A comparison of the effect of three fungicides on growth and roridin E production by Myrothecium roridum

Three fungicides, chlorothalonil, dichloran and mancozeb were studied to determine the effects on growth and production of roridin E by Myrothecium roridum in vitro. With increasing concentrations of fungicides, both growth and production of roridin E were inhibited. Of the three fungicides, chlorothalonil was much more effective in the inhibition of growth and production of roridin E, than dichloran and mancozeb.     

Effects of fungicides on the growth and conidial germination of Colletotrichum coccodes and on the development of black dot disease of potatoes

The effects of 10 fungicides on the growth of Colletotrichum coccodes in agar culture and on the germination of conidia was investigated. In field experiments in 1990 and 1991 the extent to which treating black dot-affected potato seed tubers with fungicides affected the development of the disease on stem bases, roots and tubers was assessed. Black dot was also assessed on plants from field trials in 1990 which were designed to investigate the efficacy of the soil sterilant 1,3-dichloropropene (Telone) and two nematicides, aldicarb (Temik) and ethoprophos (Mocap). Prochloraz and fenpiclonil were the most effective fungicides in decreasing the size of C. coccodes colonies on agar. Imazalil, propiconazole and dichlorophen were also effective, but at higher concentrations, whereas tolclofos-methyl, thiabendazole and benomyl were only moderately effective. Resistant sectors developed from inhibited colonies on agar containing fenpiclonil and tolclofos-methyl. Conidial germination was prevented at 1 mg/litre fenpiclonil and 5 mg/ litre dichlorophen; imazalil, benomyl and thiabendazole were also moderately effective. Fenpiclonil and propiconazole seed tuber treatments consistently decreased black dot infection on roots, stem bases and daughter tubers early in the season, but only fenpiclonil decreased disease on tubers at harvest in October. Propiconazole also delayed emergence and decreased stem numbers. Soil treatment with 1,3-dichloropropene, aldicarb or ethoprophos had no effect on black dot but Rhizoctonia solani tuber infection and black scurf were increased.     

Effect of surfactants and fungicides on clubroot (Plasmodiophora brassicae) of brassicas

Two formulations of the surfactant sodium dioctyl sulphosuccinate (Aerosol OT, Monawet MO70), one of alkyl phenyl ethylene oxide (Agral) and three fungicides (PP192, dichlorophen and a thiabendazole/iodophor complex -Byatran) were tested in field trials for control of clubroot (Plasmodiophora brassicae) on cabbage in 1988 and 1989. A standard mercurous chloride treatment (pre-sowing compost incorporation) was included in all experiments. Plants were raised in 64 cm³ blocks (1988) or 15 cm³ free-fill cells (1989). Mercurous chloride reduced disease severity and increased yield in both years. Byatran was ineffective. The surfactants and dichlorophen, applied as pre-planting soaks to the plant-raising compost, restricted disease development and increased yield in 1988 but not in 1989. A similar treatment with PP192 restricted disease severity and enhanced yield in both years. Pouring the surfactants and dichlorophen into the planting hole was more effective than using them to soak the compost. In 1989 pour treatments with Agral and a combined soak/pour treatment with dichlorophen reduced disease severity and increased yields by 250% and 97% respectively; compost treatment with PP192 gave a 150% increase.     

The interaction between mushroom strains and fungicides in the control of dry bubble disease caused by Verticilliumfungicola

Five fungicides were compared for control of Verticilliumfungicola on six strains of the cultivated mushroom. The strains showed considerable differences both in their sensitivity to the fungicides and their susceptibility to infection. These factors complicated comparison of the fungicides, but benodanil was less effective than chlorothalonil against V. fungicola.     

工厂化生产海鲜菇菌包污染霉菌的鉴定及防治

对工厂化生产中海鲜菇菌包污染霉菌进行分离,根据霉菌的形态特征、培养性状及ITS序列分析,鉴定其为哈茨木霉、拟康氏木霉、脉孢霉、长枝木霉、黑曲霉、产红青霉和产黄青霉;在此基础上探讨了常用抑菌剂对霉菌的防治效果及对海鲜菇菌丝生长的影响。结果表明,质量浓度100 mg/L克霉灵对哈茨木霉、黑曲霉、产红青霉、产黄青霉、拟康氏木霉有强抑制作用,质量浓度100 mg/L多菌灵对长枝木霉、产红青霉、产黄青霉、拟康氏木霉有强抑制作用,二者对海鲜菇菌丝生长的抑制都比较弱。可为海鲜菇工厂化生产中污染霉菌的综合防治提供参考。     

