scholarly journals Evaluation of selected fungal isolates for the control of Sclerotinia sclerotiorum using cabbage pot bioassays

2005 ◽  
Vol 58 ◽  
pp. 251-255 ◽  
Author(s):  
N. Rabeendran ◽  
E.E. Jones ◽  
D.J. Moot ◽  
A. Stewart
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Field Trials ◽  
Coniothyrium Minitans ◽  
Carpogenic Germination ◽  
The Third ◽  
Fungal Isolates

Nine fungal isolates were assayed for their ability to reduce mycelial infection of cabbage by Sclerotinia sclerotiorum in three pot bioassays In all cases mycelial infection by S sclerotiorum was low However the mycelial inoculum converted into sclerotia which underwent carpogenic germination to produce apothecia In the first pot bioassay four fungal isolates (T hamatum LU594 LU593 and LU592 and T rossicum LU596) reduced the percentage of pots where apothecia were produced Both the number of apothecia produced per pot and the number of pots showing apothecial production were reduced by T hamatum LU593 in the second pot bioassay (by 86 and 76 respectively) In the third bioassay Coniothyrium minitans LU112 was found to completely inhibit apothecial production and T hamatum LU593 reduced both the number of pots with apothecia (by 48) and the total number of apothecia produced per pot (by 72) Both C minitans LU112 and T hamatum LU593 showed the greatest potential for controlling S sclerotiorum disease and these will be tested further in field trials

Efficacy of Antagonists on mycelium growth and carpogenic germination of sclerotia of Sclerotinia sclerotiorum on Indian mustard

2016 ◽  
Vol 1 (02) ◽  
pp. 190-193
Author(s):  
Jhilmil Gupta
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Trichoderma Harzianum ◽  
Plant Pathogens ◽  
Foliar Spray ◽  
Indian Mustard ◽  
Plant Diseases ◽  
Stem Rot ◽  
Pseudomonas Chlororaphis ◽  
Coniothyrium Minitans ◽  
Carpogenic Germination

Sclerotinia sclerotiorum (Lib.) de Bary is a soil borne pathogen capable of infecting more than 400 host plants worldwide. It is a major pathogen that plays a crucial role in reducing the yield in economically important crops. The capability of sclerotia to survive for more than 4 years becomes very difficult to manage the crop from the infection of Sclerotinia rot fungus. Stem rot of indian mustard [Brassica juncea (L.) Czern and Cross] caused by Sclerotinia sclerotiorum is potentially a serious threat in many mustard growing areas in India. Treatments of seeds and foliar spray with of fungicides applied at regular intervals are effective in reducing infection, but uses of chemicals are hazardous, harmful for beneficial micro-organisms. Biological control of plant pathogens offers an exciting opportunity to manage plant diseases. In the present study, the efficacy of four bio-agents, viz., Coniothyrium minitans, Aspergilus nidulans, Trichoderma harzianum, and Pseudomonas chlororaphis were evaluated for the control of stem rot of Indian mustard. Results on bio-efficacy of different bioagents, when evaluated under glass house condition, the Coniothyrium minitans was the most effective agent and caused highest reduction (64.7 %) in carpogenic germination of sclerotia followed by Aspergilus nidulans (52.5 %) and Trichoderma harzianum (48.8 %), over control while Pseudomonas chlororaphis (48.3 %) was at par with T. harzianum. All the bioagents showed significant reduction effective in controlling the disease. Similar results were achieved when bioagents tested on dual inoculated plates.

scholarly journals Californian thistle and its variable response to the biological control agent Sclerotinia sclerotiorum

2016 ◽  
Vol 69 ◽  
pp. 258-262
Author(s):  
B. Smith ◽  
S.G. Casonato ◽  
A. Noble ◽  
G. Bourd?t
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Sclerotinia Sclerotiorum ◽  
Biological Control Agent ◽  
Field Trials ◽  
Control Agent ◽  
Cirsium Arvense ◽  
Variable Response ◽  
Fungal Isolates ◽  
Californian Thistle

