Phomopsis Species Research Articles

Variation in Phomopsis Recorded on Grapevine in Australia and Its Taxonomic and Biological Implications

Phomopsis viticola is the cause of cane and leaf blight of grapevines. We examined 63 isolates obtained from a survey of 50 vineyards in New South Wales, Victoria, South Australia, Western Australia and Tasmania, from collections in the New South Wales Agriculture Plant Pathology Herbarium, and from vine specimens from a further 36 vineyards. Two distinct taxa (Taxa 1 and 2) of Phomopsis were found, based on alpha spore morphology, appearance of the pycnidium, cirrhus colour, rate of mycelial growth and sporulation in vitro. Minor taxa (Taxa 3 and 4) were found also. Of the isolates studied, 26 were of Taxon 1 and 33 of Taxon 2. Taxon 1 occurred predominantly in coastal vineyards and Taxon 2 in inland vineyards. Studies of isolates representing the different taxa indicated variability in host response, pectic enzyme profile and temperature for optimum spore germination. These criteria confirmed the morphological grouping of the isolates. Isolates DAR 69489, DAR 69457, DAR 69458 and DAR 69484 were designated as representative isolates of Taxa 1, 2, 3 and 4, respectively. Taxon 1 fits the current taxonomic description of Phomopsis viticola (Sacc.) Sacc. Taxon 2 may resemble the species named Fusicoccum viticolum Reddick, or be a variety of P. viticola (Sacc.) Sacc. or a distinct species of Phomopsis. The widespread occurrence of Phomopsis in Australia and the presence of different taxa in the different viticultural regions are demonstrated.

Nuclear ribosomal internal transcribed spacer phylogeny and host diversity in the coelomycete Phomopsis

Species concepts in Phomopsis are based primarily on host association because morphological and cultural characters are generally insufficient for species diagnosis. Increasingly, there are reports that some species of Phomopsis are not host restricted but are capable of infecting several or more taxonomically unrelated host genera. Phylogenetic analysis of nuclear ribosomal DNA internal transcribed spacer sequences (ITS1 and ITS2) for 43 North American and Caribbean strains of Phomopsis isolated from diverse plant hosts and geographic origins resolved three clades, provisionally termed groups A, B, and C. Group A consists of isolates from shrubs and trees originating primarily from eastern North America. Group B includes isolates from woody and herbaceous plants that originate from tropical to subtropical regions and produce paraphyses among their conidiogenous cells. Group C occurs primarily on herbaceous plant hosts, including agricultural field crops, and is widely distributed throughout temperate to subtropical North America. Isolates from Europe and Asia may be significantly different in ITS sequences compared with North American isolates. The diversity of host taxa associated with terminal clades in the ITS phylogeny suggests that either Phomopsis species infect more than one host or host switching occurs frequently during speciation. Key words: Ascomycotina, coelomycetes, Diaporthe, ITS, molecular phylogeny, Phomopsis.

Fungal endophytes from the leaves and twigs of Quercus ilex L. from England, Majorca and Switzerland.

Leaves of Quercus ilex taken from sites in England, Majorca and Switzerland have been studied to detect the influence of the geographic position of the host within and outside its native range on the composition of its endophytic fungal assemblages. Samples of stem tissue of Q. ilex collected from the Swiss trees were also studied to confirm tissue-specific differences. Sixty different fungal taxa were isolated, but only 28 were frequent. Of the total number of isolates from the leaves from the Swiss, British and Spanish sites 87%, 31% and 63%, respectively, were coelomycetes. Four species of Phomopsis, which includes Phyllosticta ilicina (=Phomopsis ilicina v. d. Aa, ined.), were the most frequent endophytes of leaves and were either absent or rare in the twig units. Two distinct kinds of sterile mycelia were common in twigs. Swiss and Spanish trees possessed fungal assemblages distinct from those present in Britain. Naturalized stands were distinguished from native stands by the presence of rather cosmopolitan and non-specific fungal taxa, rare or absent in the samples collected in the native stands. Samples derived from the native stands were colonized by more host-specific fungi. The relative frequency of two sterile mycelia in the Swiss and Spanish sites determined their separation. Phyllosticta (Phomopsis) ilicina, the most numerous leaf colonizer, was virtually absent from the bark and the xylem. The frequent occurrence of coelomycetes as endophytes of woody trees is briefly discussed.

