Check-list for scientific names of common parasitic fungi. Supplement Series 2b (additions and corrections): Fungi on field crops: Cereals and grasses

This paper suplements Series 2b (Neth. J. Pl. Path. 83 (1977) 165–204) and documents the nomenclature of an additional 10 parasitic fungi. The data on 25 fungi (teleomorph and/or anamorph) previously treated in Series 2b have been brought up to date and in accordance with the recent changes in the International Code of Botanical Nomenclature. The selected names include one new variety and two new infraspecific combinations, viz.Tapesia yallundae var.acuformis Boerema et al., anam.Ramulispora herpotrichoides var.acuformis (Nirenberg) Boerema et al. andUstilago tritici (Pers.) Rostrup f. sp.hordei (Schaffnit) Boerema et al.     

Check-list for scientific names of common parasitic fungi. Supplement Series 2c,d (additions and corrections): Fungi on field crops: pulse (legumes), forage crops (herbage legumes), vegetables and cruciferous crops

This supplement to Series 2c (Neth. J. Pl. Path. 85 (1979) 151–185) and Series 2d (Neth. J. Pl. Path. 86 (1980) 199–228) includes 12 pathogens not treated before. The data of 30 other pathogenic fungi have been revised or emended and brought in accordance with the present Code of Botanical Nomenclature. One new variety and two new combinations are proposed, viz.Phoma medicaginis var.macrospora Boerema et al.,Phoma boltshauseri (Sacc.) Boerema et al. andPeronospora viciae (Berk.) Casp. f.sp.fabae (Jacz. & Serg.) Boerema et al.     

Check-list for scientific names of common parasitic fungi. Supplement Series 2a (additions and corrections): Fungi on field crops: Beet and potato; caraway,flax and oil-seed poppy

This paper supplements Series 2a (Neth. J. Pl. Path. 82 (1976) 193–214) and documents the nomenclature of an additional four parasitic fungi. The data of sixteen fungi (teleomorph and/or anamorph) previously treated in Series 2a have been brought up to date and in accordance with the recent changes in the International Code of Botanical Nomenclature (‘Sydney Code’). One new combination is proposed, viz.Uromyces beticola (Bellynck) Boerema et al. The scientific names used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture and Fisheries conform with those selected in the check-list.     

Check-list for scientific names of common parasitic fungi. Series 3b: Fungi on bulbs: Amaryllidaceae and Iridaceae

This list is a continuation of Series 3a (Neth. J. Pl. Path. 94 (1988), Supplement 1), an account of the nomenclature of common parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture and Fisheries. The selected names include one new species,Curvularia gladioli Boerema & Hamers, one new pathogenic form,Fusarium oxysporum f.sp.croci Boerema & Hamers, and one new combination,Sclerotium narcissi (Sacc.) Boerema & Hamers.A contribution towards the costs of publication provided by the Landbouw Export Bureau Fund, Wageningen, is gratefully acknowledged.     

Check-list for scientific names of common parasitic fungi. Series 3b: Fungi on bulbs: Amaryllidaceae and Iridaceae

This list is a continuation of Series 3a (Neth. J. Pl. Path. 94 (1988), Supplement 1), an account of the nomenclature of common parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture and Fisheries. The selected names include one new species,Curvularia gladioli Boerema & Hamers, one new pathogenic form,Fusarium oxysporum f.sp.croci Boerema & Hamers, and one new combination,Sclerotium narcissi (Sacc.) Boerema & Hamers.     

Check-list for scientific names of common parasitic fungi. Series 3a: Fungi on bulbs: Liliaceae

This list gives a first account on the nomenclature of common parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture and Fisheries. The selected names include one new species,Colletotrichum lilii Plakidas ex Boerema & Hamers, and four new combinations:Botrytis convallariae (Kleb.) Ond?ej ex Boerema & Hamers,Puccinia sessilis Schneid. ex Schröt. f. sp.convallariae-digraphidis (Kleb.) Boerema & Hamers and f. sp.smilacearum-digraphidis (Kleb.) Boerema & Hamers, andSclerotium rolfsii var.delphinii (Welch) Boerema & Hamers.     

