Impact of Swiss Needle Cast on Postharvest Hydration and Needle Retention of Douglas-Fir Christmas Trees

Plant Disease ◽  
1984 ◽  
Vol 68 (3) ◽  
pp. 192 ◽  
Author(s):  
G. A. Chastagner
Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 773-778 ◽  
Author(s):  
E. M. Hansen ◽  
J. K. Stone ◽  
B. R. Capitano ◽  
P. Rosso ◽  
W. Sutton ◽  
...  

An epidemic of Swiss needle cast, caused by the ascomycete Phaeocryptopus gaeumannii, is causing defoliation and growth reductions in Douglas-fir forest plantations along the Oregon Coast. The area of symptomatic plantations has been monitored annually since 1996 by aerial survey; in spring 1999, 119,500 ha were affected. Pathogen and symptom development have also been monitored on nine permanent plots in stands of differing disease severity. Infection levels and symptom severity are greatest in low elevation plantations close to the coast. In areas of severe disease, trees retain only current year needles. Defoliation is proportional to the number of stomata occluded by pseudothecia of the fungus, with needles being shed when about 50% of stomata are occupied, regardless of needle age. Fungus sporulation and premature needle abscission are greatest on the upper branches of trees. Annual application of fungicides increases needle retention significantly. Tree height and diameter growth and total tree volume are reduced by disease, and tree volume is significantly correlated with needle retention on our plot trees. The epidemic continues to be most severe in Douglas-fir plantations established on sites where Sitka spruce and western hemlock or red alder predominated in earlier times.


2011 ◽  
Vol 41 (10) ◽  
pp. 2064-2076 ◽  
Author(s):  
Douglas A. Maguire ◽  
Douglas B. Mainwaring ◽  
Alan Kanaskie

Swiss needle cast, a foliar disease caused by the Ascomycete Phaeocryptopus gaeumannii (T. Rohde) Petr., continues to afflict Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) in north coastal Oregon. Permanent plots were installed in 1998 to assess growth impacts and monitor disease severity. Gross periodic annual increment was measured for three 2-year growth periods and one 4-year growth period and ranged from 0.37 to 31.74 m3·ha–1·year–1. Foliage retention, defined as the average number of annual needle age classes held by a tree, was also estimated as an index of disease severity. Assuming negligible losses in stands with maximum needle retention (approximately 3.9 years), growth losses in net periodic annual increment reached slightly over 50% in stands with the lowest needle retention (approximately 1 year). Mixed-effects regression models supported a consistent relationship between foliage retention and both gross and net periodic annual increment among the four growth periods. Periodic annual mortality ranged from 0 to 19.12 m3·ha–1·year–1 but was not significantly influenced by Swiss needle cast as measured by average foliage retention. Minimum and maximum foliage retention has fluctuated annually from 1998 to 2008 on the permanent plots, but growth losses at a given level of foliage retention appear to have remained stable. Estimated growth losses are similar to those reported for comparable levels of defoliation by other agents.


Author(s):  
David Montwé ◽  
Bryan Elder ◽  
Peter Socha ◽  
Jessica Wyatt ◽  
David Noshad ◽  
...  

Abstract Substantial growth losses in Douglas-fir can be the result of Swiss needle cast, a foliar disease caused by the fungus Nothophaeocryptopus gaeumannii. Although the disease is native to western North America, it is expected to become increasingly problematic in regions where climates become warmer in winter and wetter in spring, such as in coastal British Columbia (BC), Canada. Previous research suggests that tolerance to this disease is under partial genetic control. We therefore aim to screen for tolerance and resistance to the disease in the tree breeding population of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) in BC. We evaluated if early screening for resistance or tolerance to this disease is possible. We worked with 32 families grown for 18-years on two full-sibling genetic field trial sites representing different climates. We assessed >900 trees for disease signs and symptoms from 2017 to 2019. Needle retention was assessed in the field. In the laboratory, the proportion of stomata occluded with pseudothecia was measured, deoxyribonucleic acid (DNA) was extracted, and the proportion of fungal DNA in the needles was assessed using quantitative polymerase chain reaction. Strong differences were observed among families for needle retention, stomatal occlusion and fungal load. The milder and wetter site closer to the coast was generally more severely affected. Families showed rank changes between the two sites for all response variables. Higher needle retention was correlated with increased tree volume. No correlation was found between the proportion of stomata occluded with pseudothecia, fungal DNA load and needle retention. These results indicate that a more complex pathology is involved in causing needle loss. We conclude that screening for Swiss needle cast tolerance in the coastal BC Douglas-fir breeding population is possible if needle retention can be assessed and that area-specific deployment strategies may be needed given family rank changes in different environments.


