scholarly journals In vitro evaluation of fungicides and biocontrol agents for efficacy against Neofusicoccum spp that cause dieback of blueberries

2014 ◽  
Vol 67 ◽  
pp. 323-323
Author(s):  
K.M.S. Tennakoon ◽  
H.J. Ridgway ◽  
E.E. Jones ◽  
M.V. Jaspers
Keyword(s):  
Mycelial Growth ◽  
Germ Tube ◽  
Stem Canker ◽  
Conidial Germination ◽  
Biocontrol Agents ◽  
Dual Plate ◽  
Twig Blight ◽  
Different Parts ◽  
Germ Tube Elongation

Several botryosphaeriaceous species have been reported to cause stem canker twig blight and dieback of blueberries with different Botryosphaeria species reported in different parts of the world This research evaluated nine fungicides for their ability to reduce mycelial growth conidial germination and germ tube elongation of four common and pathogenic botryosphaeriaceous species recovered from New Zealand blueberries Furthermore two biocontrol agents were tested against the same species using dual plate assays Fludioxonil carbendazim flusilazole and tebuconazole were the most effective for inhibition of mycelial growth of three isolates each of Neofusicoccum australe N luteum N parvum and N ribis EC50 values for these fungicides were less than 01 mg ai/litre Carbendazim and iprodione (both EC50 004 mg/litre) were the most effective for reduction of conidial germination of all four species In addition these two fungicides were effective for inhibition of germ tube elongation with mean EC50 values of 004 and 01 mg/litre respectively The biocontrol agents Trichoderma atroviride and Bacillus subtilis reduced mycelial growth of all species tested with a range of macroscopic interactions This study has indicated the most promising fungicides and biocontrol agents for further investigations to protect pruning wounds in blueberries

scholarly journals Saprophytic microorganisms with potential for biological control of Botrytis cinerea on Geraldton waxflower flowers

2001 ◽  
Vol 41 (5) ◽  
pp. 697 ◽  
Author(s):  
D. R. Beasley ◽  
D. C. Joyce ◽  
L. M. Coates ◽  
A. H. Wearing
Keyword(s):  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Conidial Germination ◽  
Pseudomonas Sp ◽  
Trichoderma Spp ◽  
Fusarium Sp ◽  
Flower Abscission ◽  
Germ Tube Elongation

Saprophytic bacteria, yeasts and filamentous fungi were isolated from Geraldton waxflower flowers and screened to identify potential antagonism towards Botrytis cinerea. Isolates from other sources (e.g. avocado) were also tested. Isolates were initially screened in vitro for inhibition of B. cinerea conidial germination, germ tube elongation and mycelial growth. The most antagonistic bacteria, yeasts and fungi were selected for further testing on detached waxflower flowers. Conidia of the pathogen were mixed with conidia or cells of the selected antagonists, co-inoculated onto waxflower flowers, and the flowers were sealed in glass jars and incubated at 20˚C. The number of days required for the pathogen to cause flower abscission was determined. The most antagonistic bacterial isolate, Pseudomonas sp. 677, significantly reduced conidial germination and retarded germ tube elongation of B. cinerea. None of the yeast or fungal isolates tested was found to significantly reduce conidial germination or retard germ tube elongation, but several significantly inhibited growth of B. cinerea. Fusarium sp., Epicoccum sp. and Trichoderma spp. were the most antagonistic of these isolates. Of the isolates tested on waxflower, Pseudomonas sp. 677 was highly antagonistic towards B. cinerea and delayed waxflower abscission by about 3 days. Trichoderma harzianum also significantly delayed flower abscission. However, as with most of the fungal antagonists used, inoculation of waxflower flowers with this isolate resulted in unsightly mycelial growth.

scholarly journals Diffusible Compounds Produced by Hanseniaspora osmophila and Gluconobacter cerinus Help to Control the Causal Agents of Gray Rot and Summer Bunch Rot of Table Grapes

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 664
Author(s):  
Matías Olivera ◽  
Ninoska Delgado ◽  
Fabiola Cádiz ◽  
Natalia Riquelme ◽  
Iván Montenegro ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Biocontrol Agents ◽  
Environmental Cost ◽  
Antifungal Compounds ◽  
Table Grapes ◽  
Dual Cultures ◽  
Bunch Rot ◽  
Direct Bioautography

Gray and summer bunch rot are important diseases of table grapes due to the high economic and environmental cost of their control with synthetic fungicides. The ability to produce antifungal compounds against the causal agents Botrytis, Aspergillus, Penicillium, and Rhizopus of two microorganisms isolated from table grapes and identified as Hanseniaspora osmophila and Gluconobacter cerinus was evaluated. In dual cultures, both biocontrol agents (together and separately) inhibited in vitro mycelial growth of these pathogens. To identify the compounds responsible for the inhibitory effect, extractions were carried out with organic solvents from biocontrol agents separately. Through dual cultures with pathogens and pure extracts, only the hexane extract from H. osmophila showed an inhibitory effect against Botrytis cinerea. To further identify these compounds, the direct bioautography technique was used. This technique made it possible to determine the band displaying antifungal activity at Rf = 0.05–0.2. The compounds present in this band were identified by GC-MS and compared to the NIST library. The most abundant compounds, not previously reported, corresponded to alkanes, ketones, alcohols, and terpenoids. H. osmophila and G. cerinus have the potential to control the causal agents of gray and summer bunch rot of table grapes.

