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Funding for Open Access provided by the UMD Libraries Open Access Publishing Fund., Species of Cosmospora are parasites of other fungi (mycoparasites), including species belonging to the Xylariales. Based on prior taxonomic work, these fungi were determined to be highly host specific. We suspected that the association of Cosmospora and their hosts could not be a result of random chance, and tested the cospeciation of Cosmospora and the their hosts with contemporary methods (e.g., ParaFit, PACo, and Jane). The cophylogeny of Cosmospora and their hosts was found to be congruent, but only host-parasite links in more recent evolutionary lineages of the host were determined as coevolutionary. Reconciliation reconstructions determined at least five host-switch events early in the evolution of Cosmospora. Additionally, the rates of evolution between Cosmospora and their hosts were unequal. This pattern is more likely to be explained by pseudocospeciation (i.e., host switches followed by cospeciation), which also produces congruent cophylogenies.

A series of small-scale controlled inoculation experiments has been conducted during 2005–2009 to determine whether temperature and controlled atmosphere (CA) storage conditions affect significantly the incidence of Botrytis cinerea and Neonectria galligena rots of apples and to assess whether CA regimes can be ‘fine-tuned’ to suppress fungal rotting. The incidence of B. cinerea and N. galligena rots on apple was reduced consistently by storage in lower temperatures (1.5–2°C). In no case was the disease incidence significantly higher than that under air storage conditions. However, the effect of CA conditions on rot development varied greatly from year to year so that overall there were no significant effects of CA conditions on the incidence of rot during storage till the following April. Thus, we can neither fine-tune CA conditions to reduce rot development nor exploit the advantages of lower storage temperatures for Cox and Bramley for this purpose due to inevitable development of low temperature breakdown. Further research is needed to study the effects of ethylene control technologies and modulated storage temperatures on rot development.

Neonectria galligena can cause European canker of apple as well as fruit rot. Healthy unwounded fruits on potted trees of cvs Cox, Bramley and Gala were inoculated with conidia of N. galligena to investigate the effects of wetness duration and fruit maturity on rot development. Overall, the incidence of fruit rot was influenced more by fruit maturity at the time of inoculation than by duration of wetness (6–48 h). Young fruit were most susceptible to infection, with 50% of fruit infected when inoculated up to 4 weeks after full bloom. The susceptibility decreased initially until c. 2 months after full bloom and then increased gradually until harvest. Almost all preharvest symptoms (eye rot) developed only on the fruit inoculated up to 4 weeks after full bloom. All other rots were observed after six-month postharvest storage under controlled atmospheric conditions. However, the relative proportion of preharvest eye rots and postharvest storage rots varied greatly among three years. The effect of wetness duration was only significant for fruit inoculated in their early stages of development but not for those inoculated near harvest. Regression models were developed to describe the observed effects of fruit maturity and wetness on the incidence of total nectria rots.

Zusammenfassung Die Laubholz-Lachniden unterhalten sehr enge Trophobiosebeziehungen zu Ameisen. Ohne die Ameisen konnen sie auf die Dauer nicht existieren. Die Rote Waldameise Formica rufa ist in der Lage, in der Nahe ihrer Nester fast alle Rauber wirksam von den Lausen abzuwehren. Die wirksamsten Feinde sind Vogel, die wahrend des Winters regelmasig den grosten Teil der Schizodryobius-Gelege verzehren. L. roboris konnten in Deutschland noch keine Schaden nachgewiesen werden, wahrend er in Ungarn als Erreger des Eichenkropfes aufgetreten sein soll. S. pallipes und S. longirostris bewirken durch ihre Saugtatigkeit eine Entartung des Kambiums ihrer Nahrpflanzen. An Buche fuhrt das zu Risbildungen und im Zusammenwirken mit dem Buchenkrebspilz Nectria ditissima zum Absterben von Zweigen und jungeren Pflanzen. An Eiche entstehen Rindenverfarbungen, Ris- und Kropfbildungen und eine Reihe weiterer Schaden, die ebenfalls das Absterben von Zweigen oder Jungpflanzen nach sich ziehen konnen. Summary The Lachnids of deciduous trees maintain very close trophibiotic relationships with ants and cannot exist for long without these insects. Near their nests, red wood ants, Formica rufa, can effectively protect the aphids from almost all predators. The most effective enemies are birds which regularly consume the greater part of the Schizodryobius egg masses in the winter. Up to now, it has not been possible to prove any damage by L. roboris in Germany, whereas this appears to be the cause of oack canker (Eichenkropf) in Hungary. By their feeding activities, S. pallipes and S. longirostris cause a degeneration of the cambium of their host trees. On beech, this leads to crack formation and, in conjunction with the beech canker fungus, Nectria ditissima, to the death of twigs and young trees. On oak, bark discoloration, crack and canker (Kropf) formation and a number of further symptoms occur, which can also cause the death of twigs and young trees.

Stands of eastern hemlock [(Tsuga canadensis (L.) Carriere] in the north-eastern United States are in decline, in part from the attack of elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae). From 2001 to the present, a natural epizootic has been observed in populations of F. externa. Initially discovered at the Mianus River Gorge Preserve in Bedford, New York, the epizootic has also been detected in Pennsylvania, New Jersey and Connecticut. Understanding and assessing the identity of the pathogenic micro-organisms responsible for this natural mortality is crucial for developing biological controls for this pest. We have isolated and taxonomically and genetically identified entomopathogens, phytopathogens and endophytic fungi associated with F. externa. Isolates of the following were obtained: Colletotrichum sp., Lecanicillium lecanii, Beauveria bassiana, Metarhiziopsis microspora, Myriangium sp., Mycosphaerella sp. anamorph, Nectria sp., Botrytis sp., Phialophora sp. and Fusarium sp.

