Penicillium Hirsutum Research Articles

The Number and Species Diversity of Cultured Microfungi on the Barents Sea Coast

The number and diversity of cultivated microscopic fungi isolated from seawater, littoral and supralittoral soil on the coast of the Barents Sea were studied. Communities of microfungi are mainly represented by facultative marine fungi of terrigenous origin. The isolates mainly belonged to anamorphic fungi of the department Ascomycota and are represented by the genera Penicillium, Aspergillus, Talaromyces, Trichoderma, Acremonium etc., characteristic of the cold northern seas. The frequently found species in the study area were Aspergillus brasiliensis, Penicillium hirsutum, P. glabrum, P. spinulosum, P. janczewskii, Trichoderma koningii, T. viride, Talaromyces purpureogenus. The number of fungi in the supralittoral soil is two to three orders of magnitude higher than in the soils of the littoral zone and averaged from 4 to 13 thousand CFU/g. In sea water, the number of fungi was only a few units per ml. The maximum number of saccharolytic fungi was noted in the soils of the supralittoral zone. In the soils of the littoral and sea water, the number of hydrocarbon-oxidizing fungi varied from 52.5 to 143.3 CFU/g and from 0 to 4 CFU/ml, respectively. The number of saccharolytics varied from 0 to 113 CFU/g in the littoral soil and from 0 to 3 CFU/mL in sea water in all the studied areas, except for the most polluted ones, where it reached values of 200 CFU/g. An increase in the proportion of saccharolytic fungi in sea water and littoral may indicate anthropogenic pollution of the area, including hydrocarbons and other organic compounds. The urbanized areas of the Kola Bay with a high anthropogenic load were characterized by a richer species diversity and an increase in the proportion of pathogenic and opportunistic forms of microscopic fungi. A high level of hydrocarbon pollution negatively affected the number of saccharolytic fungi, while lower values of hydrocarbon content did not affect the number of saccharolytics. The number of fungi grown on Czapek’s mineral medium decreased as the amount of hydrocarbons both in sea water and in the littoral zone increased, which may indicate a high vulnerability of marine microfungi to pollution.

Design of Green Silver Nanoparticles Based on Primula Officinalis Extract for Textile Preservation.

The present study aims to bring an addition to biomass resources valorization for environmental-friendly synthesis of nanoparticles. Thus, the green synthesis of silver nanoparticles (AgNPs) was performed, using a novel and effective reducing agent, Primula officinalis extract. The synthesis was optimized by monitoring the characteristic absorption bands, using UV−Vis spectroscopy, and by evaluating the size and physical stability. The phenolic consumption was established using Folin-Ciocâlteu method (1.40 ± 0.42 mg, representing ~5% from the total amount of poly--phenols) and the antioxidant activity was evaluated using chemiluminescence and TEAC methods. The optimum ratio extract to Ag ions was 1:3, for which the AgNPs presented a zeta potential value of −29.3 ± 1.2 mV and particles size of 5−30 nm. For characterization, EDS and XRD techniques were used, along with microscopy techniques (TEM). The AgNPs dispersions were applied on natural textile samples (cotton and wool), as a novel antimicrobial treatment for textile preservation. The treated fabrics were further characterized in terms of chromatic parameters and antimicrobial effect against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Penicillium hirsutum strains. The high percentages of bacterial reduction, >99%, revealed that the AgNPs produced are a good candidate for textiles preservation against microbial degradation.

In Vitro and In Vivo Evaluation of Silver Nanoparticles Phytosynthesized Using Raphanus sativus L. Waste Extracts.

