Major Outbreaks of the Douglas-fir Tussock Moth in Oregon and California PDF Download
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Author: Boyd E. Wickman
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 24
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Book Description
Case histories of five tussock moth outbreaks that occurred in California and Oregon between 1935 and 1965 are discussed. Information is given on the size and duration of the outbreaks, the presence of natural control agents and the damage caused. Most of the outbreaks were eventually treated with DDT. However, enough information was available from untreated portions to show the probable trend of natural events in the absence of direct control. Repeated patterns observed in each of the outbreaks enabled certain generalizations to be made about natural population behavior and tree impact. All infestations followed a 3-year cycle with inconspicuous to minimal defoliation the first year, severe foliage loss the second year, and ultimate collapse of the population by the end of the third year. The most severe tree damage occurred in the second year. Additional loss of foliage before population collapse in the third year was usually of minor importance in terms of total impact. Although other natural factors were involved, a virus disease appeared to be the principal cause of insect mortality during collapse.
Author: Boyd E. Wickman
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 24
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Book Description
Case histories of five tussock moth outbreaks that occurred in California and Oregon between 1935 and 1965 are discussed. Information is given on the size and duration of the outbreaks, the presence of natural control agents and the damage caused. Most of the outbreaks were eventually treated with DDT. However, enough information was available from untreated portions to show the probable trend of natural events in the absence of direct control. Repeated patterns observed in each of the outbreaks enabled certain generalizations to be made about natural population behavior and tree impact. All infestations followed a 3-year cycle with inconspicuous to minimal defoliation the first year, severe foliage loss the second year, and ultimate collapse of the population by the end of the third year. The most severe tree damage occurred in the second year. Additional loss of foliage before population collapse in the third year was usually of minor importance in terms of total impact. Although other natural factors were involved, a virus disease appeared to be the principal cause of insect mortality during collapse.
Author: Boyd E. Wickman
Publisher:
ISBN:
Category :
Languages : en
Pages : 35
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Book Description
Author: Boyd E. Wickman
Publisher:
ISBN:
Category : Douglas-fir tussock moth
Languages : en
Pages : 30
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Book Description
Tree damage occurring immediately after an outbreak of Douglas-fir tussock moth, Orgyia Pseudotsugata McD., and stand conditions 10 years later are described. Because of increased radial growth and ingrowth in the 10-year postoutbreak period, good evidence indicates that tree damage caused by the tussock moth may not be as severe in the overall stand dynamics as previously pictured. The insect probably plays a key role as a phytophagous regulator of primary production in some second-growth white fir stands in California and elsewhere.
Author: J. J. Colbert
Publisher:
ISBN:
Category : Douglas-fir tussock moth
Languages : en
Pages : 92
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Author:
Publisher:
ISBN:
Category : Douglas fir tussock moth
Languages : en
Pages : 20
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Book Description
Author: Robert W. Campbell
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 176
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Book Description
This annotated bibliography includes references to 338 papers. Each deals in some way with either the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), or a related species. Specifically, 210 publications and 82 unpublished documents make some reference, at least, to the Douglas-fir tussock moth; 55 are concerned with other species in the same genus. The subject matter in each paper has been indexed to at least one general topic (General, Taxonomy, Biology, Host Relationships, Outbreaks, Control, Related Material). Most of these general topics have been subdivided into more specific headings. For example, Host Relationships includes separate categories for white fir, grand fir, and Douglas-fir. A complete listing of the references in each general and specific category is presented in the index.
Author: Robert W. Campbell
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 360
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Book Description
Author: Expanded Douglas-fir Tussock Moth Research and Development Program
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 28
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 252
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Book Description
Author: Boyd E. Wickman
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 20
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Book Description