2012 ◽  
Vol 61 (1-6) ◽  
pp. 104-115 ◽  
Author(s):  
H. S. Dungey ◽  
C. B. Low ◽  
J. Lee ◽  
M. A. Miller ◽  
K. Fleet ◽  
...  

AbstractGenetic improvement of Douglas-fir in New Zealand was initiated in 1955 with large provenance trials established in the late 1950’s. These trials illustrated that material from the coast of Oregon and California grew faster than other provenances tested. Further collections were made to evaluate provenance and familylevel performance from these two areas, and in 1996 additional trials were established at four low-altitude sites across New Zealand. Genotype×environment (GxE) interaction among these sites was found to be important for diameter at breast height (DBH), less important for stem straightness and malformation and not important for outerwood acoustic velocity (a surrogate for wood stiffness). Heritabilities were low to moderate for all growth traits, and very low for malformation. Heritability for needle cast due to Swiss needle cast, measured as needle retention on the one site where infection was relatively high, was moderate at 0.37, and was likely a major factor creating GxE interactions for growth among sites. The heritability of wood acoustic velocity was moderate to high at individual sites (0.26-0.74) and across sites (0.49). Individual- trait selection revealed the potential for good genetic gains to be made when selecting the top 20 families for diameter growth (an average of 10.7%), straightness (an average of 11.5%) and acoustic velocity (an average of 7.0%). When we examined predicted genetic gains while selecting for needle retention and/or DBH, we found that selecting for needle cast at the affected site did not compromise DBH gains at that site. Selecting for genotypes with low needle cast at the affected site did, however, reduce gains for DBH estimated across all sites. In order to maximise gains across the current Douglas-fir growing estate, a division of growing sites between those known and predicted to be affected by needle cast and those not affected would seem appropriate. This is particularly relevant given recent climate modelling work suggests that Swiss needle cast will become more important in the South Island, and even more destructive in the North Island of New Zealand. We suggest addressing differences in site through the development of separate deployment populations.


2005 ◽  
Vol 35 (2) ◽  
pp. 331-339 ◽  
Author(s):  
G R Johnson ◽  
Amy T Grotta ◽  
Barbara L Gartner ◽  
Geoff Downes

Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity (MOE), modulus of rupture (MOR), microfibril angle (MFA), wood density, latewood proportion, and sapwood moisture content were examined in 20- to 28-year-old trees from 15 stands that were infected with varying intensities of SNC. SNC severity was quantified by measuring needle retention, the number of needle cohorts retained at three crown levels. Correlations between disease severity and wood properties were examined at both the stand and within-stand levels. Trees from heavily infected stands (needle retention <2 years) had higher MOE, wood density, and latewood proportion and lower sapwood moisture content than trees from healthier stands. Breast-height age (BHage) was also correlated with these properties, but age alone did not explain all of the increases. MFA was not associated with SNC severity. Within stands, needle retention was not associated with MOE or MOR. The increase in latewood proportion in diseased stands appears to be the driving factor behind their increase in stiffness (MOE). Ring width decreased with decreased needle retention, and the examined wood properties generally showed stronger correlations with ring width than with needle retention.


1989 ◽  
Vol 19 (2) ◽  
pp. 244-246 ◽  
Author(s):  
J. M. McDermott ◽  
R. A. Robinson

Nine provenances of Douglas-fir, Pseudotsugamenziesii, were examined for the presence of Swiss needle-cast pathogen, Phaeocryptopusgaeumannii, in a plantation at the University of British Columbia Research Forest, Haney, B.C. The provenances were represented in a randomized complete block design. A severe epidemic of Swiss needle cast had persisted in the plantation for a number of years. Fructification of the fungus on more than 75% of the foliage provided an opportunity to assess provenance variation in disease resistance. Analysis of variance demonstrated that there are significant differences among provenances in resistance, as indicated by needle retention, to the Swiss needle-cast pathogen. Linear regression indicated a positive relationship between needle loss and the proportion of the remaining needles with pseudothecia. Provenance variation for needle retention and fructifying needles both correlate strongly with rainfall data from the meteorological station nearest to each provenance origin. This result is consistent with the hypothesis that the provenances of Douglas-fir may have evolved in response to selection pressure imposed by the biological stress of Swiss needle-cast disease.


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