Fungi and bacteria on the external surfaces of four gorse-associated insect species: gorse seed weevil Apion ulicis Forster (Coleoptera: Apionidae), light brown apple moth Epiphyas postvittana Walker (Lepidoptera: Tortricidae), gorse pod moth Cydia ulicetana Denis and Schiffermuller (Lepidoptera: Tortricidae) and gorse thrips Sericothrips staphylinus Haliday (Thysanoptera: Thripidae), were recov- ered by washing and plating techniques. The isolates were identified by morphology and polymerase chain reaction (PCR) restriction fragment length polymorphism and sequencing of internally tran- scribed spacer (ITS) and 16S rDNA. A culture-independent technique (direct PCR) was also used to assess fungal diversity by direct amplification of ITS sequences from the washings of the insects. All insect species carried Alternaria, Cladosporium, Corallomycetella, Penicillium, Phoma, Pseudozyma spp. and entomopathogens. Ninety-four per cent of the 178 cloned amplicons had ITS sequence similarity to Nectria mauritiicola (syn. Corallomycetella repens) .E. postvittana carried the largest fungal spores (spore mean surface area of 126 mm 2 ) and the most fungal colony forming units per insect. Methylo- bacterium aquaticum and Pseudomonas lutea were isolated from all four insect species. P. fluorescens was the most abundant bacterium on the lepidopteran insects. This study presents the diversity of microbial taxa on insect exoskeletons, and provides the basis for developing a novel mycoherbicide delivery strategy for biological control of gorse using insects as vectors of a plant pathogen.

BACKGROUND: The novel natural product cinnacidin was isolated from a fungal fermentation extract of Nectria sp. DA060097. The compound was found to contain a cyclopentalenone ring system with an isoleucine subunit linked through an amide bond. Initial biological characterization of cinnacidin suggested promising herbicidal activity. RESULTS: Two synthetic analogs, (2S,3S)-2-[(3RS,3aSR,6aRS)-3-methoxy-4-oxo-3,3a,4,5,6,6a-hexahydropentalen-1-ylcarbamoyl]-3-methylvaleric acid and benzyl (2S,3S)-2-[(3RS,3aSR,6aRS)-3-methoxy-4-oxo-3,3a,4, 5,6,6a-hexahydropentalen-1-ylcarbamoyl]-3-methylvalerate, were prepared for further characterization, and their herbicidal activities were compared with that of cinnacidin. CONCLUSIONS: The synthetic compounds were highly phytotoxic on a range of weeds. Based on the symptoms in treated plants, the mode of action of these compounds is suggested to be similar to that of coronatine and jasmonic acid. Coronatine was more active against warm-season grasses, while the cinnacidin benzyl ester analog was more effective on cool-season grasses. In a seedling growth bioassay conducted on bentgrass, the cinnacidin analog was equivalent in activity to coronatine. Copyright © 2008 Society of Chemical Industry

Summary Fungi isolated from the oak (Quercus robur) rhizosphere were tested for their effects on rhizomorph formation and growth of 16 isolates of Armillaria ostoyae sampled in three localities in western Poland. The number of rhizomorphs, number of rhizomorph apices, and rhizomorph length and weight increased most in the presence of Penicillium lanosum, Penicillium notatum, Cylindrocarpon destructans, Penicillium spinulosum and Mycelium radicis atrovirens α and, to a lesser extent, in the presence of Nectria grammicospora. Inhibition of rhizomorph formation was caused by Trichoderma hamatum and Trichoderma viride in two A. ostoyae isolates and by M. radicis atrovirens α and P. spinulosum in one A. ostoyae isolate. It is suggested that variation in sensitivity to microbial stimulation within A. ostoyae is associated with the environmental and nutritional conditions of its original habitat. Isolates from nutrition-rich localities, with 20% of the land area covered by deciduous trees, were particularly susceptible to stimulation by rhizosphere fungi. Resume Les champignons isoles de la rhizosphere de chene (Quercus robur) ont ete testes pour leurs effets sur la formation et la croissance des rhizomorphes de 16 isolats d’Armillaria ostoyae provenant de 3 localites de Pologne occidentale. L'augmentation du nombre de rhizomorphes et d'apex de rhizomorphes, de la longueur et du poids des rhizomorphes a ete la plus importante en presence de Penicillium lanosum, Penicillium notatum, Cylindrocarpon destructans, Penicillium spinulosum et Mycelium radicis atrovirensα et, a un moindre degre, en presence de Nectria grammicospora. Trichoderma hamatum et Trichoderma viride ont inhibe la formation de rhizomorphes chez deux isolats d’A. ostoyae et M. radicis atrovirensα et P. spinulosum chez un isolat. Nos resultats suggerent que la variation de sensibilitea la stimulation microbienne entre isolats d’A. ostoyae est associee aux conditions environnementales et nutritionnelles de leurs habitats d'origine. Les isolats provenant de localites riches sur le plan nutritif, avec 20% de la surface couverte par des essences feuillues, sont particulierement sensibles a la stimulation par des champignons de la rhizosphere. Zusammenfassung Verschiedene Rhizospharenpilze von Quercus robur wurden auf ihre Wirkung auf die Bildung und das Wachstum der Rhizomorphen von 16 A. ostoyae-Isolaten getestet, die aus drei Gebieten in Westpolen stammten. Penicillium lanosum, P. notatum, Cylindrocarpon destructans, Penicillium spinulosum und Mycelium radicis atrovirens α erhohten sowohl die Anzahl der Rhizomorphen und der Rhizomorphenspitzen als auch die Lange und das Gewicht der Rhizomorphen am deutlichsten. Nectria grammicospora war weniger wirksam. Trichoderma hamatum und T. viride hemmten die Rhizomorphenbildung bei zwei Isolaten von A. ostoyae, M. radicis atrovirens α und P. spinulosum hatten diesen Effekt bei einem Isolat. Aus den Daten ergibt sich, dass die unterschiedliche Empfindlichkeit der verschiedenen Isolate von A. ostoyae auf die mikrobielle Stimulation mit den Umweltbedingungen am Herkunftsort zusammenhangen konnte. Isolate von nahrstoffreichen Standorten, wo 20% der Flache mit Laubgeholzen bestockt waren, reagierten besonders deutlich auf die Prasenz von Rhizospharenpilzen.