Phomopsis of sunflower in the ukraine and the development of breeding methods for resistance

Information on the structure of the population of Phomopsis species in Ukraine, that describes the structure of Phomopsis spp. cultivated on medium: the morfological characteristics, properties of pathogenicity and phytotoxicity. It is described the method of evaluation and selection of unsusceptible forms of sunflower to phomopsis. It includes the optimal infection level, the forms of an inoculum that is effective and optimal way for artificial infection.

Sclerotinia and Phomopsis — two devastating sunflower pathogens

Cultivated sunflower (Helianthus annuus L.) is prone to many diseases caused by fungi, bacteria, and viruses, of which the most detrimental are those caused by fungi. Two of the most important fungal pathogens are Sclerotinia and Phomopsis. Within the genus Sclerotinia, both S. minor and S. sclerotiorum cause a basal stalk rot and subsequent wilt of sunflower, with S. sclerotiorum more widely distributed around the world. Sclerotinia sclerotiorum also incites a head rot and mid-stem rot of sunflower. Since Sclerotinia spp. have a very wide host range and can persist in soil as dormant sclerotia for up to 10 years, the pathogens have been extremely difficult to control with either generic resistance or fungicides. The most effective control is the use of long rotations, tolerant hybrids, and sclerotium-free seed. Gray stem spot is a relatively new disease of sunflower first observed in the early 1980s in Yugoslavia and now considered the most devastating sunflower disease in eastern Europe. Symptoms include large stem cankers and subsequent wilt. Phomopsis helianthi has been identified as one incitant of gray stem spot, but another Phomopsis species may also be involved, both in Europe and in the United States. Foliar fungicides can control gray stem spot, but the development of resistant hybrids has been much more cost-effective.

Post-harvest diseases of avocado fruits in New Zealand

Abstract Two major post-harvest diseases have been found in New Zealand avocados (Persea americana Miller): anthracnose, associated with Colletotrichum species, and stem-end rots, associated with Botryosphaeria and Phomopsis species. Several Fusarium species have been also isolated from fruit rots. Scab (Sphaceloma perseae Jenkins) is recorded for the first time on New Zealand avocados.

Morphology and Taxonomy of Species of Phomopsis on Asparagus

Morphology and Taxonomy of Species of <i>Phomopsis</i> on <i>Asparagus</i>

Morphology and Taxonomy of Species of Phomopsis on Asparagus

Phomopsis javanica, a new species on Asparagus from Java, is described and illustrated. It differs from P. asparagi by producing paraphyses among the conidiophores and conidiogenous cells, and is the first Phomopsis described with these structures. Phomopsis javanica was more virulent than P. asparagi when inoculated on asparagus foliage and stems. Phomopsis asparagicola is considered a synonym of P. asparagi. P. asparagi and P. javanica are compared in a series of photographs.

Acrocalymma medicaginis and Phomopsis sp. as Causal Agents of Crown Rot of Lucerne in Australia

AbstractFungi associated with crown rotting were isolated from 3 year‐old lucerne plants growing in sandy and loam soils in an irrigated stand, declining in productivity, at Langhorne Creek, South Australia. The method of isolation markedly affected the range of species recovered. Fusarium spp. and Phomopsis sp. were isolated from washed and surface sterilized crowns, whereas a larger range of fungi, especially Acrocalymma medicaginis, was isolated from unwashed crowns. A. medicaginis was most frequently isolated from rotted tissue flecked with red, while a species of Phomopsis was the dominant fungus in whitish tissue containing zone lines, especially in crown branches. A. medicaginis and Phomopsis sp. caused crown rotting of mature, wounded lucerne plants at temperatures equivalent to summer conditions at Langhorne Creek. There was no evidence that Fusarium oxysporum or F. solani, two of the most frequently isolated species, were pathogens of mature lucerne plants.

