behavior of other tussock moth outbreaks. Findings of this analysis, and the recurrent behavior of tussock moth outbreaks in general, reinforce the importance of maintaining a system for detection, evaluation, and prediction in managing Douglas-fir tussock moth populations in the future.

Keywords

Douglas-fir tussock moth, Orgyia pseudotsugata, insect outbreaks, sampling insects, pheromone traps, population monitoring

Citation

Mason, R.R.; Scott, D.W.; Loewen, M.D.; Paul, H.G. 1998. Recurrent outbreak of the Douglas-fir tussock moth in the Malheur National Forest: a case history. Gen. Tech. Rep. PNW-GTR-402. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 14 p