Eight fungal assemblages were isolated from thin branch roots (0.5–1 mm diameter) of living oak trees (Quercus robur) and their stumps 2 years after felling. The roots were serially washed or surface-sterilized with ethanol and hypochlorite. The thin roots were inhabited by fungi that are stimulants of Armillaria rhizomorphs as found previously in thick roots (0.5–1 cm diameter). However, unlike thick roots, the densities of the fungi in serially washed roots were significantly less in stump roots than in living roots. Among the most common ‘stimulants’, the frequencies of Cylindrocarpon didymum, Mortierella gracilis, Mor. microspora var. macrocystis, Mycelium radicis atrovirens, Nectria grammicospora, Pseudogymnoascus roseus and Sporothrix schenckii were usually significantly greater in stump roots than in living roots, while the frequencies of Chrysosporium merdarium, Cy. destructans, Mor. hygrophila, Penicillium adametzii, Pe. citrinum, Pe. daleae, Pe. janczewskii and Pe. spinulosum were usually significantly less in stump roots. The frequency of Trichoderma viride was less in the stump roots. Serial washing of roots was more effective than chemical surface-sterilization in the detection of Armillaria rhizomorph ‘stimulants’. The significance of these findings in the ecology and risk assessment of Armillaria in plantations is discussed.

Summary In field tests conducted on freshly cut red pine (Pinus resinosa) logs, the antagonistic fungus Phaeotheca dimorphospora formulated as pre-colonized rye grains reduced colonization of wood tissue by Heterobasidion annosum to less than 2% over the 2 months following inoculation. However, compared to controls, a water suspension of P. dimorphospora did not reduce the infection, but rather promoted colonization by H. annosum after a 2-month exposure. Production of antifungal metabolites by P. dimorphospora in the rye grains and better colonization of the logs by the antagonist were observed with the rye grain formulation. In this field test, the most effective treatment to control H. annosum was the application of an oidial suspension of Phlebiopsis gigantea. This fungus completely inhibited colonization by H. annosum mostly by rapid colonization of wood tissue. All treatments with P. gigantea, P. dimorphospora and rye grains influenced the naturally occurring mycoflora. The most important species composing this mycoflora were Hormonema sp., Mortierella spp., Mucor hiemalis f. hiemalis, Nectria sp., Pesotum sp., P. gigantea, Tympanis spp., Trichoderma spp. and an unknown basidiomycete. Resume Des essais realises sur le terrain sur des buches de pin rouge partiellement enterrees ont indique que l'application de Phaeotheca dimorphospora sous forme de grains de seigle pre-colonises a reduit l'infection des tissus par Heterobasidion annosum. Ce dernier a ete isole dans moins de 2% des echantillons au cours des deux mois d'observation. Toutefois, le traitement des buches avec une suspension liquide de P. dimorphospora n'a demontre aucune efficacite, elle a meme favorise la colonisation des tissus par H. annosum apres les deux mois d'exposition. La production de metabolites antifongiques dans les grains ainsi qu'une meilleure colonisation des tissus ont ete observees avec la formulation grains de seigle. Dans cette experience, le meilleur traitement pour inhiber l'infection par H. annosum a ete l'application de Phlebiopsis gigantea. Ce dernier a completement inhibe la colonisation par l'agent pathogene principalement en occupant abondamment et rapidement les tissus du bois. Cet essai a egalement permis d'observer que tous les traitements ont influence la nature et la composition de la colonisation naturelle par les champignons. Les principales especes retrouvees ont eteHormonema sp., Mortierella spp., Mucor hiemalis f. hiemalis, Nectria sp., Pesotum sp., P. gigantea, Tympanis spp., Trichoderma spp. et un basidiomycete inconnu. Zusammenfassung In frisch geschnittenen Stammabschnitten von Pinus resinosa wurde in Freilandversuchen die antagonistische Wirkung von Phaeotheca dimorphospora untersucht. Bei einer Applikation in Form von besiedelten Roggenkornern wurde das Holz zwei Monate nach der Inokulation zu weniger als 2 % von Heterobasidion annosum besiedelt. Wurden die Stammabschnitte jedoch mit einer wassrigen Suspension von P. dimorphospora behandelt, zeigte sich keine Hemmwirkung, sondern die Besiedelung durch H. annosum nach zwei Monaten war sogar erhoht. Die Inokulation mit Roggenkornern forderte die Bildung von pilzhemmenden Metaboliten durch P. dimorphospora ebenso wie seine Besiedelung des Holzes. In diesem Freilandversuch war die Behandlung mit Phlebiopsis gigantea am wirksamsten. Der Pilz verhinderte die Besiedelung durch H. annosum durch seine rasche Kolonisierung des Substrates vollkommen. Alle Behandlungen (Phlebiopsis gigantea, Phaeotheca dimorphospora und Roggenkorner) beeinflussten die Art und Zusammensetzung der Besiedelung durch naturlich vorkommende Pilze. Die wichtigsten nachgewiesenen Arten waren Hormonema sp., Mortierella spp., Mucor hiemalis f. hiemalis, Nectria sp., Pesotum sp., P. gigantea, Tympanis spp., Trichoderma spp. und ein nicht identifizierter Basidiomyzet.