The aim of the current paper is the development of phytosynthesized silver nanoparticles mediated by Raphanus sativus L. extracts obtained through two extraction methods (temperature and microwave) and to test their potential application for controlling apple crops pathogens. The phytosynthesized materials were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. All the materials were evaluated in terms of antioxidant and in vitro antimicrobial activity (against bacteria, molds, and yeast: Escherichia coli ATCC 8738, Staphylococcus aureus ATTC 25923, Pseudomonas aeruginosa ATCC 9027, Salmonella typhimurium ATCC 14028, Candida albicans ATCC 10231, Venturia inaequalis, Podosphaera leucotricha, Fusarium oxysporum ATCC 48112, Penicillium hirsutum ATCC 52323, and Aspergillus niger ATCC 15475). Considering the results obtained in the in vitro assays, formulations based on nanoparticles phytosynthesized using Raphanus sativus L. waste extracts (RS1N) were evaluated as potential antifungal agents for horticultural crops protection, against Venturia inaequalis and Podosphaera leucotricha through in vivo assays. For the DPPH assay, the inhibition (%) varied between 37.06% (for RS1N at 0.8 mg/mL concentration) and 83.72% (for RS1N at 7.2 mg/mL concentration) compared to 19.97% (for RS2N at 0.8 mg/mL) and only 28.91% (for RS2N at 7.2 mg/mL). Similar results were obtained for RS3N (85.42% inhibition at 7.2 mg/mL) compared with RS4N (21.76% inhibition at 7.2 mg/mL). Regarding the ABTS assay, the highest scavenger activity values were recorded for samples RS1N (91.43% at 1.6 mg/mL) and RS3N (96.62% at 1.6 mg/mL).

Genoprotective, antioxidant, antifungal and anti-inflammatory evaluation of hydroalcoholic extract of wild-growing Juniperus communis L. (Cupressaceae) native to Romanian southern sub-Carpathian hills

BackgroundJuniperus communis L. represents a multi-purpose crop used in the pharmaceutical, food, and cosmetic industry. Several studies present the possible medicinal properties of different Juniperus taxa native to specific geographical area. The present study aims to evaluate the genoprotective, antioxidant, antifungal and anti-inflammatory potential of hydroalcoholic extract of wild-growing Juniperus communis L. (Cupressaceae) native to Romanian southern sub-Carpathian hills.MethodsThe prepared hydroethanolic extract of Juniperus communis L. was characterized by GC-MS, HPLC, UV-Vis spectrometry and phytochemical assays. The antioxidant potential was evaluated using the DPPH assay, the antifungal effect was studied on Aspergillus niger ATCC 15475 and Penicillium hirsutum ATCC 52323, while the genoprotective effect was evaluated using the Allium cepa assay. The anti-inflammatory effect was evaluated in two inflammation experimental models (dextran and kaolin) by plethysmometry. Male Wistar rats were treated by gavage with distilled water (negative control), the microemulsion (positive control), diclofenac sodium aqueous solution (reference) and microemulsions containing juniper extract (experimental group). The initial paw volume and the paw volumes at 1, 2, 3, 4, 5 and 24 h were measured.ResultsTotal terpenoids, phenolics and flavonoids were estimated to be 13.44 ± 0.14 mg linalool equivalent, 19.23 ± 1.32 mg gallic acid equivalent, and 5109.6 ± 21.47 mg rutin equivalent per 100 g of extract, respectively. GC-MS characterization of the juniper extract identified 57 volatile compounds in the sample, while the HPLC analysis revealed the presence of the selected compounds (α-pinene, chlorogenic acid, rutin, apigenin, quercitin). The antioxidant potential of the crude extract was found to be 81.63 ± 0.38% (measured by the DPPH method). The results of the antifungal activity assay (for Aspergillus niger and Penicillium hirsutum) were 21.6 mm, respectively 17.2 mm as inhibition zone. Test results demonstrated the genoprotective potential of J. communis undiluted extract, inhibiting the mitodepressive effect of ethanol. The anti-inflammatory action of the juniper extract, administered as microemulsion in acute-dextran model was increased when compared to kaolin subacute inflammation induced model.ConclusionThe hydroalcoholic extract obtained from wild-growing Juniperus communis native to Romanian southern sub-Carpathian hills has genoprotective, antioxidant, antifungal and anti-inflammatory properties.

