Untersuchungen zur Biologie,Morphologie und Verbreitung von Herpotrichia parasitica (Hartig) E. Rostrup (vormals Trichosphaeria parasitica Hartig)

Studies on the biology, morphology and spread of Herpotrichia parasitica (Hartig) E. Rostrup (formerly Trichosphaeria parasitica Hartig). Part II: Method of infection, hosts and pure culture. H. parasitica (Hartig) E. Rostrup (conidial stage Pyrenocbacta parasitica Preyer et van der Aa) overwinters by means of both types of fruit bodies on the needles of hosts but also by means of mycelium which grows along the under sides of shoots during the growing season, reaches the buds and penetrates under the outer bud scales. Spread of the fungus is thus independent of spores. As well as Abies alba, other silver firs are attacked. Contact infection with mycelium on Picea sitchensis was also observed. Studies with pycnospores showed that germination on needles of host species varied with humidity. In culture the fungus grew best on 2 % malt agar, pH 6 at 21°C.     

Untersuchungen zur Biologie,Morphologie und Verbreitung von Herpotrichia parasitica (Hartig) E. Rostrup (vormals Trichosphaeria parasitica Hartig)1

Studies on thc biology, morphology ancl clistribution of Herpotrichin parasitica (Hartig) E. Rostrup (Trichosphaeria parasitica Hartig) 1. Distribution and morphology. H. paratsitica (Hartig) E. Rostrup (Impcrfcct stage Pyrcnochaeta parasitica Freyer ct van der Aa) occurs in Southern Bavaria on European silver fur. Thc Fungus produces thick cushions of mycelium on the under sidcs of shoots and ovcr thc stomatal rows on needles, penctrates bark tissue as well as necdlcs and causes dcath of needles. Spores of both stagcs gcrminate vcry well in water under various conditions; pycnosρores germinated on silvcr fir needles undcr laboratory Conditions.     

Note sur l'aptitude lignivore du Lachnellula willkommii (Hartig) Dennis,agent du chancre du mélèze

Note on the wood destroying capacity of Lachnellula willkommii (Hartig) Dennis, the larch canker fungus. The wood destroying capacity of Lachnellula willkommii in larch was studied in vitro using a method based on loss of weight. Two species of larch and their hybrid were used. The behaviour of the fungus on sapwood and heartwood differed.     

Only two weeks are required forTricholoma matsutake to differentiate ectomycorrhizal Hartig net structures in roots ofPinus densiflora seedlings cultivated on artificial substrate

There has been conflicting debate over many years regarding the trophic status ofTricholoma matsutake (Ito et Imai) Sing., and further investigations are necessary to better understandT. matsutake physiology, particularly carbon nutrition, during ectomycorrhizal symbiosis. For this purpose, we developed a technique to rapidly synthesizein vitro ectomycorrhizas betweenPinus densiflora Sieb. et Zucc. andT. matsutake on artificial substrate (vermiculite: perlite: peat: beech sawdust; 5:5:1:1.), without added sugar in the nutrient solution. Only 1 week was required before the first rudimentary Hartig net ‘palmetti’ could be observed in roots. Well-developed Hartig net structures appeared in taproots after 2 weeks and in lateral roots after 3 weeks. Such rapid root infection may be attributed to the quality of the substrate and the inoculum used. This research was supported by a grant from the Bio-oriented Technology Research Advancement Institution (BRAIN).     

Simple diagnosis of ectomycorrhiza formation and demonstration of the architecture of the Hartig net by means of a clearing technique

Coniferous ectomycorrhiza was cleared in KOH and bleached in H₂ 0₂ . After the treatment, the structure of the Hartig net and inner mantle could be studied in detail in entire mycorrhizal short roots. The Hartig net and inner mantle were found to be formed by the same type of labyrinthic tissue, a result of morphogenetic processes during mycorrhiza formation. Even early phases of mycorrhizal infection could easily be detected, which makes the method very suitable for diagnosticating mycorrhiza formation accurately.     