Beech canker caused by Nectria ditissima was abundant in many plots of a large beech provenance trial in Germany. In 149 plots a total of 9015 plants were assessed. No difference in susceptibility of individual provenances was established. However, significant spatial correlation was found between canker incidence in the plantation and the distance to neighbouring diseased shelterwood. The latter evidently served as a source of inoculum. Predominant juveniles tended to be more infected presumably by being more exposed to the inoculum. Trees planted up to 20 m from diseased shelterwood were most significantly infected, up to 48% per plot. In order to ascertain the role of wind for dispersing inoculum, distance zones were combined with locally predominant wind directions. The resulting wind dispersal zones served better for modelling disease dispersal than the distance zones. Repartition spatiale du chancre du hetre a Nectria ditissima dans un essai international de provenances Le chancre aNectria ditissimaetait abondant dans un grand essai de provenances de hetre en Allemagne. Dans 149 placeaux, 9015 arbres ont ete examines. Aucune difference de sensibilite n'a ete observee entre les provenances. Cependant, une correlation spatiale significative a ete trouvee entre l'abondance des chancres et la distance aux arbres malades du couvert. Ceux-ci constituaient a l'evidence la source d'inoculum. Les jeunes arbres les plus grands tendaient aetre les plus infectes, etant probablement plus exposes a l'inoculum. Les arbres plantes jusqu'a 20 metres des arbres malades du couvert etaient significativement les plus infectes, jusqu'a 48% par placeau. Dans le but d'evaluer le role du vent dans la dispersion de l'inoculum, la direction des vents dominants a ete prise en consideration. Les zones definies en fonction de la direction du vent etaient un meilleur indicateur que les distances pour modeliser la repartition de la maladie. Raumliche Ausbreitung von Buchenkrebs in einem Provenienzversuch In einem Buchenprovenienzversuch in Deutschland trat ein relativ hoher Befallsgrad mit Buchenkrebs (Nectria ditissima) auf. In 149 Parzellen wurden insgesamt 9015 Baume ausgewertet. Mittels Varianzanalyse konnte keine Abhangigkeit des Befallsgrads von der Provenienz nachgewiesen werden. Dagegen ergab sich ein hochsignifikanter Zusammenhang mit dem Abstand der Parzellen auf der Lee-Seite von infizierten Altbuchen in der Nachbarschaft. Diese waren offensichtlich die Infektionsquelle. In der Verjungung vorherrschende Baume waren uberdurchschnittlich infiziert, da sie den Pilzsporen mehr ausgesetzt sind. Ferner waren Parzellen im Umkreis von 20 Metern um infizierte Uberschirmung signifikant am starksten infiziert, bis zu 48% pro Parzelle. Mit Hilfe der Abstandszonen und den vorherrschenden Windrichtungen wurden Windverbreitungszonen entwickelt. Damit lasst sich die Ausbreitung der Krankheit besser modellieren als mit Hilfe von Abstandszonen.

The structure and development of perithecia in five collections of Epichloefrom Europe and North America were studied. Perithecia in early stages of development are oblong to ovate in overall shape. Dichotomously branched paraphyses form on the bottom and sides of the inner walls of the perithecial primordium. As the ovate primordium expands, a mound of ascogenous mycelium develops in its base. As asci develop from the ascogenous mound, paraphyses proximal to asci evanesce and no paraphyses are observable within the cluster of asci. In E. amarillans and E. baconii paraphyses are converted into pseudoparenchyma-like tissues, while in E. typhina paraphyses remain filamentous until they evanesce. Ascospore development is seen to differ among all three species of Epichloe ¨.The development and structure of the Epichloe ¨ centrum are compared to those of the Nectria and Xylaria types. It is apparent that a distinct type of centrum is present in Epichloe ¨,and perhaps all of the Clavicipitaceae. It is proposed that the Epichloetype centrum may represent a key feature for distinguishing the Clavicipitaceae from the Hypocreaceae or other groups of pyrenomycetes.

Field surveys and inoculation experiments were carried out in order to determine the most important stem-canker fungi on willows planted for energy production. The pathogenicity of different fungal isolates and factors influencing infection were studied in the field and in greenhouse experiments, where canker extension was measured after inoculation either on dormant plants or on plants undergoing active growth.

The diversity of Ascocoryne cylichnium, Nectria fuckeliana and Neobulgaria premnophila isolates expressed as variation in their fatty acid and sterol composition was investigated. Despite high within-species variation, distinct differences in the fatty acid and sterol composition between species were evident.

Different combinations of two decay fungi (Heterobasidion annosum, Stereum sanguinolentum), two non-decay fungi (Nectria fuckeliana, Ascocoryne cylichnium), a yeast-like fungus and two bacteria (Bacillus pumilus, Enterobacter agglomerans) all of spruce origin, were inoculated into stems of 16 healthy-looking Picea abies. Growth and survival of the microbes were followed over the subsequent five years. The rapid upward vertical spread of the decay fungi during the first two years was followed by a later regression and loss of these decay fungi by the fifth year. The stems were effectively colonized by the bacteria, A. cylichnium and/or Neobulgaria premnophila which then persisted over the whole experimental period. The endophytic fungi, N. premnophila and A. cylichnium, were abundant in the stems of the experimental trees before inoculation.