Zone lines diagnostic of Phomopsis sp. in lucerne crown rot.

A species of Phomopsis causing the formation of zone lines in rotting lucerne crowns is briefly described. Zone line formation in inoculated sterile lucerne blocks was favoured by slow drying of the blocks. Phomopsis sp. inoculated onto lucerne blocks in combination with other fungi isolated from rotting lucerne crowns resulted in zones of inhibition between some of the paired combinations. However, there was no evidence to suggest that zone lines were formed by Phomopsis sp. as a result of antagonism between it and other fungi.

A new species of Phomopsis recovered from field bindweed (Convolvulus arvensis)

Isolates of a Phomopsis recovered from diseased foliage of Convolvulus arvensis L. were morphologically distinct from other species of Phomopsis. Alpha-conidia were oblong to fusiform-ellipsoid, usually blunt at both ends with two guttules, and were distinctly larger than alpha-conidia of previously reported species. Beta-conidia were found only in culture. Stromata developed as small, superficial masses of aggregated mycelium, later becoming pulvinate, and were dark brown to black. Stromata were scattered throughout the colony, rarely aggregated. Pycnidia were uniostiolate or multiostiolate, usually arising from the stromata bodies, and pycnidial beaks were prominent. Leaf spot and anthracnose symptoms were reproduced on inoculated bindweed plants. The binomial Phomopsis convolvulus is proposed for this taxon.

Two new species of Phomopsis from India

Phomopsis micheliae sp.nov. and P. gmelinae sp.nov. are described from Kerala, India. P. micheliae causes a leaf spot disease of Michelia champaca and P. gmelinae a stem canker of Gmelina arborea.

Comparisons of Phomopsis isolates obtained from sunflower plants and debris in Yugoslavia

Six hundred collections of Diaporthe perithecia found on sunflower detritus during a 4-year study yielded Phomopsis helianthi. Two thousand other collections from sunflower plants were also recognized as P. helianthi. Four collections differed from this species in growth rate, colony characteristics, ability to grow at higher temperatures, tolerance to the antagonistic influence of other micro-organisms, ability to produce predominantly or only α-conidia, and failure to form perithecia. Although other Phomopsis species are found on sunflower in Yugoslavia, it is considered that severe outbreaks of the Phomopsis disease of this plant are currently caused only by P. helianthi.

A New Phomopsis Species from Soybean

A New Phomopsis Species from Soybean

A New Phomopsis Species from Soybean

A new species of Phomopsis isolated from soybean is described. The species, P. longicolla, differs from P. sojae, the anamorph of Diaporthe phaseolorum var. sojae, in several morphological characte...

Soybean seed deterioration in the tropics. I. The role of physiological factors and fungal pathogens

Two field experiments were conducted to determine whether the rapid loss of soybean seed viability in the lowland humid tropics is primarily due to physiological factors or to seed-borne microorganisms, or to both. In both experiments benomyl fungicide was applied (1 g/l) to four cultivars of contrasting storability as a foliar spray weekly from mid-flowering to maturity. The seeds were harvested at maturity or after a delay of two weeks. Plants in Experiment 1 matured under dry conditions and low fungi incidence. Harvest delay and benomyl treatment had little effect on seed pathogen incidence or germination at harvest. In Experiment 2, Which matured in moist conditions, delayed harvest reduced viability by 25%, with significant cultivar × harvest time interactions. Seeds from plants treated with benomyl had higher viability than seed from untreated plants, and significantly lower incidence of Phomopsis species, Macrophomina phaseoli, Fusarium species and Colletotrichum truncatum. Pathogens seem to be important in seed deterioration prior to harvest. To determine the effect of benomyl treatment on rate of decline in seed viability in storage, seeds from Experiment 1 and 2 were stored at 80% relative humidity and 28 or 35°C and sampled periodically. Seeds from benomyl-treated and untreated plants declined in viability at equal rates. Dusting of benomyl on seed of Bossier soybean equilibrated to 10, 13 or 16% moisture content before the start of storage at 28°C completely inhibited surface fungal growth, but did not influence rate of viability decline. Rate of viability decline varied directly with seed moisture content. Extracted embryos from freshly harvested Bossier seed grew on agar and were free from fungal pathogens, while embryos from seed stored for 9 months failed to grow even though little infection (0–5%) was observed. These results strongly suggest that the role of pathogens in seed deterioration during storage may frequently be secondary to that played by physiological factors.