Mitodepressive, antioxidant, antifungal and anti-inflammatory effects of wild-growing Romanian native Arctium lappa L. (Asteraceae) and Veronica persica Poiret (Plantaginaceae)

The present study aims to evaluate the potential uses of hydroalcoholic extracts obtained from Romanian native wild-growing plants. The hydroalcoholic extracts were obtained from the burdock roots and respectively the aerial parts of birdeye speedwell. The extracts were characterised by HPLC (quantifying 13 compounds in the V. persica extract, 6 compounds in the A. lappa extract and confirming the presence of arctiin and arctigenin in the burdock extract). The antioxidant potential of the crude extracts was evaluated using two methods: the DPPH assay (79.91% for speedwell extract, 76.23% for burdock extract) and the phosphomolybdate method (296.5 mg/g ascorbic acid equivalents for burdock, 324.4 mg/g for speedwell). The crude extracts were found to be active against both fungal lines used (Aspergillus niger and Penicillium hirsutum), inhibition zones - 17.1 mm and 13.1 mm against P. hirsutum, respectively ca. 22 mm for both extracts against A. niger. The cytogenetic effects (assessed using the Allium cepa assay) revealed a series of chromosomal aberrations and nuclear aberrations induced in the meristematic root cells. The anti-inflammatory effect, estimated in two inflammation experimental models, showed a significant effect, especially for the speedwell extract. The results recommend the evaluated extracts as promising sources of biologically-active compounds.

Chemical Composition, Herbicidal and Antifungal Activity of Satureja cuneifolia Essential Oils from Spain

The chemical composition of essential oils from Satureja cuneifolia growing in east Spain was analyzed by GC, GC/MS. Forty-five compounds accounting for 99.1% of the total oil were identified. Camphor (47.6%), followed by camphene (13.6%) were the main compounds. Their herbicidal and antifungal activity was tested in vitro against three weeds (Amaranthus hybridus, Portulaca oleracea and Conyza canadensis) and eleven common pathogenic or saprophytic fungi (Phytophthora citrophthora, P. palmivora, Pythium litorale, Verticillium dahlia, Rhizoctonia solani, Penicillium hirsutum, Colletotrichum gloeosporioides, Phaeoacremonium aleophilum, Phaemoniella chlamydospora, Cylindrocarpon liriodendri and C. macrodidymum). The essential oil was very active against A. hybridus and C. canadensis significantly inhibiting their germination and seedling growth. Minor activity was shown against P. oleracea, depending on the concentration applied. P. palmivora, P. citrophthora and Pa. chlamydospora were the most sensitive fungi to the treatment with the essential oil, whereas R. solani showed no inhibition. Results showed that S. cuneifolia essential oil could be used for biocontrol of weeds and fungal plant diseases.

Innovative phytosynthesized silver nanoarchitectures with enhanced antifungal and antioxidant properties

While in the early era of nanotechnology, nanoparticles of noble metals were obtained through expensive methods, using toxic chemical reagents, in the last decade attempts are made to obtain the desired chemical composition, size, morphology, and other properties by eco and green synthesis, using plants. The aim of this paper is to compare two extraction methods (hydroalcoholic extraction and microwave extraction) used to phytosynthesize silver nanoparticles, in terms of nanoparticle (NP) morphology, antioxidant, and antifungal action, using an European native plant, Anthriscus cerefolium (L.) Hoffm. The extracts and the obtained NPs were characterized by modern analytical techniques (GC–MS, UV–Vis, SEM, TEM) and by phytochemical assays (total flavonoids, total terpenoids and total phenolic content). The antifungal activity (evaluated using the Kirby–Bauer method, against Aspergillus niger and Penicillium hirsutum) and the antioxidant activity (determined by the DPPH assay and a chemiluminescence assay) revealed notable differences between the samples, differences due to the extraction procedure followed. Also, preliminary studies regarding the stability and the toxicity of the nanoparticles are presented. By using the microwave-assisted extraction, not only smaller particles (less than 10nm) were obtained, but also with better antifungal and antioxidant properties than the ones obtained by classical extraction.

Host ranges of North American isolates of Penicillium causing blue mold of bulb crops

Single isolates of four Penicillium species belonging to series Corymbifera (Penicillium allii, Penicillium hirsutum, Penicillium tulipae, Penicillium venetum) plus an isolate of Penicillium polonicum, all from North American sources, were inoculated individually into Crocus sativus (crocus), Allium sativum (garlic), Allium cepa (onion), Allium stipitatum (ornamental onion), Iris hollandica (iris), Ornithogalum umbellatum (grass lily), and varieties of Gladiolus (gladiolus), Tulipa (tulip) and Narcissus (daffodil). All isolates were pathogenic to garlic and onion (but none to ornamental onion), and all but P. polonicum to Tulipa, although virulence varied considerably. Additionally, P. hirsutum was pathogenic to Crocus, Gladiolus and Iris; P. tulipae to Narcissus, Crocus, Ornithogalum and Iris; P. venetum to Gladiolus, Ornithogalum and Iris; and P. polonicum to Iris. Nomenclature and taxonomy of series Corymbifera are summarized, the above results compared to similar investigations in Europe, and management implications provided.

