Impact of root-rot pathogens on forest succession in unmanaged Pinus mugo stands in the Central Alps

2006 ◽  
Vol 36 (10) ◽  
pp. 2666-2674 ◽  
Author(s):  
M Bendel ◽  
F Kienast ◽  
D Rigling ◽  
H Bugmann

In the mountain pine (Pinus mugo subsp. uncinata (DC.) Domin) forests of the Swiss National Park in the Central Alps, disease centers associated with the root-rot fungi Heterobasidion annosum (Fr.) Bref. and Armillaria spp. are characteristic elements. We assessed the impact of these pathogens on forest dynamics by studying transects running across disease centers into the adjacent forest. Overall, mountain pine was the most abundant regenerating tree species and accounted for 84% of all seedlings (<20 cm high) and 93% of all saplings (20–130 cm high), whereas Swiss stone pine (Pinus cembra L.) was less frequent (15% seedlings : 7% saplings). The density of mountain pine seedlings did not differ significantly between the disease centers and the adjacent forest, whereas mountain pine saplings were more frequent within the disease centers, indicating that growth from the seedling to the sapling stage was favoured in disease centers. There was significantly more dead wood and a greater diversity of plant species in the disease centers than in the adjacent forest. The results suggest that root-rot fungi slow down succession towards stands with a higher proportion of P. cembra by causing premature mortality of mountain pines and creating disease centers with dense mountain pine regeneration.

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1289
Author(s):  
Tuula Piri ◽  
Eeva J. Vainio ◽  
Heikki Nuorteva ◽  
Jarkko Hantula

This study provides new information on the infection biology and pathogenicity of an important root-rot fungus, Heterobasidion annosum sensu stricto (Fr.) Bref., through a detailed examination of the vegetative spread of clonal individuals and their capacity to produce fruiting bodies on young pine seedlings. The seedlings were planted in a clear-cutting area (c. 1.2 ha in size) after a pine generation that showed slight external symptoms of Heterobasidion root rot. The first dead seedlings were found five years after planting and during a nine-year monitoring period; nearly 600 seedlings were killed by H. annosum s.s. in 48 individual disease centers. Based on pairing tests of 482 isolates, 117 different H. annosum s.s. genotypes were identified. On average, 2.9 genotypes occurred in a single disease center. The extensive secondary spread of genotypes within root systems (up to 48 pine seedlings infected by the same genotype) resulted in annually expanding disease centers. In addition, more than half of the seedlings killed by H. annosum s.s. produced perennial fruiting bodies thus providing air-borne inoculum. The risk of spore infection should be taken into account in any type of cutting operation in young pine stands. Moreover, new control measures directed towards the secondary spread of H. annosum s.s. in pine regeneration are urgently needed in order to maintain the productivity of the pine forest on infested sites.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Farid Abd-El-Kareem ◽  
Ibrahim E. Elshahawy ◽  
Mahfouz M. M. Abd-Elgawad

Abstract Background Black root rot of strawberry plants caused by Rhizoctonia solani, Fusarium solani, and Pythium sp. is a serious disease in Egypt. Biocontrol agents have frequently proved to possess paramount and safe tools against many diseases. The impact of soil treatments with 3 Bacillus pumilus isolates on black root rot disease of strawberry plants caused by R. solani, F., and Pythium sp. under laboratory and field conditions was examined herein on the commonly used ‘Festival’ strawberry cultivar. To increase the bacterial adhesion and distribution on the roots, each seedling was dipped in bacterial cell suspension at 1 × 108 colony-forming units/ml of each separate bacterial isolate for 30 min then mixed with 5% Arabic gum. Results The tested B. pumilus isolates significantly reduced the growth area of these 3 fungi. The two bacterial isolates Nos. 2 and 3 reduced the growth area by more than 85.2, 83.6, and 89.0% for R. solani, F. solani, and Pythium sp., respectively. Likewise, the 3 bacterial isolates significantly (P ≤ 0.05) inhibited the disease under field conditions. Isolates Nos. 2 and 3 suppressed the disease incidence by 64.4 and 68.9% and disease severity by 65.3 and 67.3%, respectively. The fungicide Actamyl had effect similar to that of the 2 isolates. B. pumilus isolates significantly enhanced growth parameters and yields of strawberry plants; isolates Nos. 2 and 3 raised the yield by 66.7 and 73.3%, respectively. Conclusions Bacillus pumilus isolates could effectively manage the black rot disease in strawberry herein. Due to the significant impact of the root rot disease on strawberry yield, B. pumilus should be further tested to manage the disease on strawberry on large scale in Egypt.


Open Heart ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. e000943 ◽  
Author(s):  
Leopold Ndemnge Aminde ◽  
Linda J Cobiac ◽  
J Lennert Veerman