Contribution of Pathogens to Peach Fruit Rot in Northern Greece and their Sensitivity to Iprodione, Carbendazim, Thiophanate-methyl and Tebuconazole Fungicides

This study identified the main pathogens causing fruit rots of mature peaches in northern Greece, the major peach producing area of Greece. The brown rot pathogen Monilinia laxa was responsible for approximately 70% and 78% of rotted peaches in 2005 and 2006 respectively. Serious damage (up to 5%) was also caused with the fungus Phomopsis amygdali. Other pathogens isolated from rotted peaches at a low percentage were Alternaria alternata, Aspergillus niger, Aspergillus flavus, Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium spp., Colletotrichum gloeosporioides, Rhizopus stolonifer and Gilbertella persicaria. Most fungal isolates originated from the rotted peaches were tested for their sensitivity to the fungicides iprodione, carbendazim, thiophanate methyl and tebuconazole at label recommended concentrations. All fungicides inhibited the growth of M. laxa, A. niger, A. flavus, S. sclerotiorum, P. amygdali and B. cinerea on poisoned agar. Apart from iprodione, all other fungicides inhibited the mycelium growth of the pathogen Fusarium sp. The mycelium growth of Fusarium sp. was significantly less with iprodione than control. Only iprodione and tebuconazole were effective against A. alternata and R. stolonifer. Tebuconazole inhibited the mycelium growth of R. stolonifer, while iprodione reduced significantly in comparison to control. The mycelium growth of the fungus C. gloeosporioides was inhibited by tebuconazole and reduced significantly by the fungicides thiophanate methyl, carbendazim and iprodione. Among all the fungi tested, only M. laxa and B. cinerea isolates were found resistant to benzimidazoles [the EC50 (50% effective concentration) value was 100–200 mg/l and 200–300 mg/l for the largest number of thiophanate methyl‐ and carbendazim‐resistant M. laxa isolates respectively, while the biggest number of B. cinerea thiophanate methyl‐ and carbendazim‐resistant isolates showed EC50 value 200–300 mg/l and 300–400 mg/l, respectively]. However, these strains were sensitive to tebuconazole and iprodione. Therefore, these fungicides can be used as an alternative method to control benzimidazole‐resistant Monilinia and Botrytis isolates.     

Influence of commercial fungicides on the germination,growth and virulence of four species of entomopathogenic fungi

The influence of 15 commercially available fungicides on the germination, growth and virulence of Metarhizium anisopliae, Beauveria bassiana, Isaria fumosorosea, and Lecanillium longisporum was evaluated. The influence of the fungicides on conidial germination was dependant on the fungicide type and dose. Most fungicides retarded conidial germination of all the fungi tested at 10× and at the recommended rate of application, however, their toxicity declined at lower concentrations. Most of the fungicides inhibited mycelial growth of B. bassiana, whereas L. longisporum growth was unaffected. Only two and eight fungicides influenced mycelial growth of I. fumosorosea and M. anisopliae, respectively. None of the fungicides influenced the virulence of B. bassiana and L. longisporum, however, tolylfluanid and azoxystrobin reduced the virulence of M. anisopliae and I. fumosorosea, respectively. These studies clearly show that certain fungicides have the potential to inhibit germination of entomopathogenic fungi in vitro but appear to have little or no effect on their virulence against target insects.     

Identification of a Vibrio strain producing antimicrobial agents in the excretory organs of Nautilus pompilius (Cephalopoda: Nautiloidea)

The aim of the present study was to identify and characterize bacteria producing antimicrobial compounds in the excretory organs of Nautilus pompilius. Culture-dependent and culture-independent complementary approaches were used for bacterial identification such as: culture on selective media, Gram staining, CARD-FISH, direct DNA extraction from host tissue, PCR amplification and sequencing of the bacterial 16S rRNA gene. Results show presence of three bacterial groups: γ-Proteobacteria with three clusters (Pseudomonadales, Vibrionales, Alteromonadales), β-Proteobacteria and spirochetes. In order to screen for active strains, antimicrobial activity was tested by diffusion agar assay against Micrococcus luteus, Escherichia coli, Vibrio harveyi, and Candida albicans. Nautilus isolates showed antimicrobial activities against both Gram-positive and Gram-negative reference strains. Most of the active strains were phylogenetically related to environmental Vibrionaceae. These strains were always abundant in N. pompilius PA but were absent from Nautilus macromphalus from other geographical areas. Therefore, we suggest that antimicrobial active Vibrionaceae infect N. pompilius by environmental transmission.     

