Associations between Swiss Needle Cast Severity and Foliar Nutrients in Young-Growth Douglas-Fir in Coastal Western Oregon and Southwest Washington, USA

Abstract Swiss needle cast (SNC) is a foliage disease of Douglas-fir (Pseudotsuga menziesii) caused by Nothophaeocryptopus gaeumannii, an ascomycete fungus (Mycosphaerellaceae) that causes tree growth reductions in the Pacific Northwest. The epidemiology of the fungus is generally well known, but th...

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Published inForest science Vol. 65; no. 5; pp. 537 - 542
Main Authors Lan, Yung-Hsiang, Shaw, David C, Ritóková, Gabriela, Hatten, Jeff A
Format Journal Article
LanguageEnglish
Published Bethesda Oxford University Press 01.10.2019
Subjects
Aluminum
Calcium
Carbon
Epidemiology
Foliage
Forests
Fungi
Landscape
Magnesium
Manganese
Needlecast
Nitrogen
Nutrients
Nutrition
Pine needles
Plant diseases
Plantations
Pseudotsuga menziesii
Statistical analysis
Statistical methods
Studies
Trends
Oregon
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Summary:Abstract Swiss needle cast (SNC) is a foliage disease of Douglas-fir (Pseudotsuga menziesii) caused by Nothophaeocryptopus gaeumannii, an ascomycete fungus (Mycosphaerellaceae) that causes tree growth reductions in the Pacific Northwest. The epidemiology of the fungus is generally well known, but the relations between disease expression and foliar nutrition are unclear. In this study, we used data from the Swiss Needle Cast Cooperative research and monitoring plot network in western Oregon and SW Washington to assess associations between SNC severity, carbon, and nine foliage nutrients (nitrogen, Na, K, P, Ca, Mg, Mn, Al, S). Foliage samples were collected from midcrown of selected Douglas-firs from each plot. SNC severity was determined on 2-year-old needles by multiplying disease incidence and fungal reproductive (pseudothecia) density. Disease severity and nutrient relations were determined using linear mixed models. SNC severity showed statistically significant positive trends with concentrations of carbon, nitrogen, Na, K, and S, no relation with concentrations of Ca, Mg, or Al, and slightly negative trends that were not significant for P and Mn. This is the first such analysis of associations between a conifer foliage disease and foliage nutrients across a landscape; subsequently, there is little published literature on how or why these nutrients may interact with disease.
ISSN:0015-749X
1938-3738
DOI:10.1093/forsci/fxz022