Microbial populations associated with buds and young leaves of apple

Apple buds and developing leaves and floral parts were assessed for microbial populations by a washing procedure and scanning electron microscopy (SEM) at six stages ranging from dormancy through early tight cluster. Densities of yeasts, filamentous fungi, and bacteria associated with dormant buds were on an order of magnitude of 5 × 105 propagules per gram fresh weight of tissue. Populations tended to peak as buds swelled and to diminish during subsequent developmental stages. External surfaces of buds were colonized extensively. Internal surfaces, particularly those of the peripheral scales, also supported abundant microflora. Evidence from SEM suggested that few microorganisms were associated with floral and leaf primordia. Surface sterilization was not found to be an adequate method to discriminate between external and internal bud microflora. A partial list of microorganisms included fluorescent pseudomonads, Aureobasidium pullulans, and species of Cryptococcus, Sporobolomyces, Rhodotorula, Coniothyrium, Alternaria, Phomopsis, Phoma, Epicoccum, Cladosporium, Acremonium, Fusarium, Stachybotrys, and Sclerotium. These data are pertinent to the microbial ecology of the gemmisphere and to the prospective biological control of foliar pathogens.

A New Species of Phomopsis from India

Summary A new species of Phomopsis (Fungi imperfecti, Sphaeropsidales), P. jaunpurensis S RIVASAVA from the phylloclades of Muehlenbeckia platyclada M EISSN . has been described.

Phomopsis Destructum on Psidium Guajava Fruits in India

A serious fruit rot disease of Psidium guajava L. was noticed in the gardens of the University campus and in local orchards. The disease is prevalent and on an average about 60% of the fruits of a plant were found to be affected. The disease first appeared in December and rapidly spread during February and March. The infected fruits showed disease symptoms near the stalk. Under favorable environmental conditions, infection centers are numerous. Lesions are dark brown, at first small and increase in size to 2 cm diam (FIG. 1). The tissues soften and the entire fruit rots within 8-12 da. The rotted fruits fall from the parent plants causing a heavy loss in the yield of the crop. The causal fungus was isolated from diseased fruits of guava. This fungus grew and sporulated on potato dextrose agar. With the help of Dr. Punithalingam of Commonwealth Mycological Institute, Kew, England the fungus was identified as species of Phomopsis. At present, species of Phomopsis are identified on the basis of the host. According to the available literature no species of Phomopsis has been described from Psidium; thus the present isolate is described as new. The specific epithet refers to the annihilating nature of the fungus. Some healthy fruits of Psidium guajava were inoculated with the fungus by inoculum disc after pricking the fruit surface and also by spraying with a suspension of spores in sterile water. Seven da after inoculation, fruits incubated at 30 C showed brown spots. Symptoms of rotting also appeared after 4 da. From the inoculated fruit the same fungus was re-isolated. 1963. A redisposition o some fungi ascribed to the Hyaloscyphaceae. 1132

Toxicity and plant growth regulator effects of cytochalasin H isolated from Phomopsis sp.

A biologically active metabolite was found in crude extracts of an unidentified species of Phomopsis isolated from weevil-damaged pecans. Purified metabolite was toxic to day-old cockerels, with an LD50 of 12.5 mg/kg, and was markedly inhibitory to growth the floral development of tobacco plants at concentrations of 10(-2) to 10(-4) M. IR and 1H-nmr spectra indicated an alkylpheny moiety with a single nitrogen atom present as a secondary amide; and acetate ester, OH, CH3, and a trans-double bond function. Elemental and high-resolution mass-spectral analysis indicated a formula of C30H39NO5 and a molecular weight of 493.2886. The metabolite was identified as cytochalasin H.