Californian thistle (Cirsium arvense) is a problematic weed particularly in permanent pastures The fungus Sclerotinia sclerotiorum has potential as a bioherbicide to control this weed but its variable efficacy in historical field trials suggest that there are differences in susceptibility to S sclerotiorum within the species To test this hypothesis the responses of 32 New Zealand provenances of C arvense to a foliageapplied myceliumonbarley preparation of S sclerotiorum were compared under common conditions Significant differences between provenances were found supporting the hypothesis that there is variation within C arvense in New Zealand in its susceptibility to S sclerotiorum Further work will examine differences in the efficacy of fungal isolates against different C arvense provenances

scholarly journals Co-operative action by endo- and exo-β-(1→3)-glucanases from parasitic fungi in the degradation of cell-wall glucans of Sclerotinia sclerotiorum (Lib.) de Bary

1974 ◽  
Vol 140 (1) ◽  
pp. 47-55 ◽  
Author(s):  
David Jones ◽  
Alex. H. Gordon ◽  
John S. D. Bacon
Keyword(s):  
Cell Wall ◽  
Sclerotinia Sclerotiorum ◽  
Culture Filtrate ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Major Constituent ◽  
Coniothyrium Minitans ◽  
Parasitic Fungi ◽  
Complete Breakdown

1. Two fungi, Coniothyrium minitans Campbell and Trichoderma viride Pers. ex Fr., were grown on autoclaved crushed sclerotia of the species Sclerotinia sclerotiorum, which they parasitize. 2. in vitro the crude culture filtrates would lyse walls isolated from hyphal cells or the inner pseudoparenchymatous cells of the sclerotia, in which a branched β-(1→3)-β-(1→6)-glucan, sclerotan, is a major constituent. 3. Chromatographic fractionation of the enzymes in each culture filtrate revealed the presence of several laminarinases, the most active being an exo-β-(1→3)-glucanase, known from previous studies to attack sclerotan. Acting alone this brought about a limited degradation of the glucan, but the addition of fractions containing an endo-β-(1→3)-glucanase led to almost complete breakdown. A similar synergism between the two enzymes was found in their lytic action on cell walls. 4. When acting alone the endo-β-(1→3)-glucanase had a restricted action, the products including a trisaccharide, tentatively identified as 62-β-glucosyl-laminaribiose. 5. These results are discussed in relation to the structure of the cell walls and of their glucan constituents.

scholarly journals Treatment of overwintering apple leaves to reduce primary inoculum of apple black spot

2003 ◽  
Vol 56 ◽  
pp. 95-99
Author(s):  
K. Tshomo ◽  
I.J. Horner ◽  
M. Walter ◽  
A. Stewart ◽  
M.V. Jaspers
Keyword(s):  
Venturia Inaequalis ◽  
Black Spot ◽  
Field Trials ◽  
Water Control ◽  
Primary Inoculum ◽  
Apple Leaves ◽  
Fungal Isolates ◽  
Glass Slides ◽  
Ascospore Production ◽  
Nutrient Amendments

Field trials were conducted in Hawkes Bay and Lincoln into methods of treating overwintering apple leaves to reduce ascospore production by the apple black spot pathogen Venturia inaequalis The leaf treatments comprised three levels of nutrient amendments (including a water control) and five levels of saprophytic fungal isolates (including a nofungus control) in a factorial design Leaves were left to overwinter on the orchard floor and in spring the V inaequalis ascospores released were trapped on glass slides and counted Ascospore numbers were reduced (Plt;005) by the leaf amendment urea which alone caused 73 reduction but not by the BioStarttrade; product The effect of fungal isolates was not significant (P012) although when combined with the water treatment the isolates Chaetomium Phoma and Epicoccum spp and Trametes versicolor reduced numbers of ascospores by 33 27 15 and 28 respectively compared to the nofungus control When combined with urea the Chaetomium isolate reduced ascospore numbers by 92 and 82 compared to the nil fungus/water control treatments in Hawkes Bay and Lincoln respectively indicating that this treatment has potential for reducing primary inoculum of apple black spot

scholarly journals Favorable Bioactivity of the SDHI Fungicide Benzovindiflupyr Against Sclerotinia sclerotiorum Mycelial Growth, Sclerotial Production, and Myceliogenic and Carpogenic Germination of Sclerotia