미산성 차아염소산수의 식물병원균류에 대한 살균 효과

미산성 차아염소산수는 다양한 종류의 미생물들에 대해 강력한 살균력을 나타내지만 인간과 자연에 무해한 살균제로 잘 알려져 있다. 4%의 희석된 염산만으로 무격막 전해조에서 전기분해를 통해 만들어졌으며 유효염소 농도가 20~30 ppm(HOCl 97%)이고 pH 5.0~6.5인 미산성 차아염소산수의 식물병원균들에 대한 살균효과를 조사하였다. Botrytis cinerea, Colletotrichum acutatum, Phytophthora capsici 등의 포자들에 대해서는 대략 10초 정도의 처리시간으로도 100% 살균효과가 나타났으나 Penicillium hirsutum의 경우는 3분 이상의 처리시간이 요구되었다. 희석농도에 따른 C. acutatum에 대한 살균효과를 조사한 결과 1:1(미산성 차아염소산수:멸균수)의 비율로 희석한 처리구에서는 포자발아가 100% 억제되었으나 1:2 처리구에서는 63%로 억제율이 낮아졌다. 고추탄저병균 C. acutatum을 고추열매에 접종한 후 24시간이 지나서 처리된 미산성 차아염소산수의 병방제 효과를 조사한 결과 방제가는 70.4%였다. 본 연구를 통해 미산성 차아염소산수의 강하고 광범위한 살균력이 확인되었으며 식물병 방제를 위한 살균제로 유용하게 활용될 수 있을 것으로 예상됐다. Slightly acidic hypochlorous water (SAHW) is well known for having a powerful and broad spectrum antimicrobial activity, and is harmless to the environment and humans. SAHW (pH 5~6.5, 20~30 ppm available chlorine concentration) was generated by electrolysis of dilute solution of HCl (4%) in a chamber of a non-membrane electrolytic cell. Our objective was to determine SAHW has a potential fungicidal activity on some phytopathogenic fungi. Spores of Botrytis cinerea, Colletotrichum acutatum and Phytophthora capsici were not culturable on agar media at approximately 10 seconds after treatment by SAHW. However, inactivation of Penicillium hirsutum was required over 3 min. Dilution of SAHW with sterilized distilled water (SDW) at the ratio of 1:1 (SAHW:SDW) against C. acutatum showed 100% inactivation but, the efficacy in 1:2 decreased until 63.2%. Control value of SAHW was 70.4% against C. acutatum on pepper fruits when applied upto 24 h postinoculation. SAHW has a powerful and wide spectrum antifungal activity and could be applied as a potential alternative to fungicidal agent for control of plant disease.

마늘 푸른곰팡이병 방제용 Pantoea agglomerans 59-4의 억제기작 해석

To screen for potential biocontrol agents against postharvest disease of garlics caused by Penicillium hirsutum, a total of 1292 isolates were isolated from the rhizoshere or rhizoplane of Allium species. Among them, S59-4 isolate was selected as a potential biocontrol agent by in vivo wounded garlic bulb assay. The isolate was identified as Pantoea agglomerans (Pa59-4) through Biolog system. Pa59-4 did not inhibit the mycelial growth of P. hirsutum in dual-culture with P. hirsutum on tryptic soy agar. In order to elucidate mode of action of Pa59-4 on biological control, nutrient competition between Pa59-4 and P. hirsutum was investigated by the simple method using tissue culture plates with cylinder inserts containing defusing membrane reported by Janisiewicz et al. (2000). The results showed that Pa59-4 effectively suppressed spore germination and mycelial growth of blue mold in the low concentration (0.5%) of garlic juice, but it did not suppress those of blue mold in the high concentration (5%) of garlic juice. This result suggests that the mechanism in biocontrol of garlic blue mold by Pa 59-4 may be involved in nutrient competition with P. hirsutum on garlic bulbs.

