scholarly journals The most frequent powdery mildews on forest woody species and their impact

2005 ◽  
pp. 9-29 ◽  
Author(s):  
Dragan Karadzic ◽  
Tanja Milijasevic

The most frequent fungus species known as powdery mildews, causing the diseases of forest trees, were studied. Among forest woody species, oaks are especially susceptible to powdery mildew attack, and among them pedunculate oak (Quercus robur L) is highly endangered. This paper reports 49 species of powdery mildews. However, Microsphaera alphitoides has the greatest significance in forest economy, causing the decline of seedlings in nurseries and also aggravating the natural regeneration of pedunculate oak. This fungus, together with gypsy moth and honey fungus (Armillaria mellea) participates in the dying of old oak trees. Powdery mildews can be successfully controlled by fungicides, and sulphur fungicides Karatan and Rubigan are especially effective.

1993 ◽  
Vol 58 ◽  
Author(s):  
D. Maddelein ◽  
J. Neirynck ◽  
G. Sioen

Mature  Scots pine (Pinus sylvestris  L.) stands are dominating large parts of the Flemish forest area. Broadleaved  species regenerate spontaneously under this pine canopy. This study studied  the growth and development of two planted pine stands with an older natural  regeneration, dominated by pedunculate oak (Quercus  robur L.), and discussed management options for  similar stands.     The results indicated a rather good growth of the stands, with current  annual increments of 5 m3.ha-1.yr-1. The pine overstorey is growing into valuable sawwood  dimensions, while the broadleaved understorey slowly grows into the  upperstorey. The quality of the regeneration is moderate but can be improved  by silvicultural measurements (pruning, early selection).     In both stands, an interesting (timber production, nature conservation)  admixture of secondary tree species is present in the regeneration. Stand  management is evolving from the classical clearcut system towards a  combination of a type of selection and group selection system.


2021 ◽  
Vol 13 (1(22)) ◽  
pp. 13-20
Author(s):  
Petru Cuza ◽  

Extreme weather events with high temperatures and strong sunlight have increased alarmingly in the last few decades, considerable affecting plant photosynthesis. In this study, the impact of thermal stress on photosystem II activity in the leaves of pedunculate oak trees (Quercus robur L.) of different ecological origin was assessed. Four days after the thermal shock application with a temperature of 50°C during 20, 40, 60 minutes, the processes of recovery on photosystem II activity in the leaves of the oak trees in the investigated provenances took place with different speed and fullness. The recovery of the functional state of photosystem II in the leaves of the trees showed that in the environmental conditions of the ,,Plaiul Fagului” reservation territory an advanced thermotolerance to the thermal stress action was specifi c for the origin from the north of the country (Edinet). The leaves of the trees of local and southern origin showed a low resistance to the thermal stress action. The advanced adaptation capacity, the high growth rate of the trees from the northern provenance suggest that the acorn harvested from the oaks of northern origin can be used for the works of extension of the afforestation areas in the central area of the Republic of Moldova.


2018 ◽  
Vol 79 (4) ◽  
pp. 309-315
Author(s):  
Władysław Barzdajn ◽  
Maciej Bruder

Abstract In this paper, we present the results and analyse of tree height measurements, phenological observations (bud flushing), oak powdery mildew symptoms and multiple shoots of pedunculate oaks Quercus robur L. at the age of 12 years. The examined oaks belonged to 29 open pollination families. Family as well as individual heritability scored very highly for their respective indices. The calculated indices were 0.83 for tree height, 0.98 for flushing of buds, 0.53 for oak powdery mildew symptoms and 0.58 for the multi-stem index. Family seed orchards established using a completely randomized design are not a reliable substitute for progeny testing, because of the commonly small number of collected families.


Author(s):  
С.Н. Кружилин ◽  
Т.Ю. Баранова ◽  
А.А. Багдасарян

Государственный природный заказник "Горненский", расположенный в центральной части Ростовской области, являясь особо охраняемой природной территорией областного значения, имеет уникальные объекты, представленные искусственно созданными лесными насаждениями дуба черешчатого (Quercus robur L.). В современном лесном хозяйстве черноземной зоны дуб черешчатый продолжает занимать лидирующие позиции по хозяйственному значению. Большое внимание при выращивании леса уделяется продуктивности. Насаждения, устойчивые насаждение к болезням, вредителям и неблагоприятным природным явлениям, всегда являются продуктивными и имеют большой показатель запаса древесины на единицу площади. Усыхание дубрав в последние годы становится актуальной проблемой. Основными факторами этих процессов являются повреждения вредителями и инфекционными заболеваниями. Повышению устойчивости деревьев дуба черешчатого в насаждениях способствуют своевременные рубки ухода. Авторы провели анализ посадок дуба черешчатого, сформированных с участием основной сопутствующей породы – клена остролистного. Исследовано 2 варианта лесных культур дуба в условиях сухой дубравы (Д1), определены лесоводственно-таксационные показатели в разные возрастные периоды. Отмечается, что при отсутствии в них плановых рубок ухода в периоды с 25 до 40 и с 35 до 50 лет происходит падение бонитета с 1 до 2 класса. Наряду с этим отмечается суховершинность деревьев, что приводит к задернению поверхности почвы и, соответственно изменению условий произрастания. The Gornensky State NatureReserve,situated in the central part of the Rostov Region, isa protected natural area of regional significance. The reserve contains unique objects, represented by artificially created forest stands of pedunculate oak (Quercus robur L.). In the modern forestry of the Chernozem zone,pedunculate oak continues to take a leading position in terms of its economic value. Much attention is paid to productivity when growing forests. Plantings that are resistant to diseases, pests, and adverse natural phenomena are always productive and have a large stock of wood per unit area. The diebackof oak forests has become an urgent problem in recent years. The main factors of these processes are damage by pests and infectious diseases. Timely improvement felling of oak trees helps to increase the stability of the stands. The authors analyzed plantings of petiolate oak formed with the participation of the main accompanying species– Norwaymaple. Twovariants of forest oak plantationsin the conditions of a dry oak forest (D1) were studied, and forestry and taxation indicators were determined for different age periods. It is noted that in the absence of planned improvement felling in the periods from 25 to 40 and from 35 to 50 years, there is a drop in the yield class from 1 to 2. Along with this, the diebackof trees is noted, which results inthe grassing-downof the soil surface and, accordingly, changes in the growing conditions.