To protect apple orchards from diseases efficiently, growers need farm-based rather than regional disease warning systems. This paper describes three PC-based systems from Horticulture Research International (GB). These systems, VENTEM, PODEM and NECTEM, provide warnings in the form of infection alerts and disease forecasts of Venturia inaequalis (scab), Podosphaera leucotricha (powdery mildew) and Nectria galligenu (European canker and fruit rot), respectively. The modular structure, operation and practical implementation of these systems are described and compared. A major input is weather data recorded automatically by Metos weather stations sited on farms. Each system has a weather-driven dynamic model simulating inoculum production and the infection process. The systems use information on quantity of inoculum, cultivar susceptibility and other host factors to produce disease forecasts which are specific to individual orchard blocks and cultivars.

A new antifungal diketopiperazine named haematocin was isolated from the culture broth of Nectria haematococca Berk. et Br. (880701a-1) causing blight disease on ornamental plants, Phalaenopsis spp. and Doritanopsis spp. Its structure was established by spectroscopic methods. Haematocin inhibited the germ-tube elongation and spore-germination of Pyricularia oryzae at the ED50 values of 30 microg/ml and 160 microg/ml, respectively.

Ilicicolins D, E, F, dechloroilicicolin D, ascofuranone and arthrichitin were isolated from the fermentation broth of Nectria sp (HIL Y 90 3333). The ilicicolins showed good fungicidal activity in planta.

Investigations into the dependence of beech bark necrosis on infection with Cryptococcus fagisuga in commercial beech-(Fagus sylvatica)forests. Occurrence and sequence of attack of Fagus sylvatica by Cryptococcus fagisuga, slime flux, and necrosis were followed with four different methods of observation. Under average climatic conditions provocation and development of individual successive infection waves overlap to such a high degree that, because of the relatively short duration of the scale attack and because of the long duration and the great variation of the intensity of the necrotic reaction of the susceptible members of the beech population, individual waves of attack can hardly be discriminated in time and space.

Variability of Fagus sylvatica susceptibility to Nectria coccinca, one of the agents of beech bark disease. N. coccinea was inoculated into wounds of young beeches raised from seeds of 6 bark diseased trees and 6 healthy ones in the same stand of the forest of Lyons. Classifieation of the progenies, according to the size of the necrosis, is in good agreement with the health of the mother trees. N. coccinca susceptibility of beech has a genetic origin.

Wound inoculation with an isolate of Nectria coccinea produced cankers in beech bark, the size of which was related to the severity of C. fagisuga infestation. Lesions were absent in most cases following surface inoculation of bark (non wounding) with very localised but heavy infestation. Inhibition of the host's response to fungal invasion is considered to be an important part of the insect's role in producing beech bark disease.

Concentrations of amino acids, total amino nitrogen, and phenols, ratio of phenol to amino nitrogen, and pH in the bark of American beech, Fagus grandifolia, were determined to see if these chemical constituents were correlated with susceptibility of trees to infestation by the beech scale, Cryptococcus fagisuga. The relationship of these bark constituents with scale infestation levels (none, light, and moderate), tree size (large vs. small trees), and bark shading was determined. Levels of some individual amino acids and total amino acid content in moderately infested trees were significantly higher than in uninfested trees. Large uninfested beech trees, which tend to be more readily infested by scale, had significantly higher concentrations of aspartic acid. Concentrations of phenol in the outer bark of both infested and uninfested trees were significantly higher than in the inner bark. However in bark infected by Nectria, phenol levels in the inner bark were significantly higher than in the outer bark.

Pectinasc activities of Nectria ditissima Tul. cause of the Beech canker. In vitro, Nectria ditissima is capable of secreting pectinases necessary for degradation of pectic material of the cell wall. Some pectinascs, ENDOPG, EXOPG and EXOPMG, play a prominent part in degradation of the bark in vivo, their primary participation being affected by the conditions of the bark environment, especially pH. The virulence of four pathogenically different strains of N. ditissima is partly correlated with their ability to produce the pectinace essential for alteration of the bark in vitro.

SUMMARY A gel formulation containing carbendazim and triadimefon completely eradicated infection from scraped or unscraped cankers and none became re-infected. Paint formulations containing mercuric oxide or octhilinone completely eradicated infection from scraped cankers but 30–50% of unscraped cankers receiving these treatments became re-infected. Scraping alone encouraged callus tissue formation but did not greatly reduce infection. Fungicide moved from gels into the wood beneath cankers and persisted there for up to 6 months; movement of fungicide from mercuric oxide or octhilinone paints was minimal. Carbendazim was more effective than thiophanate-methyl and xanthan gum than sodium alginate or alginate ester as fungicide and gel component respectively. Rainfall shortly after treatment probably aided movement of fungicide from gels into the wood but salt formation, by incorporation of acid, did little to improve fungicide performance. Unequivocal assessment of efficacy of canker treatment requires data on canker area changes, movement and persistence of active ingredient in the wood and extent of re-infection after 12 months.

The log of the time interval between inoculation with Nectria galligena in October and the onset of rotting in apples held in air was proportional to the deficit between the temperature of incubation and 25 degrees C, but temperature did not affect the rate of subsequent rot expansion. Rots expanded equally fast whether apples were held in dry or moist air. The quantity of rotted tissue obtained after incubating inoculated apples in atmospheres containing up to 12.5% CO2 increased with increasing concentrations of CO2 greater than 2.5%. The quantity of rotted tissue obtained in apples incubated in 10% CO2 was three times as great as that obtained after incubation in air. The incidence of natural rots was lower in apples stored at 4% CO2 than in those stored in air and rotting increased with increasing concentrations of CO2 higher than 4%. Colonies of N. galligena grew faster on malt agar plates incubated in 5% CO2 than in air, but growth was slower in 10% CO2 than in air. The quantity of benzoic acid per mg hyphae accumulated in developing lesions was similarly related to the CO2 concentrations up to 2.5% but decreased at higher concentrations, and the quantities found in apples stored in CO2 concentrations > 5.0% CO2 were less than in those stored in air.