Pathogenic Fungi in Garlic Seed Cloves from the United States and China, and Efficacy of Fungicides Against Pathogens in Garlic Germplasm in Washington State

AbstractCommercially distributed garlic (Allium sativum) seed cloves from six states of the United States and mainland China were surveyed for the presence of fungi recorded as pathogenic to garlic in the literature.Aspergillus niger, A. ochraceus, Botrytis porri, Embellisia allii, Fusarium oxysporumf. sp.cepae, F. proliferatumandPenicillium hirsutum, were each recovered from one or more of these commercial sources, as wasF. verticillioides, not previously reported as pathogenic to garlic, but here demonstrated to be a pathogen. Seed garlic distributed from public germplasm collections may also contain fungal pathogens:E. allii, F. oxysporumf. sp.cepaeand/orF. proliferatumcaused severe losses in 2002–2003 and 2005–2006 during germplasm regeneration and storage for the National Plant Germplasm System in Pullman, Washington. Use of fludioxonil, thiophanate methyl and/or benomyl (the latter withdrawn from the market, but used here as a standard) at label rates againstE. alliiandFusariumspecies promoted plant health, but not when infections were located deep within tissues nor under some situations involving high disease pressure.

First report of Penicillium allii as a field pathogen of garlic (Allium sativum)

Blue mould disease in garlic (Allium sativum) is associated worldwide with various Penicillium species, and has been attributed to significant annual crop losses in Argentina; the world's second largest exporter of garlic. To identify the pathogenic Penicillium species responsible, affected plants were sampled in La Consulta station (33°45′ S, 69°02′ W) and placed in a damp chamber. Characteristic disease symptoms are stunted and chlorotic plants with withered leaves and reduced bulb size. Bulbs are often covered with blue/green conidial masses. Isolations were made from fungal colonies emerging on affected bulbs. Pure cultures (IBT 26466, 26467, 26511 and 26512; CMB collection, BioCentrum-DTU, Denmark) were initially identified by micromorphology as Penicillium allii, and identifications were confirmed by comparing reversed phase-HPLC secondary metabolite profiles with those of P. allii type strains. To confirm pathogenicity, sterilized garlic cloves were injured with a needle and inoculated with 5 µL P. allii spore suspensions (adjusted to 5 × 106 conidia mL−1). Inoculated cloves were planted in a field not previously cultivated with garlic, and the original disease symptoms were produced on inoculated plants while water-inoculated control plants remained healthy. The survival rate of inoculated plants was 68% and P. allii was reisolated from diseased field plants. Penicillium viridicatum was first reported as the causal agent of blue mould of garlic in Argentina (Gatica & Oriolani, 1984) before the characterization of P. allii (Vincent & Pitt, 1989). Penicillium allii is micromorphologically similar to P. viridicatum and both species produce yellow exudates in pure culture. To compare pathogenic ability, standard P. viridicatum strains IBT 16939 and 15053 were inoculated into sterilized garlic cloves and incubated for 12 days. The P. viridicatum strains were not able to sporulate on the garlic cloves. Penicillium hirsutum was recently reported as a pathogen on garlic in Argentina (Cavagnaro et al., 2005). However, P. allii but not P. hirsutum has been reported as an aggressive pathogen of garlic in comparative pathogenicity trials conducted in damp chambers (Overy et al., 2005). The results reported here suggest that P. allii, rather than P. hirsutum or P. viridicatum, is the pathogenic species responsible for garlic crop losses due to blue mould rot in Argentina. This is the first report confirming P. allii as a field pathogen of A. sativum. This work was partly supported by project Pict # 0803687 of Argentina.