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1613-1620 ◽  
Author(s):  
Xue-ping Huang ◽  
Jian Luo ◽  
Yu-fei Song ◽  
Bei-xing Li ◽  
Wei Mu ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Baseline Sensitivity ◽  
Carpogenic Germination ◽  
Alternative Product ◽  
Application Potential ◽  
New Generation

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a prevalent plant pathogen. This study aims to evaluate the application potential of benzovindiflupyr, a new generation of succinate dehydrogenase inhibitor (SDHI), against S. sclerotiorum. In our study, 181 isolates collected from different crops (including eggplant [n = 34], cucumber [n = 27], tomato [n = 29], pepper [n = 35], pumpkin [n = 32], and kidney bean [n = 25]) in China were used to establish baseline sensitivity to benzovindiflupyr. The frequency distribution of the 50% effective concentration (EC50) values of benzovindiflupyr was a unimodal curve, with mean EC50 values of 0.0260 ± 0.011 μg/ml, and no significant differences in mean EC50 existed among the various crops (P > 0.99). Benzovindiflupyr can effectively inhibit mycelial growth, sclerotial production, sclerotial shape, and myceliogenic and carpogenic germination of the sclerotia of S. sclerotiorum. In addition, benzovindiflupyr showed good systemic translocation in eggplant. Using benzovindiflupyr at 100 μg/ml yielded efficacies of 71.3 and 80.5% for transverse activity and cross-layer activity, respectively, which were higher than those of acropetal and basipetal treatments (43.6 and 44.7%, respectively). Greenhouse experiments were then carried out at two experimental sites for verification. Applying benzovindiflupyr at 200 g a.i. ha−1 significantly reduced the disease incidence and severity of Sclerotinia stem rot. Overall, the results demonstrated that benzovindiflupyr is a potential alternative product to control Sclerotinia stem rot.

scholarly journals Carpogenic Germinability of Diverse Sclerotinia sclerotiorum Populations Within the Southwestern Australian Grain Belt

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2891-2897
Author(s):  
Pippa J. Michael ◽  
King Yin Lui ◽  
Linda L. Thomson ◽  
Katia Stefanova ◽  
Sarita J. Bennett
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Temperature Fluctuations ◽  
Sclerotinia Stem Rot ◽  
Dark Cycle ◽  
Diurnal Temperature ◽  
Population Responses ◽  
Carpogenic Germination ◽  
Southwestern Australia ◽  
Temperature Regimes ◽  
Mycelial Compatibility

Sclerotinia stem rot, caused by the necrotrophic plant pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease of canola and pulses in Australia. Current disease management relies greatly on cultural and chemical means of control. Timing of fungicide applications remains a challenge, because efficacy is dependent on accurate prediction of ascospore release and presence on the plant. The aims of this study were to determine the optimal temperature for carpogenic germination of S. sclerotiorum populations sampled from canola and lupin fields in southwestern Australia and characterize diversity using mycelial compatibility groupings (MCGs). Sclerotia were collected from four diseased canola and one diseased lupin field from across southwestern Australia. Forty sclerotia from each population were incubated at four alternating temperatures of 30/15, 20/15, 20/4, and 15/4°C (12-h/12-h light/dark cycle) and assessed every 2 to 3 days for a 180-day period. MCG groupings for populations were characterized using 12 reference isolates. Results indicated the time to initial carpogenic germination decreased as diurnal temperature fluctuations decreased, with a fluctuation of 5°C (20/15°C) having the most rapid initial germination followed by 11°C (15/4°C) followed by 16°C (20/4°C). Optimal germination temperature for all five populations was 20/15°C; however, population responses to other diurnal temperature regimes varied considerably. No germination was observed at 30/15°C. MCG results indicate extensive diversity within and between populations, with at least 40% of sclerotia within each population unable to be characterized. We suggest that this diversity has enabled S. sclerotiorum populations to adapt to varying environmental conditions within southwestern Australia.