SUMMARY In a factorialized field trial cells of Bacillus subtilis or phenylmercuric nitrate (PMN) were applied as sprays in autumn to manually defoliated apple trees, cv. Bramley's Seedling, artificially infected with Nectria galligena. Trees were additionally sprayed with dithianon at intervals in May and June or left unsprayed at this time. B. subtilis in conjunction with dithianon, and PMN with dithianon were equally effective in the control of canker over a 2-yr period. Dithianon alone gave some control, as did PMN but B. subtilis was not effective without additional applications of dithianon.

Radially flattened fibres and parenchyma cells, together with buckled and constricted rays were interpreted as a drought ring in Sycamore (Acer pseudoplatanus L.). The damage was dated to late summer of 1972, an exceptional drought year in Scotland. Nectria coccinca (Pers. ex Fr.) Fr. and Verticillium tenerum (Nees ex Pers.) Link (Nectria inventa Pethybridge) were the two organisms found almost exclusively in bark and wood of lesions on stems and branches. These lesions were non perennating and had been formed at the end of the 1972 growing season.

Variability in the pathogcnicity of Nectria ditissima Tul. cause of beech canker. Four mycelial strains of Nectria ditissima Tul. were inoculated into young beeches of two different provenances. The size of bark necrosis was assessed monthly from December to June. The strains can be separated into three groups of aggressiveness according to the size of the necrosis, its persistence and also the hormonal disturbances resulting from pathogenesis. The results reported here suggest a differential interaction between N. ditissima and its host Fagus sylvatica.

summary Fungal colonization of healthy beech (Fogus sylvatica L.) branches was studied by sectioning branch lengths and drying the sections under controlled regimes. Maintaining water saturation prevented any fungal development in the wood, while active mycelium was isolated as soon as 14 days after the start of the drying period. Fungi developing in these sections were naturally established in healthy branches in the field and formed a floristically denned group, dominated by Hypoxylon fragiforme (Scop.) Kickx., H. nummularium Buill.: Fr., Nectria coccinea (Pers.: Fr.) Fr., and Coniophora putaena (Fr.) P. Karst., and also included coelomycete species. This group was obtained independently of position of the branch in the canopy, season of sampling over an 11 -month period, and site, sampling including four sites in south-west Britain and one in the French Pyrenees. Several species in this group are specific or show a preference for beech as a host. Direct observations and isolation from sections with time indicated that whereas most species developed inwards from the bark, H. fragiforme and H. nummularium grew out from pockets within the wood. Each pocket contained a genetically different individual, as revealed by colony morphology and vegetative incompatibility tests. It was established that water content of the wood is the major determinant for the initial development of fungi in the xylem of beech, and that these early colonizers derive from inoculum latent in the healthy, living branches.

Of twenty non-ionic surfactant formulations tested in 1974–75 several were successful as eradicants of overwintering apple mildew as were two ionic materials. The incidence of Nectria canker was increased by sprays applied in October but less so by the same materials applied in January or February when phytoxicity measured in terms of fruit yield was also less. PP 222, a non-ionic surfactant introduced in 1975, proved to be an efficient eradicant of mildew in 1976. Although the yield of fruit from most sprayed trees was greater than from controls, the best mildew eradicants did not produce greatest yields in the same year, perhaps indicating adverse effects of treatments on the trees. However, significantly better yields of fruit obtained in the year following the dormant season eradication of primary mildew, suggest long term beneficial effects of these treatments.

HANLIN, RIcHARD T. (Georgia Expt. Sta., Experiment.) Morphology of Neuronectria peziza. Amer. Jour. Bot. 50(1): 56-66. Illus. 1963.-Swollen tips of vegetative hyphae develop into multicellular, multinucleate ascogonia. Hyphae grow up to form a pseudoparenchymatous ascocarp wall. The ascogonia give rise to ascogenous cells from which croziers and asci form. As the ascocarp develops, an apical meristem produces many cells which are pushed downward and form a compact pseudoparenchyma in the centrum. As the asci form, the cells of the pseudoparenchyma elongate, forming central strands. These disintegrate as the asci grow up among them. Mature asci possess a thickened apical cap but no apical ring; the ascospores have longitudinal striations. The chromosome number is n = 5. The pattern of development resembles the Diaporthe type of Luttrell but is unique in the formation of strands from the pseudoparenchyma. Other characters, however, indicate a closer affinity to Nectria. NECTRIA PEZIZA (Tode ex Fries) Fries has long been considered a typical member of the genus Nectria. It was one of the original 18 species placed in the genus by Fries (1846-49), and has been retained there by most workers since. Seaver (1909a,b) considered it to be the type species of Nectria (sensu Seaver). In a study of Danish species of Nectria, Munk (1957) pointed out that there are 2 different types of centrum structure in members of the genus. One of these types, present in N. cinnabarina (Tode ex Fr.) Fr. and most other species studied by him, contained "apical paraphyses" (pseudoparaphyses) which descended from the apex of the ascocarp to its base. The second type of centrum, found in N. peziza, consisted of pseudoparenchyma, with pseudoparaphyses lacking. Correlated with centrum structure was ascospore ornamentation; species possessing pseudoparenchyma had longitudinally striate ascospores, whereas species with pseudoparaphyses had non-striate ascospores. Munk erected the new genus Neuronectria to accommodate those species having central pseudoparenchyma and striate ascospores. Neuronectria peziza (Tode ex Fr.) Munk (= Sphaeria peziza Tode ex Fr.) was designated as the type species. The genus Nectria was restricted to those forms having pseudoparaphyses and non-striate ascospores. A detailed study of ascocarp development in the type species, Neuronectria peziza, has been carried out and the results compared with previous studies in the genus Nectria. MATERIALS AND METHODS-The specimen used in this study was isolated from deer dung collected in Maine by Dr. L. E. Wehmeyer during the summer of 1959. Perithecia appeared after