Host-derived media used as a predictor for low abundant, in planta metabolite production from necrotrophic fungi

Penicillium ser. Corymbifera strains were assayed on a variety of media and from infected Allium cepa tissues to evaluate the stimulation and in planta prediction of low abundance metabolites. Stimulated production of corymbiferones and the corymbiferan lactones were observed for Penicillium albocoremium, Penicillium allii, Penicillium hirsutum, Penicillium hordei and Penicillium venetum strains cultured on tissue media. Target metabolites were sporadically detected from strains cultured on common laboratory media (CYA, MEA and YES). Up to a 376 times increase in corymbiferone and corymbiferan lactone production was observed when culture extracts from CYA and A. cepa agar were compared by high pressure liquid chromatography with ultraviolet and mass spectrometry (LC-UV-MS). The novel metabolite corymbiferone B was purified and structure elucidated from a P. allii/A. cepa tissue medium extract. In planta expression of low abundance, target metabolites were confirmed from infected A. cepa tissue extracts by LC-UV-MS. Secondary metabolite production was directly dependent and influenced by media conditions, resulting in the stimulated production of low abundance metabolites on host-derived media. The use of macerated host tissue media can be applied in vitro to predict in planta expression of low abundance metabolites and aid in metabolite origin annotation during in planta metabolomic investigations at the host/pathogen interface.

Resistance to Penicillium hirsutum Dierckx in garlic accessions

Among the factors affecting the quality and yield of garlic production, blue mold caused by -- Penicillium spp. -- is responsible for economical losses in many countries. Allicin, present in garlic bulbs, has been suggested as having antifungal activity against some Penicillium species. This study was conducted to evaluate the response of garlic accessions against Penicillium hirsutum infection and to compare this response with bulb allicin content. Twelve garlic accessions were inoculated with P. hirsutum, and assayed in greenhouse and growth chamber experiments. Plant growth parameters and the fungal production of conidia were evaluated. Significant differences were found among the accessions. Accessions Castano and Morado were most resistant whereas AR-I-125 and Fuego were always severely affected by the disease. A low correlation was found (r = 0.17) between allicin content and tolerance, indicating that allicin is not the main factor involved in the resistance against P. hirsutum.

Isolation of Penicillium hirsutum from spoiled, packaged asparagus spears in Japan

During storage studies on asparagus spears packed in plastic film and held at 15°C, a Penicillium fungus was associated with subsequent spoilage. On the basis of colony characteristics, the isolate was identified as Penicillium hirsutum Diercks. This report is the first of Penicillium hirsutum causing spoilage of asparagus spears in Japan. Inoculation tests showed that among all the Penicillium species tested in this study only the identified fungus was able to infect asparagus spears.

Fungi from Chernobyl: mycobiota of the inner regions of the containment structures of the damaged nuclear reactor

Extensive fungal growth has been detected on the walls and other building constructions in the inner parts of the Shelter of the damaged fourth Unit of the Chernobyl Nuclear Power Plant in 1997-98. The mycobiota comprised 37 species of 19 genera. Zygomycetes and ascomycetes were represented by one species each: Mucor plumbeus and Chaetomium globosum, respectively. Two mitosporic fungi commonly found were Cladosporium sphaerospermum and Penicillium hirsutum. Alternaria alternata, Aureobasidium pullulans, Aspergillus versicolor, Acremonium strictum, and Cladosporium herbarum were also encountered. Penicillium ingelheimense, Phialophora melinii, Doratomyces stemonitis and Sydowia polyspora were isolated from the Shelter and are recorded from the Ukraine for the first time. Comparison of the species growing under both severe and relatively weak radioactive contamination revealed a dominance of melanin-containing species in heavily contaminated sites; biodiversity and prevalence coefficients supported this.

Fungal succession on leaves of Alchornea triplinervia (Spreng.) Muell. Arg. submerged in a stream of an Atlantic Rainforest in the state of São Paulo, Brazil