2012 ◽  
Vol 73 (2) ◽  
pp. 137-141
Author(s):  
Tomasz Kałuża

Weryfikacja modelu stateczności drzew na terenach zalewowych na przykładzie dębu Quercus robur L., sosny Pinus sylvestris L. i olchy Alnus glutinosa (L.) Gaertn


2014 ◽  
Vol 66 (4) ◽  
pp. 1659-1672 ◽  
Author(s):  
Slobodan Milanovic ◽  
Ljubodrag Mihajlovic ◽  
Dragan Karadzic ◽  
Libor Jankovsky ◽  
Predrag Aleksic ◽  
...  

Gypsy moths and powdery mildew play a significant role in oak decline processes. However, information is lacking on the effects on the gypsy moth of impaired tree vitality caused by defoliation or parasite infection. We assessed how pedunculate oak leaves collected from vigorous, declining, and infected trees influenced gypsy moth preference and performance (growth and nutritional indices). We found a negative effect of powdery mildew-infected leaves on gypsy moth performance, while declining trees had positive effects on gypsy moth performance and preference. All examined parameters of larvae fed declining oak leaves were higher than those of larvae fed vigorous oak leaves. Increased growth on declining oak leaves was caused by both higher consumption and more efficient food utilization. The results of this research could help us to better understand multitrophic interactions in complex communities such as oak forests.


2020 ◽  
Vol 287 (1935) ◽  
pp. 20201303
Author(s):  
Laura J. A. van Dijk ◽  
Johan Ehrlén ◽  
Ayco J. M. Tack

Insects and pathogens frequently exploit the same host plant and can potentially impact each other's performance. However, studies on plant–pathogen–insect interactions have mainly focused on a fixed temporal setting or on a single interaction partner. In this study, we assessed the impact of time of attacker arrival on the outcome and symmetry of interactions between aphids ( Tuberculatus annulatus ), powdery mildew ( Erysiphe alphitoides ), and caterpillars ( Phalera bucephala ) feeding on pedunculate oak, Quercus robur , and explored how single versus multiple attackers affect oak performance. We used a multifactorial greenhouse experiment in which oak seedlings were infected with either zero, one, two, or three attackers, with the order of attacker arrival differing among treatments. The performances of all involved organisms were monitored throughout the experiment. Overall, attackers had a weak and inconsistent impact on plant performance. Interactions between attackers, when present, were asymmetric. For example, aphids performed worse, but powdery mildew performed better, when co-occurring. Order of arrival strongly affected the outcome of interactions, and early attackers modified the strength and direction of interactions between later-arriving attackers. Our study shows that interactions between plant attackers can be asymmetric, time-dependent, and species specific. This is likely to shape the ecology and evolution of plant–pathogen–insect interactions.


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1425
Author(s):  
Bernd Degen ◽  
Yulai Yanbaev ◽  
Malte Mader ◽  
Ruslan Ianbaev ◽  
Svetlana Bakhtina ◽  
...  

As for most other temperate broadleaved tree species, large-scale genetic inventories of pedunculate oak (Quercus robur L.) have focused on the plastidial genome, which showed the impact of post-glacial recolonization and manmade seed transfer. However, how have pollen mediated gene flow and introgression impacted the large-scale genetic structure? To answer these questions, we did a genetic inventory on 1970 pedunculate oak trees from 197 locations in 13 European countries. All samples were screened with a targeted sequencing approach on a set of 381 polymorphic loci (356 nuclear SNPs, 3 nuclear InDels, 17 chloroplast SNPs, and 5 mitochondrial SNPs). In a former analysis with additional 1763 putative Quercus petraea trees screened for the same gene markers we obtained estimates on the species admixture of all pedunculate oak trees. We identified 13 plastidial haplotypes, which showed a strong spatial pattern with a highly significant autocorrelation up to a range of 1250 km. Significant spatial genetic structure up to 1250 km was also observed at the nuclear loci. However, the differentiation at the nuclear gene markers was much lower compared to the organelle gene markers. The matrix of genetic distances among locations was partially correlated between nuclear and organelle genomes. Bayesian clustering analysis revealed the best fit to the data for a sub-division into two gene pools. One gene pool is dominating the west and the other is the most abundant in the east. The western gene pool was significantly influenced by introgression from Quercus petraea in the past. In Germany, we identified a contact zone of pedunculate oaks with different introgression intensity, likely resulting from different historical levels of introgression in glacial refugia or during postglacial recolonization. The main directions of postglacial recolonization were south to north and south to northwest in West and Central Europe, and for the eastern haplotypes also east to west in Central Europe. By contrast, the pollen mediated gene flow and introgression from Q. petraea modified the large-scale structure at the nuclear gene markers with significant west–east direction.


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