scholarly journals Antifungal Efficacy of Plant Oils Containing Thymol and Carvacrol in Controlling Botrytis cinerea, the Causal Agent of Grape (Vitis vinifera) GrayMould

2018 ◽  
Vol 16 (02) ◽  
pp. 15-24
Author(s):  
Zaker M ◽  
Zaker L
Keyword(s):  
Essential Oils ◽  
Botrytis Cinerea ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Plant Diseases ◽  
Plant Oils ◽  
Horticultural Products ◽  
Antifungal Efficacy ◽  
Germ Tube Elongation

The efficacy of a large number of plant extracts and essential oils in controlling plant diseases has been proven worldwide. Botrytis cinerea has attacked a wide host range causing severe loss in the field and at storage. In this study the antifungal efficacy of essential oils of three medicinal plants namely wild marjoram (Zataria multifolia), wild savory (perennial) (Satureja mutica) and savory (annual) (Satureja hortensis) possessing these compounds at three concentrations: 50, 100 and 200 ppm were evaluated in controlling the mycelial growth, spore germination and germ tube elongation of B. cinerea. All treatments except savory (annual) essential oil at 50 ppm showed significant differences with the control in inhibiting the mycelial growth as well as spore germination and germ tube elongation of B. cinerea (p=0.01). It was also noted that wild marjoram at 100 ppm and wild savory (perennial) essential oils at 200 ppm could completely (100%) inhibit the growth of the fungus. Essential oils from wild marjoram and wild savory had higher antifungal activity than annual savory. Their suitable formulations could be prepared and used as safe alternatives for controlling moulds of horticultural products during storage. The Agriculturists 2018; 16(2) 15-24

scholarly journals Control of Sphaeropsis Rot in Stored Apple Fruit Caused by Sphaeropsis pyriputrescens with Postharvest Fungicides

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1075-1079 ◽  
Author(s):  
C. L. Xiao ◽  
Y. K. Kim ◽  
R. J. Boal
Keyword(s):  
Mycelial Growth ◽  
Disease Incidence ◽  
Apple Fruit ◽  
Conidial Germination ◽  
Fruit Rot ◽  
Mitigation Measures ◽  
The Mean ◽  
Rot Disease ◽  
Sphaeropsis Rot

Sphaeropsis rot caused by Sphaeropsis pyriputrescens is a recently reported postharvest fruit rot disease of apple grown in Washington State. The objective of this study was to develop chemical-based mitigation measures for Sphaeropsis rot in stored apple fruit. To determine in vitro sensitivity of S. pyriputrescens to the three registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil, 30 isolates of S. pyriputrescens obtained from various sources were tested for mycelial growth and conidial germination on fungicide-amended media. Golden Delicious apple fruit were inoculated with the pathogen in the orchard at 2 or 5 weeks before harvest. After harvest, fruit were either nontreated or dipped in thiabendazole, fludioxonil, or pyrimethanil solutions, stored at 0°C, and monitored for decay development for up to 9 months after harvest. The mean effective concentration of a fungicide that inhibits mycelial growth or spore germination by 50% relative to the nonamended control (EC50) values of thiabendazole, fludioxonil, and pyrimethanil on mycelial growth were 0.791, 0.0005, and 2.829 μg/ml, respectively. Fludioxonil and pyrimethanil also were effective in inhibiting conidial germination of the fungus with EC50 values of 0.02 μg/ml for fludioxonil and 5.626 μg/ml for pyrimethanil. All three postharvest fungicides applied at label rates immediately after harvest were equally effective in controlling Sphaeropsis rot in stored apple fruit, reducing disease incidence by 92 to 100% compared with the nontreated control. The results indicated that Sphaeropsis rot may be effectively controlled by the currently registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil.

scholarly journals Effects of biocontrol agents and plant products Macrophomina phaseolina and colchicine content in Gloriosa superba

2012 ◽  
Vol 48 (No. 3) ◽  
pp. 110-115 ◽  
Author(s):  
D. Alice ◽  
S. Sundravadana
Keyword(s):  
Mycelial Growth ◽  
Foliar Application ◽  
Trichoderma Viride ◽  
Macrophomina Phaseolina ◽  
Biocontrol Agents ◽  
Gloriosa Superba ◽  
Healthy Growth ◽  
Rot Disease ◽  
Tuber Rot

Gloriosa superba is a medicinal plant severely infested with soil-borne Macrophomina phaseolina (Tassi) Goid. Under in vitro conditions a commercial formulation of Trichoderma viride and Pseudomonas fluorescens inhibited the mycelial growth of M. phaseolina isolates. Among the oil cake, mahua cake at 10% completely inhibited the mycelial growth of the M. phaseolina isolates. Under field conditions both the soil and foliar application of biocontrol agents is attributed to the healthy growth of G. superba crops by controlling the tuber rot disease and ultimately boosting the colchicine content.