Check-list for scientific names of common parasitic fungi. Series 3c: Fungi on bulbs: ‘additional crops’ belonging to the Araceae,Begoniaceae, Compositae,Oxalidaceae and Ranunculaceae

This list is a continuation and also the ending of Series 3a and 3b [Neth. J. Pl. Path. 94 (1988), Supplement 1 and 95 (1989), Supplement 3], an account of the nomenclature of parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture, Nature Management and Fisheries. The ‘additional crops’ subject to this Series 3c do not refer to bulbs in the common sense, but come within the present Dutch definition of ‘Bolgewassen’. The selected names include one new species (anamorph):Entylomella dahliae Ciferri ex Boerema & Hamers.     

Polymorphism of 14α-demethylase Gene (CYP51) in the Cereal Eyespot Fungi Tapesia acuformis and Tapesia yallundae

Cereal eyespot fungi Tapesia acuformis and Tapesia yallundae are closely related species which show different behaviours upon treatment with sterol 14-demethylase inhibitors (DMIs). T. acuformis is naturally resistant to DMIs belonging to the triazole family and susceptible to the imidazole ones, whilst T. yallundae is sensitive to both inhibitors. Cloning of the target enzyme gene, CYP51, from the two species revealed an important polymorphism between them. Further sequencing of CYP51 from sixteen T. acuformis and eleven T. yallundae strains with different phenotypes with regards to resistance to DMIs confirmed that at least eleven variations are species related. Among them, a conserved phenylalanine residue at position 180, found both in T. yallundae and in all known CYP51 proteins from filamentous fungi and yeast, was replaced in T. acuformis by a leucine. Therefore, a leucine at 180 could be possibly involved in natural resistance of T. acuformis to triazoles. Other mutations were observed in some resistant strains, sometimes simultaneously, but in contrast to what was reported for other filamentous fungi, where a mutation at the 136 position of the CYP51 gene product seemed to correlate with resistance to DMIs, we did not find a clear relationship between a given mutation and a particular phenotype. This result suggests that resistance to DMIs could have a polygenic nature in Tapesia. We took advantage of species-related variations to develop a PCR-based assay allowing rapid and easy discrimination between field strains of the two species.     

Resistance to Oculimacula yallundae and Oculimacula acuformis is conferred by Pch2 in wheat

The recent report of a differential response of wheat lines containing the Pch2 gene to infection with the eyespot pathogens Oculimacula yallundae and O. acuformis has prompted this re‐examination of the response to these fungi by the recombinant lines used to map Pch2. Homozygous recombinant substitution lines (RSL) derived from the hybridization of Chinese Spring (CS) and the CS chromosome substitution line Cappelle Desprez 7A (CS/CD7A), previously evaluated for response to glucuronidase (GUS)‐transformed O. yallundae, were evaluated for response to infection with GUS‐transformed O. acuformis. Based on visual scores and on GUS expression level, which reflects fungal colonization of seedling plants, evidence of a quantitative trait locus (QTL) conferring resistance to O. acuformis was found in two separate growth chamber experiments (logarithm of the odds, LOD, = 2·7 and 6·7 at 305 and 289 cM, respectively) that was equivalent in location to that for resistance to O. yallundae (LOD = 13·2 and 11·4 at 289 and 304 cM, respectively). These results confirm that Pch2 confers some degree of resistance against both O. yallundae and O. acuformis under these conditions.     

Check-list for scientific names of common parasitic fungi. Series 3c: Fungi on bulbs: ‘additional crops’ belonging to the Araceae, Begoniaceae, Compositae, Oxalidaceae and Ranunculaceae

This list is a continuation and also the ending of Series 3a and 3b [Neth. J. Pl. Path. 94 (1988), Supplement 1 and 95 (1989), Supplement 3], an account of the nomenclature of parasitic fungi on bulbs as used in official publications of the Netherlands Society of Plant Pathology and the Netherlands Ministry of Agriculture, Nature Management and Fisheries. The additional crops subject to this Series 3c do not refer to bulbs in the common sense, but come within the present Dutch definition of Bolgewassen. The selected names include one new species (anamorph):Entylomella dahliae Ciferri ex Boerema & Hamers.Dit is een vervolg op Serie 3a en Serie 3b (Boerema en Hamers, 1988, 1989), waarin de naamgeving werd behandeld van de parasitaire schimmels bij de bekende bloem-bollen-en bolbloementeeltgewassen, behorende tot respectievelijk de Liliaceae, Amaryllidaceae en Iridaceae. De bijgoedgewassen waarvan nu in dit slotdeeltje de parasitaire schimmel-naamgeving wordt besproken, zijn geselecteerd uitgaande van het door het Laboratorium voor Bloembollenonderzoek te Lisse gepubliceerde handboek Ziekten en afwijkingen bij bolgewassen, deel 2, 1978. Tot de geselecteerde namen behoort één nieuwe soort (anamorf):Entylomella dahliae Ciferri ex Boerema & Hamers. In de officiële publikaties van de Nederlandse Planteziektenkundige Vereniging en het Ministerie van Landbouw, Natuurbeheer en Visserij zullen de namen van de check-list-serie worden gebruikt.     