Double resistance by citrus green mould Penicillium digitatum to the fungicides guazatine and benomyl

In vitro dosage response data with different isolates of Penicillium digitatum and the fungicide guazatine indicated an approximate 10-fold shift in tolerance when compared with wild type strains. ED₅₀ values for resistant strains were approximately 0.5 μg/ml compared to approximately 0.05, μg/ml for the wild type strains. Colony growth of guazatine resistant isolates on selective media containing carbendazim showed that they were also resistant to the benzimidazole group of fungicides. In vivo tests in inoculated oranges with strains previously characterised by in vitro tests confirmed resistance to guazatine and benomyl. A combined treatment of these fungicides at 400 /μ/ml and 500 μg/ml respectively, which normally gives protection against decay, also failed to provide adequate mould control. Growth and pathogenicity of the resistant strains in these tests in oranges were indistinguishable from that of wild type strains.     

Antifungal effects of volatile organic compounds from the endophytic fungus Cryptosporiopsis ericae Cc-HG-7 isolated from Coptis chinensis Franch

In this study, 136 strains of endophytic fungi were isolated from the Chinese traditional medicinal plant Coptis chinensis Franch. Of these, 129 strains were classified into 12 different genera according to morphological traits and internal transcribed spacer (ITS) gene sequence analyses. Their antifungal activities were assessed against the following fungi: Magnaporthe oryzae, Pythium graminicola, Cylindrocarpon destructans, Fusarium oxysporum, Cercospora zeae-maydis, Sclerotinia sclerotiorum, Setosphaeria turcica and Botrytis cinerea. Fourteen endophytic strains were active against at least one of the selected fungi. The most active strain Cc-HG-7 identified as Cryptosporiopsis ericae displayed inhibition rates of 81.42% and 72.00%, respectively, against S. sclerotiorum and S. turcica in dual culture technique. The volatile antifungal compounds were identified using headspace solid-phase microextraction, followed by gas chromatography mass spectrometry to investigate the potential biocontrol mechanisms of strain Cc-HG-7. The results suggested that the strain Cc-HG-7 could be a potential agent for the biological control of S. sclerotiorum and S. turcica.     

Fungicide resistance in cucurbit downy mildew – methodological, biological and population aspects

Cucurbit downy mildew, caused by Pseudoperonospora cubensis, is among the most devastating diseases of cucurbitaceous plants. In spite of improved cultural practices and breeding for resistant cultivars, chemical control is still a very important tool to manage the disease. During the last several decades, many fungicides from various chemical classes have been developed. The occurrence of strains of P. cubensis resistant/tolerant to some fungicides encouraged research of this phenomenon. The first part of this article summarises the many different methodological approaches such as field trials, in vitro testing on active plant tissues or molecular diagnoses developed for the detection of resistant/tolerant strains of P. cubensis, as well as methods to collect and maintain pathogen isolates. The second part outlines the commonly used fungicides to control P. cubensis and their features like systemicity, biological and biochemical mode of action and translocation behaviour within plants. The last part deals with geographical aspects such as first appearance of resistance problems, distribution of resistance, temporal development of resistance under selection pressure by a fungicide, fitness of resistant subpopulations in competition with sensitive ones in the absence of a fungicide, as well as genetic and molecular sources of resistance.     

Biotoxic effects of Sumisclex and Carbomar fungicides on four Aspergillus species isolated from the rhizosphere of some Taif plants

Abstract

The antifungal activities of two systemic fungicides (Sumisclex and Carbomar) on four rhizospheric Aspergillus species (A. candidus, A. sydawi, A. niger1 and A. niger2) were studied. Also the phytotoxicity against some saudian seeds was analysed. Results indicated that Sumisclex fungicide was more effective on the growth of A. candidus and A. sydawi under laboratory conditions (the IC₅₀ of 3 and 4 ppm were recorded, respectively) than Carbomar where an IC₅₀ of 11 ppm for A. candidus and 35 ppm for A. sydawi were observed. The growth of the two strains of A. niger was completely inhibited by Carbomar even at the lowest 10 ppm concentration. On the other hand results revealed that phytotoxicity was apparently linked with the type of the fungicide and its concentration. However, the root system was more sensitive to the tested fungicides especially at higher concentrations.     