Leaves of Alchornea triplinervia (Spreng.) Muell. Arg. were submerged in a stream in an Atlantic Rainforest in Sao Paulo state, Brazil, from July/1988 to June/1989 and from July/1989 to May/1990. Fungi were isolated by the leaf disks washing technique followed by plating on culture media and also by using baiting techniques (using substrates with chitin, keratin and cellulose), what resulted on 565 fungal registers corresponding to 81 taxa. The most common species found during this study of the fungal succession were Trichoderma viride Pers. ex S.F. Gray and Fusarium oxysporum Schlecht emend. Snyd. & Hans. (23 registers), Penicillium hirsutum Dierckx (21 registers), Fusarium solani (Mart.) Appel & Wollenw. emend. Snyd. & Hans. (17), followed by 14 registers of: Cylindrocladium scoparium Morgan, Triscelophorus monosporus Ingold and Polychytrium aggregatum Ajello. Although the monthly obtained mycota had been composed by species of different taxonomic groups, the fungal succession was defined by the initial presence of typical terrestrial leaf inhabiting fungi (mostly Deuteromycotina), followed by species of Mastigomycotina and Zygomycotina. Combining culture methods and baiting techniques, it was possible to verify the presence of terrestrial fungi on the decomposition of submerged leaves and the importance of zoosporic fungi in the fungal succession. This is the first paper about the fungal succession on the decomposition of leaves submerged in a lotic ecosystem in Brazil.

Fungi associated with, and possible causes of, neck rot of narcissus

SummaryNeck rot symptoms in post-harvest narcissus bulbs in the UK in the 1970s and 1990s were associated with Fusarium oxysporum, Botrytis narcissicola and Penicillium hirsutum. Their frequencies and the incidence of neck rot were similar in the studies in the two decades. On their own F. oxysporum, P. hirsutum and B. narcissicola were isolated from neck rots from only one, no and no stocks in the 1970s and from four, one and no stocks in the 1990s respectively. In most of the stocks, neck rot was associated with more than one of the three fungi. The most frequent combination in the 1970s was all three fungi and in the 1990s P. hirsutum with B. narcissicola. In the 1990s, F. oxysporum was found in 51% of stocks, being detected in rots extending to the bulb base and being responsible for the lack of shoot emergence. B narcissicola and P. hirsutum were found in 76% and 92% of stocks, respectively, and were isolated from rots of the neck, rots extending to the middle of the bulb and from completely rotted bulbs. A survey of crop husbandry practices in the 1990s revealed that only the presence of F. oxysporum was related to a stock problem. B. narcissicola was isolated in fewer bulbs from crops following cereals, crops treated with foliar sprays of dicarboximide fungicides and pre-store dip treatments of MBC (benzimidazole) or formaldehyde. There were fewer bulbs with P. hirsutum where bulbs had been planted at depths of 15 cm or less, following dicarboximide and MBC foliar treatments but more bulbs had P. hirsutum following bruising. These studies have shown that F. oxysporum is not the sole cause of narcissus neck rot; B. narcissicola and P. hirsutum are involved and these warrant further investigation.

Changes in conidial morphology and germinability of Botrytis allii and Penicillium hirsutum in response to low-temperature incubation

Botrytis allii and Penicillium hirsutum spores, produced at 20, 10, 4, 0 and − 2 °C on potato dextrose agar, showed a clearly inverse relationship between spore volume and incubation temperature. The spore volumes of both B. allii and P.hirsutum were greatest at − 2° and smallest at 20°. The mean volume of B. allii conidia produced at − 2° was 2·8 times larger than that of conidia produced at 20°, whereas the volume of P. hirsutum doubled. When the spores produced at different temperatures were incubated at 20, 10, 4, 0, −2 and −4°, the large conidia from the lower temperature conditions germinated much earlier and had a faster germ-tube growth than the small ones, particularly when the temperature for spore germination was below 0°.

Low-temperature biology and pathogenicity of Penicillium hirsutum on garlic in storage

Penicillium hirsutum grown on potato dextrose agar and kept at 20, 10, 4, 2, 0, −2 and −4 °C for 25 weeks revealed a longer lag phase at 0 °C and below, and its growth was reduced as the temperature was lowered. At −4 °C, the fungus showed slight lengthening of the hyphae only after 19 weeks. Sporulation and germination of conidia were also delayed by low temperatures, and at −4 °C there was no production or germination. All of the wounded and inoculated cloves of ‘Bianco Piacentino’ garlic showed symptoms of blue mould disease after four weeks of storage at temperatures between 0 and 20 °C. At −2 °C, P. hirsutum colonised all of the cloves after seven weeks, while at −4 °C they were all still healthy after 16 weeks. No freezing injury was encountered at negative temperatures. A storage temperature of −4 °C is advisable for the prevention of blue mould disease.