Fungicide resistance status in French populations of the wheat eyespot fungi Oculimacula acuformis and Oculimacula yallundae

Eyespot, caused by Oculimacula acuformis and Oculimacula yallundae, is the major foot disease of winter wheat in several European countries, including France. It can be controlled by chemical treatment between tillering and the second node stage. The fungicides used include antimicrotubule toxicants (benzimidazoles), inhibitors of sterol 14α‐demethylation (DMIs) or of succinate dehydrogenase (SDHIs), the anilinopyrimidines cyprodinil and the benzophenone metrafenone. Since the early 1980s, a long‐term survey has been set up in France to monitor changes in the sensitivity of eyespot populations to fungicides. Resistance to benzimidazoles has become generalised since the early 1990s, in spite of the withdrawal of this class of fungicides. In the DMI group, resistance to triazoles is generalised, whereas no resistance to the triazolinethione prothioconazole has yet developed. Resistance to the imidazole prochloraz evolved successively in O. acuformis and O. yallundae and is now well established. Specific resistance to cyprodinil has also been detected, but its frequency has generally remained low. Finally, since the early 2000s, a few strains of O. yallundae displaying multidrug resistance (MDR) have been detected. These strains display low levels of resistance to prothioconazole and SDHIs, such as boscalid. Knowledge of the spatiotemporal distribution in France of O. acuformis and O. yallundae field strains resistant to fungicides allows resistance management strategies for eyespot fungi in winter wheat to be proposed.© 2012 Society of Chemical Industry     

Comparative study of morphological,cultural and molecular markers for the characterization ofPseudocercosporella herpotrichoides isolates

Nirenberg's classification system and the polymerase chain reaction (PCR) combined with restriction enzyme digestion of an amplified ribosomal DNA fragment, were compared for the characterization of sixty isolates ofPseudocercosporella herpotrichoides, from various geographical areas and with differing fungicide sensitivity. With Nirenberg's system, it was possible to identify most isolates asP. herpotrichoides var.herpotrichoides orP. herpotrichoides var.acuformis. However, identification was slow and sometimes inconclusive as overlap occurred between the two varieties for all criteria examined. Molecular markers identified two distinct types among the isolates tested and generally good correlation was found between the PCR-based assay and Nirenberg's system, but the molecular assay was more accurate and faster.     

Re-infection by Erwinia carotovora (Jones) Bergey et al. in Potato Stocks derived from Stem Cuttings1

Propagation of potato stocks by the stem cutting method has produced crops almost entirely free from infection with the soft rot coliform bacteria, Erwinia carotovora (Jones) Bergey et al var. atroseptica (Hellmers et Dowson) Dye and E. carotovora var. carotovora Dye. However, low levels of re-infection have occurred and evidence indicates that a source of the organisms was infected insects. Air-borne spread of bacterial aerosols generated by raindrop impaction on infected stems might also result in healthy stocks becoming re-infected.     