Antifungal activity of four weedy plant extracts against selected mycotoxigenic fungi

Aims: To investigate the antifungal activity of aqueous and organic extracts of four weedy plant species viz. Tagetes minuta, Lippia javanica, Amaranthus spinosus and Vigna unguiculata against isolates of four agriculturally important fungi, i.e. Fusarium verticillioides, F. proliferatum, Aspergillus flavus and A. parasiticus. Methods and Results: Dried powdered aerial parts of the plants were extracted sequentially with hexane, dichloromethane, methanol and water and tested for activity using a serial microdilution assay. Results were read every day over 120 h. All extracts except for the water extracts showed growth inhibitory activity against most isolates of the Fusarium spp. The most active were the methanol and hexane extracts of V. unguiculata and A. spinosus with minimum inhibitory concentration (MIC) values of <0·5 mg ml^?1 after 48 h against Fusarium spp. No inhibition of the Aspergillus spp. tested was observed, but conidium formation was stimulated on plates treated with plant extracts when visually compared to the growth controls. Conclusions: The results obtained from this study indicated that chemical constituents from these plant species may be developed as potential agrochemical fungicides. Significance and Impact of the Research: Food and feed are subject to infection by a variety of micro‐organisms that can induce spoilage and/or produce metabolites that are toxic to humans and animals. Extracts of V. unguiculata and A. spinosus were most active and maybe developed into environmentally friendly fungicides, which are affordable to rural farmers in developing countries.     

Antifungal activity of some marine organisms from India,against food spoilage Aspergillus strains

Crude aqueous methanol extracts obtained from 31 species of various marine organisms (including flora land faunal), were screened for their antifungal activity against food poisoning strains of Aspergillus. Seventeen species exhibited mild (+ =zone of inhibition 1–2 mm) to significant (+++ =zone of inhibition 3–5 mm) activity against one or the other strain under experiment. However, extracts of 12 species were active against all the three strains. Organisms like Salicornia brachiata(obligate halophyte), Sinularia leptocladus(Soft coral), Elysia grandifolia (Mollusks),Gorgonian sp. 2 and Haliclona sp. exhibited significant (inhibition zone of 3–5 mm) antifungal activity against one or the other strains. However,extracts of A. ilicifolius, Amphiroa sp.,Poryphyra sp., Unidentified sponge, Suberites vestigium, Sinularia compressa,Sunularia sp., Sinularia maxima, Subergorgia suberosa, Echinogorgia pseudorassopo and Sabellaria cementifera were mild (inhibition zone of 1–2 mm) to moderate(inhibition zone of 2–3 mm) active against the respective strains. The growth of A. japonicuswas significantly inhibited by the extracts ofS. leptocladus (r = 0.992, p < 0.0001)and E. grandifolia (r = 0.989, p < 0.0001).This revised version was published online in October 2005 with corrections to the Cover Date.     

In vitro efficacy of some fungicides on mycelial growth of Alternaria alternata and Mucor pyriformis

Various chemical fungicides, systemic and non-systemic, were tested against fruit rot pathogens viz. Alternaria alternata and Mucor pyriformis for the evaluation of inhibition of mycelial growth. In A. alternata, among the systemic fungicides used, hexaconozole showed highest inhibition of mycelial growth followed by carbendazim and least effective was myclobutanil. While in M. pyriformis, hexaconozole showed highest inhibition and least effective was bitertanol. Among the non-systemic fungicides tested in both A. alternata and M. pyriformis, mancozeb showed highest inhibition of mycelial growth followed by capton and the least inhibition was shown by zineb.     

Sexualreaktion und Carotin-Synthese bei Zygomyceten

Zusammenfassung Gamonbildung und Carotinsynthese sind bei den Zygomyceten Mucor mucedo, Blakeslea trispora und Phycomyces Blakesleeanus gekoppelte Reaktionen. Die Gamonbildung verläuft parallel zur Carotinbiosynthese. Damit kann ein Weg zur Klärung der Gamonsynthese gefunden werden.

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Sexual reaction and carotene synthesis in Zygomycetes

Summary In the Zygomycetes Mucor mucedo, Blakeslea trispora and Phycomyces Blakesleeanus, gamon formation and carotene synthesis are coupled reactions. The gamon formation goes parallel with the carotene biosynthesis. This provides a way by which gamon synthesis can be elucidated.