ObjectiveTo assess the potential impact of reduction in salt intake on the burden of cardiovascular disease (CVD) and premature mortality in Cameroon.MethodsUsing a multicohort proportional multistate life table model with Markov process, we modelled the impact of WHO’s recommended 30% relative reduction in population-wide sodium intake on the CVD burden for Cameroonian adults alive in 2016. Deterministic and probabilistic sensitivity analyses were conducted and used to quantify uncertainty.ResultsOver the lifetime, incidence is predicted to decrease by 5.2% (95% uncertainty interval (UI) 4.6 to 5.7) for ischaemic heart disease (IHD), 6.6% (95% UI 5.9 to 7.4) for haemorrhagic strokes, 4.8% (95% UI 4.2 to 5.4) for ischaemic strokes and 12.9% (95% UI 12.4 to 13.5) for hypertensive heart disease (HHD). Mortality over the lifetime is projected to reduce by 5.1% (95% UI 4.5 to 5.6) for IHD, by 6.9% (95% UI 6.1 to 7.7) for haemorrhagic stroke, by 4.5% (95% UI 4.0 to 5.1) for ischaemic stroke and by 13.3% (95% UI 12.9 to 13.7) for HHD. About 776 400 (95% UI 712 600 to 841 200) health-adjusted life years could be gained, and life expectancy might increase by 0.23 years and 0.20 years for men and women, respectively. A projected 16.8% change (reduction) between 2016 and 2030 in probability of premature mortality due to CVD would occur if population salt reduction recommended by WHO is attained.ConclusionAchieving the 30% reduction in sodium intake recommended by WHO could considerably decrease the burden of CVD. Targeting blood pressure via decreasing population salt intake could translate in significant reductions in premature CVD mortality in Cameroon by 2030.


2004 ◽  
Vol 34 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Vaidotas Lygis ◽  
Rimvydas Vasiliauskas ◽  
Jan Stenlid

Persistence of the root rot pathogen Heterobasidion annosum (Fr.) Bref. s.s. on infested areas and its transfer to a forest regeneration was studied in three forest sites in eastern Lithuania. The sites represented H. annosum disease centres in Pinus sylvestris L. stands, which were clear-felled and replanted with Betula pendula Roth 25 years prior to our study. Fungal isolation from trees and stumps on each site was performed on both replanted B. pendula and surrounding P. sylvestris from the previous generation. Low productivity of B. pendula stands (45.0–76.1 m3·ha–1), high mortality rates, and comparatively low vigor of trees (measured as crown densities) indicated a strong impact of root rot. Based on somatic incompatibility tests, we detected large spreading areas of clones of H. annosum (up to 48 m across) and old (35- to 40-year-old) clonal individuals. Territorial clones covered areas that encompassed both previous stands of P. sylvestris and current stands of B. pendula. Our results showed that H. annosum is able to persist in root systems of diseased trees for decades and readily attack birch replanted on infested sites. In addition, a total of 83 fungal species (out of 398 isolates) was found as a result of sampling 508 B. pendula, 49 P. sylvestris, 21 Juniperus communis L., and 1 Salix cinerea L. trees.


2002 ◽  
pp. 49-58 ◽  
Author(s):  
Milosav Andjelic

Several adverse factors of abiotic and biotic nature affect the vitality and decline of spruce and fir in the region of NP "Durmitor" and NP "Biogradska Gora". The most significant adverse abiotic factor is air pollution. Among the adverse biotic factors, the most significant is by all means the parasitic fungus Heterobasidion annosum. The damage caused by this fungus is especially severe in spruce and fir stands in the region of the NP "Durmitor". The infection intensity is approximately the same in both species. The damage caused by H. annosum is greater in the forests of NP "Durmitor", than in the forests of NP "Biogradska Gora". This can be explained by the fact that spruce and fir stands on Durmitor were felled without maintaining the forest order. In the virgin forest reserve NP "Biogradska Gora" in the past there were no fellings, i.e. the impact of anthropogenic factors was excluded. Fungus H. annosum cannot be eliminated form spruce and fir stands on Durmitor, but the treatment of stumps (immediately after the sanitation felling) with "Penofil" or "Borax" can check the velocity of its spread. In this way, the forest is given an opportunity to form more resistant populations through a long period by natural selection .


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Maider Pagola Ugarte ◽  
Souzana Achilleos ◽  
Annalisa Quattrocchi ◽  
John Gabel ◽  
Ourania Kolokotroni ◽  
...  

Abstract Background Understanding the impact of the burden of COVID-19 is key to successfully navigating the COVID-19 pandemic. As part of a larger investigation on COVID-19 mortality impact, this study aims to estimate the Potential Years of Life Lost (PYLL) in 17 countries and territories across the world (Australia, Brazil, Cape Verde, Colombia, Cyprus, France, Georgia, Israel, Kazakhstan, Peru, Norway, England & Wales, Scotland, Slovenia, Sweden, Ukraine, and the United States [USA]). Methods Age- and sex-specific COVID-19 death numbers from primary national sources were collected by an international research consortium. The study period was established based on the availability of data from the inception of the pandemic to the end of August 2020. The PYLL for each country were computed using 80 years as the maximum life expectancy. Results As of August 2020, 442,677 (range: 18–185,083) deaths attributed to COVID-19 were recorded in 17 countries which translated to 4,210,654 (range: 112–1,554,225) PYLL. The average PYLL per death was 8.7 years, with substantial variation ranging from 2.7 years in Australia to 19.3 PYLL in Ukraine. North and South American countries as well as England & Wales, Scotland and Sweden experienced the highest PYLL per 100,000 population; whereas Australia, Slovenia and Georgia experienced the lowest. Overall, males experienced higher PYLL rate and higher PYLL per death than females. In most countries, most of the PYLL were observed for people aged over 60 or 65 years, irrespective of sex. Yet, Brazil, Cape Verde, Colombia, Israel, Peru, Scotland, Ukraine, and the USA concentrated most PYLL in younger age groups. Conclusions Our results highlight the role of PYLL as a tool to understand the impact of COVID-19 on demographic groups within and across countries, guiding preventive measures to protect these groups under the ongoing pandemic. Continuous monitoring of PYLL is therefore needed to better understand the burden of COVID-19 in terms of premature mortality.


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