Nomenclatural remarks on three plant parasitic fungi

Discella salicis (Westend.) Boerema is a new combination proposed for the connidial state ofCryptodiaporthe salicella (Fr.) Petr. (branch canker of willow) to replace the misapplied nameDiscella carbonacea (Fr. ex Fr.) Berk. & Br. The new combinationMycosphaerella pyri (Auersw.) Boerema is proposed for the perfect state ofSeptoria pyricola (Desm.) Desm. (leaf fleck of pear) to be used instead of of the misapplied nameMycosphaerella sentina (Fr.) Schroet. The nameMelampsoiridum betulinum (brich rust) is attributable to Klebahn alone; and not as being based on earlier names from Persoon, Fries, Tulasne or Desmazières.Samenvatting Voorgesteld is het imperfecte stadium vanCryptodiaporthe salicella (Fr.) Petr., de veroorzaker van schorsbrand bij wilg, aan te duiden met de nieuwe combinatieDiscella salicis (Westend.) Boerema, ter vervanging van de onjuist toegepaste naamDiscella carbonacea (Fr. ex Fr.) Berk & Br. Voor het perfecte stadium vanSeptoria pyricola (Desm.) Desm., veroorzaker van een bladvlekkenziekte bij peer, is de nieuwe combinatieMycosphaerella pyri (Auersw.) Boerema geïntroduceerd, in plaats van de onjuist. toegepaste naamMycosphaerella sentina (Fr.) Schroet. Verder werd vastgesteld dat Klebahn moet worden beschouwd als de enige auteur van de berkenroestMelampsoridium betulinum     

Check-list for scientific names of common parasitic fungi

An antibiotic substance, MYC 8005, was found to be produced by aStreptomyces strain, D197. It proved to possess strong antibiotic activities against bacteria, fungi and spider mites. It might be similar to antibiotic 323/58 reported in 1962 by Kruglyaket al. This antibiotic, however, is no longer available for comparison. The producing organism resmblesStreptomyces exfoliatus (Waksman & Curtis) Waksman & Henrici but differs from this species in the surface structure of the spores. For this reason it is proposed to give D 197 the nameStreptomyces exfoliatus var.echinosporus var. nov. The nature of the symptoms observed with spider mites and the susceptibility of various acaricide-resistant strains to this antibiotic suggest a new mode of action.     

Commonwealth Agricultural Bureaux First Commonwealth Helminthological Meeting

Abstract

Fourteen of the 62 taxonomically characterized viruses known to infect peanuts naturally or under experimental conditions are potyviruses (Sreenivasulu et al. 1991). Peanut stripe potyvirus (PStV) was first noted in 1982 when virus‐like leaf symptoms were observed on peanut in plots in Georgia (USA) that seemed different from those of the endemic peanut mottle potyvirus (Demski and Lovell, 1985). Demski et al. (1984a,b,c) reported it to be a new virus disease of groundnut (Arachis hypogaea L.) characterized by dark green stripes and discontinuous banding along the lateral veins of young leaves and an oakleaf pattern on the older leaves. The virus was detected in germplasm received from China (Demski et al. 1984a,b,c; Demski and Lovell, 1985). PStV is now known to occur in most of the south‐east Asian countries growing groundnut including India (Prasada Rao et al., 1988a). The virus is reported to be seedborne and transmitted by species of aphids. It has assumed considerable quarantine importance throughout the world. Much scientific information has been generated and published on various aspects of PStV, but the information is scattered. This paper reviews research on peanut stripe disease and considers future priorities and control strategies.     

Evolution of fungicide resistance in the cereal eyespot fungi Tapesia yallundae and Tapesia acuformis in France

Field isolates of the cereal eyespot pathogen can be divided into two groups which are now considered as two species: Tapesia yallundae and Tapesia acuformis. In both species the first case of acquired resistance was observed with benzimidazole fungicides in the early 1980s. At the same time, a number of sterol C-14 demethylation inhibitors (DMIs), such as the imidazole prochloraz and several triazoles, including flusilazole, were introduced. Surprisingly T. acuformis appeared intrinsically resistant to the triazole derivatives in comparison to T. yallundae, but both species were sensitive to prochloraz. The intensive use of these DMIs led to the development of acquired resistance towards triazoles in T. yallundae and towards prochloraz in T. acuformis. Today all the strains in both species appear equally sensitive to the anilinopyrimidine cyprodinil. ©1997 SCI     

Differential seedling resistance to the eyespot pathogens,Oculimacula yallundae and Oculimacula acuformis,conferred by Pch2 in wheat and among accessions of Triticum monococcum