     

Antibacterial dimeric copper(II) complexes with chromone-derived compounds

A new series of six chromone-derived compounds and their Cu(II) complexes have been synthesized and characterized by their physical, spectral and analytical data. The ligands and their Cu(II) complexes were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri) and two Gram-positive (Bacillus subtilis, Staphylococcus aureus) bacterial strains by agar-well diffusion method. The ligands were found to exhibit either no or low-to-moderate activities against one or more bacterial species whereas, the Cu(II) complexes exhibited moderate-to-high activity. The ligands which were inactive before complexation became active upon complexation with the Cu(II) metal ion and less active became more active.     

Success evaluation of the biological control of Fusarium wilts of cucumber,banana, and tomato since 2000 and future research strategies

The Fusarium wilt caused by Fusarium oxysporum strains is the most devastating disease of cucumber, banana, and tomato. The biological control of this disease has become an attractive alternative to the chemical fungicides and other conventional control methods. In this review, the research trends and biological control efficiencies (BCE) of different microbial strains since 2000 are reviewed in detail, considering types of microbial genera, inoculum application methods, plant growth medium and conditions, inoculum application with amendments, and co-inoculation of different microbial strains and how those affect the BCE of Fusarium wilt. The data evaluation showed that the BCE of biocontrol agents was higher against the Fusarium wilt of cucumber compared to the Fusarium wilts of banana and tomato. Several biocontrol agents mainly Bacillus, Trichoderma, Pseudomonas, nonpathogenic Fusarium, and Penicillium strains were evaluated to control Fusarium wilt, but still this lethal disease could not be controlled completely. We have discussed different reasons of inconsistent results and recommendations for the betterment of BCE in the future. This review provides knowledge of the biotechnology of biological control of Fusarium wilt of cucumber, banana, and tomato in a nut shell that will provide researchers a beginning line to start and to organize and plan research for the future studies.     

粮食上木霉菌的分离鉴定及其生防效果

【背景】粮食在生长和收储期极易受到病原真菌或产毒真菌的污染,造成严重的损失。众多实践证明木霉属(Trichoderma)可以有效防治植物病原真菌。【目的】鉴定和筛选能有效抑制粮食常见危害真菌的木霉生防菌株,开发生防菌剂,保障粮食生产安全。【方法】从粮食上分离筛选出35株木霉,通过多基因系统发育分析和形态学观察方法进行菌种鉴定,利用平板对峙试验筛选出对粮食常见危害真菌有抑制作用的菌株。【结果】35株木霉分属于8个种,分别为非洲哈茨木霉(Trichodermaafroharzianum)、类棘孢木霉(Trichodermaasperelloides)、 Trichoderma amoenum、近深绿木霉(Trichoderma paratroviride)、Trichoderma obovatum、长枝木霉(Trichoderma longibrachiatum)、东方木霉(Trichodermaorientale)和深绿木霉(Trichodermaatroviride)。对峙试验结果表明,这8种木霉对于粮食上分离到的10种危害真菌均具有较好的抑制效果。非洲哈茨木霉(T.afroharzi...     

胶州湾沉积物可培养细菌的多样性及其抑菌活性

【目的】海洋微生物在活性物质开发方面具有巨大的应用前景。为了研究胶州湾微生物的多样性和抑菌活性,选取胶州湾9个观测站点的沉积物进行了细菌多样性及抑菌活性分析。【方法】采用YPD和Z2216E培养基分离细菌,通过16S r RNA基因测序对分离菌株进行分类鉴定,继而采用牛津杯法考察分离菌株对7株指示菌的抑菌活性,最后用PCR方法筛选16株代表菌的PKSI、NRPS、CYP、Phz E和d TGD基因。【结果】从胶州湾沉积物中共分离出76株细菌,通过对16S r RNA序列分析,将其归为8个科11个属:节杆菌属、考克氏菌属、微球菌属、微杆菌属、假交替单胞菌属、Oceanisphaera、海单胞菌属、葡萄球菌属、芽孢杆菌属、硫胺素芽孢杆菌属和短芽孢杆菌属,其中分离细菌中有34株至少对1种指示菌有抑菌活性。所选取的16株菌均能检测到一种功能基因,且其中5株菌能同时检测到3种以上的功能基因。【结论】以上研究表明胶州湾海域有丰富的微生物资源,在生物活性次级代谢产物合成上有较大潜力。