Der schwarze Schneeschimmel der Koniferen [Herpotrichia juniperi (Duby) Petrak und Herpotrichia Coulteri (Peck) Bose)

Brown felt blight on conifers [Herpotrichia juniperi (Duby) Petrak and Herpotrichia Coulteri (Peck) Bose]. Herpotrichiα Coulteri (Peck) Bose was found on Pinus montαnα Miller ssp. prostrαtα Tubeuf in various alpine regions of Eastern Switzerland at altitudes over 1900 m. Herpotrchia juniperi (Duby) Petrak, has a much greater distribution, a wider host-range, and more vigour and is thus more economically important. Severe damage, particularly on spruce may be caused in afforestations of high mountain regions (eg. in avalanche control afforestation). The brown felt blight fungus can be controlled with Zineb or Maneb. The chemicals at a concentration of 5 % (overdose-spraying) must be sprayed before the first snow-fall. A reduction of concentration reduces the effectivity.     

落叶松锉叶蜂为害的松林光谱特征分析

通过对不同程度危害的落叶松反射光谱进行测定,研究了不同程度危害的落叶松在绿光区、红光区和近红外区反射光谱的变化特征,并对光谱反射曲线进行微分分析。结果表明,绿光区、红光区和近红外区的落叶松光谱反射率随危害程度的加重分别呈现下降、上升和下降的趋势;对反射率曲线进行微分分析,健康落叶松、轻度、中度和重度为害后的一阶导数光谱反射率最大值随着危害程度增加而下降,并且向短波方向移动(蓝移)。实测光谱数据提取的归一化植被指数(NDVI)与落叶松锉叶蜂危害程度呈显著负相关,对应用遥感技术早期监测落叶松锉叶蜂灾害具有重要指示意义。     

Mycobiota in needles of Abies alba with and without symptoms of Herpotrichia needle browning

The ascomycete Nematostoma parasiticum (syn.: Herpotrichia parasitica) is commonly perceived as the causal agent of the so‐called Herpotrichia needle browning in silver fir (Abies alba). However, its fruitbodies are rarely present on symptomatic needles, which are also colonized by many presumably saprotrophic fungi. We compared the internal colonization of healthy and symptomatic needles on two sites in Poland. In addition, the endophytic mycobiota in needles of various age was recorded on two other sites without disease symptoms. Fungi were isolated from 95.6% of the dead needles and from 62.9% of the living needles on symptomatic trees, whereas on healthy trees, only 45.0% of the needles were colonized internally. Colonization frequency increased with needle age. From a total of 2017 isolates, 116 fungal taxa were identified. Frequency of many species was influenced by needle type. Anthostomella formosa, Gloeosporidiella sp., Hypoxylon fragiforme, Xylaria hypoxylon and X. polymorpha were the most common fungi isolated from living needles. In symptomless living needles, fungi occurred significantly more often in the basal than in the apical parts. In dead needles, the most common fungi were Alternaria alternata, Paraconiothyrium sporulosum, Fusarium sp., Mollisia cinerea, Rhizoctonia sp., Rhizosphaera oudemansii, Thysanophora penicillioides, Xylaria hypoxylon and X. polymorpha. Rhizoctonia sp. was the most frequently isolated fungus in dead needles (23.4%) but occurred rarely also in living needles (0.3–1.1%). The supposed pathogen N. parasiticum was detected only sporadically (at most in 0.6% of the needles). Our findings demonstrate the need for understanding the role of Rhizoctonia sp. in Herpotrichia needle browning disease aetiology.     

Scleroderris lagerbergii Gr.: The pathogen and disease symptoms

This introductory paper reports on the pathogen's history in Europe and North America; the connection between the ascogenous stage, Sc1eroderris lagerbergii and the conidial form, Brunchorstia pinea; and the disease symptoms in nurseries as well as in plantations.     

木霉菌和毛壳菌对板栗疫病的抗生作用

哈茨木霉Trichoderma harzianumT88菌株、深绿木霉T.atrovorideT95菌株和螺旋毛壳Chaetomium spiraleND35菌株与板栗疫病菌Cryphonectria parasiticaLY菌株的平板对峙培养结果表明,木霉菌对营养和空间有强烈的竞争作用,表现在可使病原菌菌丝消解,对病菌菌丝的生长有明显的抑制作用;毛壳菌生长速度较慢,但可形成抑菌带,使病菌不扩展。室内水培枝条接种试验结果表明,接种拮抗菌的拮抗效果好,而且先接种拮抗菌后接种病原菌的处理比拮抗菌和病原菌同时接种的处理效果还好,毛壳菌没有木霉菌的作用明显。接种枝条的木霉菌、毛壳菌和病原菌的再分离结果表明,T95和ND35的定殖能力强。     

