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Registro Completo |
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Biblioteca(s): |
Embrapa Florestas. |
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Data corrente: |
04/01/1993 |
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Data da última atualização: |
29/07/2025 |
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Autoria: |
SWEENEY, J. D.; MILLER, G. E. |
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Título: |
Distribution of Barbara colfaxiana (Kearfott) (Lepidoptera: Tortricidae) eggs within and among Douglas-fir crowns and methods for estimating egg densities. |
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Ano de publicação: |
1989 |
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Fonte/Imprenta: |
Canadian Entomologist, Ottawa, v. 121, n .7, p. 569-578, 1989. |
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Idioma: |
Inglês |
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Conteúdo: |
The spatial and frequency distributions of eggs of Barbara colfaxiana in Douglas-fir trees and stands (Pseudotsuga menziesii) were determined by dissecting 13 262 conelets collected from 81 trees at 3 sites over 2 years in British Columbia. There were no consistent trends in egg density associated with crown level or aspect. The frequency distribution of eggs per conelet fitted the negative binomial in 3 of 5 site-years but a common k for the negative binomial could not be calculated. R.H. Green's index of aggregation suggested that the egg distribution was significantly aggregated in each site-year. The optimal number of conelets per tree to sample was determined to be 4 in forest stands and 3 in seed orchards. The number of sample trees required for estimating mean egg density with 10% and 20% precision and 90% confidence was calculated for a range of mean egg densities using the method of E. Kuno. The sample sizes required to estimate a control threshold density of 0.6 eggs/conelet with 10% precision and 90% confidence were very large and would be impractical for operational use. Therefore, a sequential sampling plan was developed for use in seed orchards that would classify cone moth egg densities as either above or below a critical density at which 10% seed loss would be expected. |
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Palavras-Chave: |
Agricultural entomology; Biology; Cones; Distribution; Economic thresholds; Mariposa de cone; Pseudotsuga menziessi; Techniques; Tontricidae. |
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Thesaurus Nal: |
Barbara colfaxiana; conifers; ecology; forest pests; insect pests; pests; population density; sampling; seeds; spatial distribution; statistical analysis; trees. |
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Categoria do assunto: |
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Marc: |
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Registro original: |
Embrapa Florestas (CNPF) |