HANLIN, RICHARD T. (Georgia Experiment Station, Experiment.) Studies in the genus Necwria. II. Morphology of N. gliocladioides. Amer. Jour. Bot. 48(10): 900-908. Illus. 1961.-Swollen tips of vegetative hyphae develop into multicellular archicarps from which multinucleate ascogonia forrn. From basal cells of each archicarp arise hyphae which grow up into a prosenchymatous, true perithecial wall; around this wall is formed a thin pseudoparenchymatous stroma of compacted hyphae. The ascogonia give rise to ascogenous cells from which croziers and asci form directly. At the same time, an apical meristem forms cells that grow downward into the centrum. These are pseudoparaphyses. Asci grow up among the pseudoparaphyses, which deliquesce as the ascocarp matures. The ascus tip contains a thick ring with a pore and lateral thickening of the ascus wall. Ascospores are forcibly ejected. The chromosome number is 4. This species conforms to the Nectria Developmental Type of Luttrell. THE TAXONOMIC position of those Pyrenomycetes having brightly colored, fleshy ascocarps has been variouslv interpreted by different workers. Some (Lindau, 1897; Gaumann, 1926; Bessey, 1950; Miller, 1949; Luttrell, 1951) have placed them in a separate order, the Hypocreales, while others (Miller, 1928; Clements and Shear, 1931; Gaumann, 1952; Von Arx and Muller, 1954; Munk, 1957), not considering color and texture sufficient basis for separation, included them in the Sphaeriales in one or more families. In recent years, developmental data have become increasingly important in taxonomic arrangements. In 1951, Luttrell proposed a system based on types of development of the ascocarp. He recognized 8 different developmental patterns, 1 of which, the Nectria Developmental Type, served as the basis for the order Hypocreales. The extent of this developmental type among hypocreaceous fungi can be determined only by detailed studies of the different species. The few studies which have been carried out are mostly incomplete and, therefore, of little value in determining the position of these fungi in a taxonomic system based on developmental morphology. The genus Nectria is a good example of this. Of the 4 species studied previously (N. ribis Tode ex Rab. [Vincens, 1917]; N. galligena Bres. 1 Received for publication May 10, 1961. Paper No. 1121, Department of Botany, University of Michigan; and Paper No. 397, Journal Series, Georgia Experiment Station. This research was supported in part by National Science Foundation Grant G-10727. Portion of a dissertation submitted to the faculty of The University of Michigan in partial fulfillment of the requirements for the degree of Doctor of Philosophy. I am grateful to Dr. L. E. Wehmeyer for his guidance during this study and for reviewing the manuscript. [Cayley, 1921]; N. ipomoeae Halst. [Cook, 1923]; N. flava Bon. [Gilles, 1947]), only the work on N. flava approaches the detail necessary for modern taxonomic work. The present study was conducted to determine the position of N. gliocladioides Smalley & Hansen on the basis of its development. MATERIALS AND METHODS-Nectria gliocladioides was originally isolated from decaying bulbs of Lilium auratum Lindl. (Smalley and Hansen, 1957). The material used in this study was derived from a culture obtained from Dr. E. B. Smalley. Cultures were grown on complete mineral-medium agar plates containing 2% glucose under continuous fluorescent ("Daylight") light at 25 C. Suitable material was cut up into blocks approximately 5 mm2, then killed and fixed in Allen-Bouin Solution, Type II (Sass, 1951). Dehydration was carried out bv means of the tertiary butyl alcohol (TBA) method (Sass, 1951). Embedding was done in Fisher Tissuemat (mp 54-56 C). Sections were cut at a thickness of from 8 to 10 u, the ribbons were floated on a 3% solution of formaldehyde in distilled water, and affixed to the slides with Haupt's Adhesive (Johansen, 1940). A number of stains were tried but the majority gave poor results. The method finally selected was a modification of that used by Robinow (1957). Sections were stained with the Feulgen technique (Johansen, 1940), then counterstained in 0.5% acetocarmine (45% acetic acid). Optimum time for both hydrolysis and counterstaining was 3 min. A longer time intensified the stain too much, obscuring detail. Studies of asci were made with fresh material. Squash mounts were made in 1 % acetoorcein (60% acetic acid) or 1% acetocarmine Fig. 1-13. All magnifications X 1700 unless otherwise stated.-Fig. 1. Typical Gliocladium conidiophore.-Fig. 2. Typical Verticillium conidiophore. X 850.-Fig. 3-4. Conidiophores intermediate in structure. X 850.-Fig. 5, left to right. Stages in conidial development, from branch to mature conidium. X 3000.-Fig. 6. Two mature conidia.-Fig. 7. Two conidia germinating after 6 hr in distilled water.-Fig. 8. Three mature ascospores, 2 with germ tubes after 6 hr.Fig. 9. Germinating conidium after 10 hr.-Fig. 10-12. Germinating ascospores after 14 hr.-Fig. 13. Tip of mature ascus showing wall thickening and apical ring with pore. X 3000.