宁化县横坑切梢小蠹虫害大发生与气候因子分析

以福建省宁化县为例,调查研究了横坑切梢小蠹的生物学特性、危害规律,分析了其与气候因子的关系,并探讨了对横坑切梢小蠹的防治方法。     

Growth and physiological responses of chestnut calli to crude extracts of virulent and hypovirulent strains of Cryphonectria parasitica

The effect of crude extracts (CEs) of virulent (V‐E4) and hypovirulent (H‐E13) Cryphonectria parasitica strains on growth and physiological activities of chestnut calli was investigated on cell cultures obtained from either a susceptible Castanea sativa or a resistant Castanea mollissima chestnut species. The V‐E4 CEs significantly reduced calli fresh weight in both species when used at 50 and 500 μg g^–1 and, in general, showed an inhibitory effect on either O₂ uptake and H⁺‐ATPase activity. Only the highest (500 μg g^–1) concentration of H‐E13 CEs had a detrimental effect on callus growth, whereas the lowest one (5 μg g^–1) induced a slight, but significant early increase in callus fresh weight of both genotypes. The O₂ uptake and H⁺‐ATPase activity were enhanced by the presence of H‐E13 CEs. The decrease of callus growth and physiological activities, caused by V‐E4 CEs, was attributed to toxic compounds produced by the C. parasitica virulent strain, whereas the stimulatory effects of H‐E13 CEs on the overall callus metabolism seemed to be due either to the lack or very reduced amount of phytotoxic compounds and to growth‐regulating substances produced only by the hypovirulent strain of the fungus.     

Le Linospora ceuthocarpa (Fr.) Munk ex Morelet,parasite foliaire des peupliers

Linospora ceuthocarpa (Fr.) Munk ex Morelet, a parasite of poplar leaves. Linospora ceuthocarpa (Fr.) Munk ex Morelet and its conidial stage Titaeosporina tremulae (Lib.) v. Luyk are experimentally connected and described. The life history of the disease on poplar leaves is studied.     

Susceptibility of cones and seeds to fungal infection in a pine (Pinus spp.) collection

Summary Thirty‐one fungi, members of Ascomycota and Deuteromycota, were isolated from cones/seeds of 28 hosts (Pinus spp.) originating from East Asia, Europe and North America, and growing at the Montreal Botanical Garden, Canada. A total of 21 taxa of these isolated fungi are considered pathogens. The damage severity was most prevalent on Diploxylon pines of European provenance (Pinus nigra, Pinus mugo and Pinus sylvestris), and one indigenous North American species (Pinus albicaulis). Twelve fungi occurred on different hosts, i.e. Sphaeropsis sapinea (12), Herpotrichia juniperi (8), Truncatella hartigii (7), Ceuthospora sp. (5), Fusarium, spp. (5), Pestalotiopsis funerea (3), Phomopsis sp. (3), Valsa spp. (anamorph. Cytospora) (3), Diaporthe sp. (3), Fusicoccum sp. (2) and Sirococcus strobilinus (2). Sphaeropsis sapinea, Herpotrichia juniperi, Phomopsis conorum, Truncatella hartigii, Tubercularia sp. and Valsa spp. were related to high cone and seed damage. For the most frequently observed Sphaeropsis sapinea damage, the subgenus Haploxylon was less susceptible than Diploxylon, and P. sylvestris less than P. nigra and P. mugo. Pinus resinosa showed more tolerance to S. sapinea. Truncatella hartigii was more frequently associated with necrotic lesions on cones/seeds in comparison with Pestalotiopsis funerea. The results are discussed in the context of arboretum, seed orchard, nursery and quarantine management.     

Long‐term field study of transgenic hypovirulent strains of Cryphonectria parasitica in a forest setting

Transgenic hypovirulent strains of Cryphonectria parasitica, the chestnut blight fungus, engineered to contain a chromosomally integrated full‐length infectious cDNA copy of virulence‐attenuating hypoviruses, differ from natural hypovirulent strains in the ability to transmit hypoviruses to ascospore progeny and with 100% efficiency through asexual spores. We report the results of a long‐term field study that examined whether these properties result in enhanced hypovirulence establishment, dissemination and persistence under field conditions. Informed by previous field results using a severe hypovirus, this study that employed 144 American chestnut trees was designed to provide improved inoculum formulation and delivery and to include the use of a mild hypovirus isolate (less debilitating) CHV‐1/Euro7 in an attempt to increase dissemination. Isogenic transgenic hypovirulent (TG), non‐transgenic cytoplasmic hypovirulent (CH) or virus‐free virulent (V) treatment strains were applied to artificially initiated and natural C. parasitica cankers three times each year for 7 years. Reservoirs of treatment inoculum also were initiated and refreshed annually for the first 6 years of the study. Sampling of 111,000 individual ascospores from 4,500 perithecia confirmed hypovirus‐containing spermatia successfully transmitted TG hypoviruses to ascospore progeny under field conditions. Surprisingly, TG ascospore progeny were recovered 3 years after the last annual application of treatment inoculum. Repeated sampling of over 440 cankers revealed dissemination of both CH and TG hypovirulent strains. However, no significance differences in establishment or dissemination were observed for the two hypovirulent strains. The results are discussed in terms of the contribution of ascospore progeny to infection, competition by endemic virulent C. parasitica, size of inoculated trees and the biological control potential of TG hypovirulent strains.     