ENZYME ACTIVITIES DURING THE ASEXUAL CYCLE OF NEUROSPORA CRASSA: I. SUCCINIC DEHYDROGENASE

1967 ◽  
Vol 13 (9) ◽  
pp. 1203-1210 ◽  
Author(s):  
G. J. Stine
Keyword(s):  
Neurospora Crassa ◽  
Enzyme Activities ◽  
Soluble Protein ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Succinic Dehydrogenase ◽  
Growth Yield ◽  
Conidial Germination ◽  
Germination And Growth ◽  
Asexual Cycle

Separate extracts of Neuorospora crassa grown either in Vogel's medium N, medium N + glutamate, or medium N which had been made deficient in zinc, were assayed for succinic dehydrogenase and soluble protein at intervals throughout the asexual cycle. Succinic dehydrogenase, although apparently unnecessary for either the formation of conidia or conidial germination, does appear to be necessary for mycelial growth and for the production of conidiophores. Differences in the amount of enzyme during morphologically distinct states of differentiation (i.e. production of the germ tube and production of the conidiophore) may serve as an indicator of significant changes in the physiology of Neurospora at these times during development.The level of succinic dehydrogenase in the conidiophore before its differentiation into conidia appears to influence the amount of this enzyme found in the conidia. This is in keeping with the idea that conditions prevailing in the cytoplasm before the formation of conidia may directly influence the constituents subsequently found in the conidia which determine conidial viability, rate of germination, and growth yield.

Antagonistic interactions of phylloplane bacteria with Drechslera dictyoides (Drechsler) Shoemaker

1977 ◽  
Vol 23 (6) ◽  
pp. 710-715 ◽  
Author(s):  
Brian Austin ◽  
Colin H. Dickinson ◽  
Michael Goodfellow
Keyword(s):  
Lolium Perenne ◽  
Xanthomonas Campestris ◽  
Germ Tube ◽  
Disease Symptoms ◽  
In Vivo Experiments ◽  
Drechslera Dictyoides ◽  
Antagonistic Interactions ◽  
Germ Tube Elongation

Strains of Listeria denitrificans (E2), Psendomonas fluorescens (C37 and C92), and Xanthomonas campestris (D119), isolated from the phylloplane of Lolium perenne (S24), were antagonistic to Drechslera dictyoides (Drechsler) Shoemaker. From in vitro and in vivo experiments it was deduced that their mode of activity included an initial inhibition of spore germination, a retardation in the rate of germ-tube elongation, and ultimately lysis of the hyphae. The effects were expressed on the plant in terms of reduced levels of disease symptoms and sporulation.

scholarly journals Baseline Sensitivity of Guignardia citricarpa Isolates from Florida to Azoxystrobin and Pyraclostrobin

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 780-789 ◽  
Author(s):  
Martha Hincapie ◽  
Nan-Yi Wang ◽  
Natalia A. Peres ◽  
Megan M. Dewdney
Keyword(s):  
Mycelial Growth ◽  
Control Measure ◽  
Black Spot ◽  
Conidial Germination ◽  
Baseline Sensitivity ◽  
Qoi Fungicides ◽  
Resistance Risk ◽  
Guignardia Citricarpa ◽  
The Mean

Citrus black spot (CBS), caused by Guignardia citricarpa, is an emerging disease in Florida. Fungicide applications are the main control measure worldwide. The in vitro activity and baseline sensitivity of G. citricarpa isolates to quinone outside inhibitor (QoI) fungicides (azoxystrobin and pyraclostrobin) were evaluated. The effective concentration needed to reduce mycelial growth or spore germination by 50% (EC50) was determined for 86 isolates obtained from Florida counties where CBS is found. The effect of salicylhydroxamic acid (SHAM) plus azoxystrobin and pyraclostrobin was also assessed for mycelial growth and conidial germination. The mean EC50 for mycelial growth for azoxystrobin was 0.027 μg/ml and that for pyraclostrobin was significantly lower at 0.007 μg/ml (P < 0.0001). Similarly, the mean EC50 for conidial germination for azoxystrobin was 0.016 μg/ml and that for pyraclostrobin was significantly lower at 0.008 μg/ml (P < 0.0001). There was no effect of SHAM on inhibition of mycelial growth or conidial germination by the QoI fungicides but SHAM slightly affected mycelium inhibition by pyraclostrobin. Cytochrome b was partially sequenced and three group 1 introns were found. One intron was immediately post G143, likely inhibiting resistance-conferring mutations at that site. It is surmised that the QoI resistance risk is low in the Florida G. citricarpa population.

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