Twenty-seven species of freshwater Hyphomycetes from two five-state areas in the northern Appalachian Highland, New England, and three Coastal Plain states were collected, isolated, and identified. The spores of three fungi which are probably aquatic Moniliales were also studied. Sigmoidea, a new Hyphomycete genus, includes submerged aquatic fungi which produce phialides laterally along the mycelium and sigmoid, multicellular phialospores. Varicosporium giganteum sp. n. produces terminal, hyaline, branched, and multiseptate aleuriospores. The main spore axis has one to four lateral branches which arise successively on one side of this axis. Tricladium marylandicum sp. n. is similar to T. splendens in that the lateral branches are constricted where each branch joins the main spore axis. It differs from this species in that the spore has a blunt apical cell on the main avis and on each of the lateral axes. Three possible methods of dispersal are presented to explain the cosmopolitan distribution of freshwater Hlyphomycetes. FRESHWATER HYPHOMYCETES are a very specialized group of conidial fungi which usually occur on partially decayed, submerged leaves of angiosperms, a fact demonstrated by Ingold (1942). Their spores are also found in the surface foam of most lakes, rivers, and streams. Ingold also observed that these hyphomycete spores develop and are liberated under water and that either the spores or the mycelia can be cultured on malt extract agar. He noted that the tetra-radiate and the sigmoid spore-type predominate in the group, and because of this he postulated that these spores may be uniquely suited for dispersal in the aquatic habitat; the unusual spore morphology probably aids their entanglement in a substrate suitable for growth. The first comprehensive study of the North American freshwater Hyphomycetes was undertaken by Ranzoni (1953), who reported 22 species from California of which 5 were new. Umphlett (1957) found 13 species in Virginia. Petersen (1960, 1962, 1963a, b) surveyed North America; he reported more than 30 species, 10 previously 1 Received for publication 27 March 1968. Scientific Article No. A1390, Contribution No. 3991 of the Marvland Agricultural Experiment Station. A portion of a thesis submitted in partial fulfillment of the requirement for the degree of Doctor of Philosophy, University of Maryland. The author is indebted to Dr. Robert A. Paterson, Department of Biology, Virginia Polytechnic Institute, for his guidance in the course of this study, and to the personnel of the American Type Culture Collection, Rockville, Md., for the use of laboratory space and equipment, and for preserving the cultures. This work was partially supported by National Science Foundation Grant No. GB2703. 2 Present address: Illinois Natural History Survey, Urbana, Illinois 61801. undescribed. The aquatic Hyphomycetes are now represente.d the world over by approximately 70 species in 38 genera. The ascogenous state of five species has been found. The first was observed by Ranzoni (1956), who discovered the perfect state of Flagellospora penicillioides Ingold, which he described as Nectria penicillioides. Later, Webster (1959, 1961, 1965) related the conidial state of three aquatic Hyphomycetes to their perfect states. Perithecia obtained in cultures of single-spore conidial isolates of Heliscus lugdunensis Sacc. & Therry provided the bases for the description of Nectria lugdunensis Webster. Later, a Discomycete was obtained from multispore isolates of Anguillospora crassa Ingold. Apothecia of these fungi were characteristic of a Mollisia, and no attempt was made to describe the species. Finally, cultures of a Pyrenomycete growing on decorticated branches of Alnus glutinosa (L.) Gaertn. produced the conidia of Dactylella aquatica (Ing.) Ranzoni, and Webster described this as Massarina aquatica. Recently, Tubaki (1966) collected twigs with several apothecia of Hymenocyphus varicosporoides Tubaki; the colonies resulting from single ascospore isolates, when submerged in water, produced the conidia of an undescribed species of Varicosporium. This paper presents the distribution of 27 species of freshwater Hyphomycetes in two fivestate areas of the northern Appalachian Highland including New England and three Coastal Plain states. One new genus and two new species are described, and the mature spores of three probable aquatic Hyphomycetes are also discussed. In addition, the role of waterfowl, the possibility of an alternate terrestrial conidial

Several isolates fromg Canada and Europe of Nectria fuckeliana var. fuckeliana and of N. fuckeliana var. macrospora were compared physiologically, morphologically, and in their ability to cause cankers on Abies species. As a result, it is proposed to raise these varieties to species level, that is, Nectria fuckeliana and N. macrospora. Isolates of N. macrospora from Quebec were found to be much more virulent than the other isolates studied.

A B S T R A C T The cytology of ascus development in Nectria cinnabarina was investigated with the orceinsmear technique, from crozier formation to ascospore maturation. At prophase I synapsis occurs while the chromosomes are still contracted, and the nucleus passes through dictyotene, a diffuse stage rarely seen in plants. A haploid complement of five chromosomes has been precisely determined. The first two divisions in the ascus constitute meiosis, and the third (mitotic) is followed by ascospore delimitation. A fourth division takes place in the ascospore, which is subsequently divided by a septum into two uninucleate cells. Of all species of Nectria thus far investigated N. cinnabarina is the only species in which additional nuclear divisions in the ascus do occur, accounting for the multinucleate condition in the ascospore cells. The bearing that this distinctive nuclear condition has on phylogeny and evolution in the Hypocreales is discussed. IN THE WAKE of a controversy related to sex determination and chromosome numbers in the ascomycete Hypomyces solani2 Rke. et. Berth. emend. Snyd. et Hans. (Hirsch, 1949; El-Ani, 1954), a series of cytological studies was undertaken for three main purposes. First, to determine the haploid chromosome number(s) in wild-type and mutant strains of H. solani f. cucurbitae Snyd. et Hans. Second, to find out whether a polyploid relationship does exist between homothallic and heterothallic strains as reported by Hirsch (1949).

Nectria ascospores discharged from a Beech bark diseased tree were monitored by a spore trap, and prevailing meteorological conditions were recorded. Forest and glasshouse experiments are described in which necrosis of beech bark followed wound inoculation with Nectria isolates during dormancy. Perithecia were produced in vitro and spore dimensions were measured. Linear growth rate of the fungus in culture was compared over a range of temperatures.