板栗疫病发生原因调查及对策

通过对板栗疫病发生现状调查，认为板栗疫病发生与管理粗放、栽植不合理、蛀干害虫危害、人为造成大量伤口等有一定关系，提出今后应加强检疫、抚育、伤口保护、重病区改造、药剂防治等工作 。     

Eutypella parasitica naturalised in Bohemian and Polish Silesia

In 2015 and 2016, the North American maple tree pathogen Eutypella parasitica was identified in Bohemian and Polish Silesia. To date, the pathogen has been recorded in 35 locations over an area of approximately 400 km². It has been found primarily in natural stands in Silesia in several types of ravine and alluvial forests, in other natural or commercial forests, in riparian stands and in open landscapes. The proportion of diseased maples ranged between approximately 1% and 50% in certain locations. Acer pseudoplatanus was confirmed as the main host but infections were also detected on A. platanoides and A. campestre. E. parasitica damages the most valuable sycamore timber and represents a clear risk for maple cultivation in the region.     

Growth and ultrastructural modifications to chestnut calli induced by culture filtrates of virulent and hypovirulent Cryphonectria parasitica strains

Callus cultures of two susceptible Castanea sativa cultivars, ‘Garrone rosso’ and ‘Clone 71’ were grown on culture medium supplemented to 50% with culture filtrates (CFs) from E4 virulent (E4-V) or E13 hypovirulent (E13-H) Cryphonectria parasitica strain, respectively. E13-H CFs caused a reduction in fresh weight and an increase in dry weight on calli of both genotypes. E4-V CFs did not induce any modification of these parameters compared with the control, but fresh weight of ‘Clone 71’ was reduced. Light and electron microscopy observation showed the presence of large osmiophilic aggregates in the vacuoles and, sometimes, the ruptured tonoplast in the E4-V treated calli. Calli grown on El 3-H CFs had a meristematic-like appearance, with small, scarcely vacuolated cells containing altered mitochondria and plasmalemma proliferations.     

Morphological and cultural variation of Seiridium spp. from cankered Cupressaceae hosts in New Zealand

Studies of Seiridium. spp. isolated from cankered cypresses and related hosts in New Zealand indicate that only 2 species are present, namely, 5. unicorne and 5. cardinale, following sdtton, and not 3 species as proposed by boesewinkel. Apart from a difference in the presence/absence of conidial appendages, the two pathogens are similar in many biological characteristics. Isolates of S. unicorne showed a continuum of variation in conidial size and cultural morphology making it difficult to justify splitting of the species.     

The response of ectomycorrhizal fungi on Pinus densiflora seedling roots to liquid culture

Japanese red pine (Pinus densiflora) seedlings taken from a nursery were grown in liquid culture with all roots entirely submerged in water. The aims of the present study were to observe the reactions of preformed ectomycorrhizae to liquid culture and to examine new infections by ectomycorrhizal fungi on newly formed root tips in liquid culture. Inoculation levels were controlled by trimming the ectomycorrhizal roots to one of three selected root lengths. The results showed that the mantles of pre-formed ectomycorrhizae were lost during the 8 weeks of the liquid culture and that these preformed root tips became blackish and wrinkled, but Hartig nets remained in these blackish root tips. On the newly formed lateral root tips, no ectomycorrhizal mantles were formed, although Hartig nets were found. In addition, the level of inoculum did not affect the frequency of Hartig nets in newly formed root tips, suggesting that the density of inoculum was more important than the amount of inoculum for new infection. In conclusion, ectomycorrhizal fungi endured and infected new roots while submerged; however, only Hartig nets were formed and not mantles.