Eyespot is an economically important stem‐base disease of wheat caused by two fungal species: Oculimacula yallundae and Oculimacula acuformis. This study investigated the efficacy of two sources of resistance, viz. the genes Pch1, introgressed into hexaploid wheat from Aegilops ventricosa, and Pch2, identified in wheat cv. Cappelle Desprez, against O. yallundae and O. acuformis separately. In a series of seedling bioassays Pch1 was found to be highly effective against both species. Although Pch2 was found to confer resistance against both pathogen species, it was significantly less effective against penetration from O. yallundae than O. acuformis. Furthermore, a quantitative trait locus (QTL) analysis was not able to locate any resistance to O. yallundae on chromosome 7A of Cappelle Desprez. This has important implications for the use of Pch2 in commercial cultivars as it is necessary to have genes that confer resistance to both pathogens for effective eyespot control. In addition, a set of 22 T. monococcum accessions was screened for resistance to both O. yallundae and O. acuformis to identify potentially novel resistances and to assess the accessions for evidence of differential resistance to the eyespot species. Significant differences in resistance to the two pathogens were identified in four of these lines, providing evidence for differential resistance in T. monococcum. This study demonstrates that future screening for novel sources of eyespot resistance should investigate both pathogen species.     

New Cases of Negative Cross-resistance between Fungicides,Including Sterol Biosynthesis Inhibitors

A survey of fungicide resistance in Mycosphaerella graminicola and Tapesia acuformis, two major pathogens of winter wheat in France, respectively responsible for speckled leaf blotch and eyespot, led to the characterization of two types of resistant strains to sterol 14α-demethylation inhibitors (DMIs). Most of the strains of M. graminicola collected in France in 1997–1998 were resistant to all DMIs, and only in a few strains was the resistance to several triazoles associated with increased susceptibility to pyrimidine derivatives (i.e., fenarimol, nuarimol) and triflumizole. On the other hand, in T. acuformis the most prevalent strains were those which exhibited negative-cross resistance between DMIs. In both fungi such a phenomenon could be related to changes in cytochrome P450 sterol 14α-demethylase, the target site of these fungicides. For Botryotinia fuckeliana, the causal agent of grey mould, the extensive monitoring conducted in French vineyards before the marketing of fenhexamid revealed the presence of highly resistant strains to this promising botryticide (only in tests involving mycelial growth measurements). Negative cross-resistance to edifenphos and several sterol biosynthesis inhibitors, such as prochloraz and fenpropimorph, was observed in fenhexamid resistant strains. Synergism of the antifungal action of fenhexamid by cytochrome P450 inhibitors, such as the DMI fungicides, was only recorded in fenhexamid resistant strains. These data and those previously obtained with edifenphos resistant strains of Magnaporthe grisea (rice blast pathogen) suggest that in fenhexamid resistant strains of B. fuckeliana the same cytochrome P450 monooxygenase could be involved in detoxification of fenhexamid and activation of edifenphos. Received 6 September 1999/ Accepted in revised form 13 September 1999     

Biological Control of Take-all by Phialophora radicicola Cain1

Biological control of take-all by Phialophora radicicola Cain and similar fungi is reviewed, and new evidence is presented on the possible role of hyper-parasites, like Pythium oligandrum Drechsler, to augment this. Phialophora radicicola var. graminicola Deacon is abundant in British grasslands. Its role in biological control of take-all has been demonstrated in the glasshouse with natural soils and natural population levels of this control agent. Also there is much circumstantial evidence for its beneficial role in agriculture, especially in cereal monoculture following grass crops, and in natural and amenity grasslands. Some other similar fungi control take-all in the glasshouse, but their roles in current agricultural practice are not known. The take-all fungus, itself, can reduce infection of roots by P. radicicola, so there is a dynamic interaction between these fungi. This is affected by host type, relative inoculum potentials of the fungi, and possibly by environmental conditions. By careful manipulation, therefore, it might be possible to control take-all under a wide range of field conditions. The chief role of P. radicicola and similar fungi is to delay establishment of severe take-all early in cereal monoculture, rather than to combat an existing high disease level. It may therefore be desirable to combine different biocontrols, and hyperparasites like Pythium oligandrum may be important in this respect. This fungus was tested against varieties of Gaeumannomyces graminis Arx & Olivier and Phialophora radicicola in the laboratory; the host responses differed greatly, from marked susceptibility (P. radicicola var. radicicola) to almost complete resistance (G. graminis var. graminis). Hence, P. oligandrum might be used to alter relative population levels of these fungi in the field, but first its behaviour in natural soils must be studied.