Sensitivity of Ulocladium atrum, Coniothyrium minitans, and Sclerotinia sclerotiorum to benomyl and vinclozolin

2002 ◽  
Vol 80 (8) ◽  
pp. 892-898 ◽  
Author(s):  
G Q Li ◽  
H C Huang ◽  
S N Acharya
Keyword(s):  
Growth Inhibition ◽  
Sclerotinia Sclerotiorum ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Germination Rate ◽  
Effective Concentration ◽  
Coniothyrium Minitans ◽  
Inhibition Concentration ◽  
Maximum Inhibition ◽  
Germ Tubes

Assays on mycelial growth and spore germination were carried out to determine the sensitivity of the biocontrol agents Ulocladium atrum and Coniothyrium minitans and the plant pathogen Sclerotinia sclerotiorum to benomyl and vinclozolin. Ulocladium atrum was more tolerant to these fungicides than C. minitans and S. sclerotiorum. The 50% effective concentration (EC50) of U. atrum based on the mycelial growth inhibition was 1467.3 µg active ingredient (a.i.)/mL for benomyl and 12.6 µg a.i./mL for vinclozolin, and the maximum inhibition concentration was higher than 4000 µg a.i./mL for both fungicides. For C. minitans and S. sclerotiorum, however, the EC50 based on mycelial growth inhibition was lower than 1 µg a.i./mL. After incubation for 24 h at 20°C, the germination rate of U. atrum conidia was 90–99% on potato dextrose agar (PDA) amended with benomyl at 100–500 µg a.i./mL or vinclozolin at 10–500 µg a.i./mL. At these concentrations, germ tubes of U. atrum developed into long, branched hyphae in benomyl treatments, but they remained short and clustered in vinclozolin treatments. Pycnidiospores of C. minitans and ascospores of S. sclerotiorum germinated on PDA amended with benomyl at 100–500 µg a.i./mL, but the germ tubes did not grow further. Spore germination of C. minitans and S. sclerotiorum was less than 3.2% on PDA amended with vinclozolin at 10–500 µg a.i./mL after 24 h. This is the first report on the sensitivity of U. atrum and C. minitans to benomyl and vinclozolin. The results suggest that it is possible to control S. sclerotiorum using a combination of U. atrum and benomyl or vinclozolin.Key words: fungicides, mycelial growth, spore germination, integrated pest management.

scholarly journals Host Transcriptional Response of Sclerotinia sclerotiorum Induced by the Mycoparasite Coniothyrium minitans

2020 ◽  
Vol 11 ◽  
Author(s):  
Huizhang Zhao ◽  
Ting Zhou ◽  
Jiatao Xie ◽  
Jiasen Cheng ◽  
Daohong Jiang ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Transcriptional Response ◽  
Coniothyrium Minitans

Shot-hole borer (Xyleborus fornicatus Eichh.) of tea in Ceylon II.—The effect of chemical control on the yield and manurial response of tea

1968 ◽  
Vol 57 (4) ◽  
pp. 619-641
Author(s):  
J. E. Cranham ◽  
P. Kanapathapillai ◽  
A. Kathiravetpillai
Keyword(s):  
Field Trials ◽  
First Year ◽  
Percentage Increase ◽  
Nitrogen Application ◽  
The Third ◽  
Prolonged Effect ◽  
Second Year ◽  
The Difference ◽  
Significant Regression ◽  
Effect On Yield

In 1960–65, six field trials were carried out on tea estates in Ceylon to assess the effect on yield, and on the response of the crop to fertilizer, of dieldrin sprays applied after pruning to control shot-hole borer (Xyleborus fornicatus Eichh.). Periodic sampling was carried out to assess the numbers of borers and their galleries. Yields were recorded by weekly or fortnightly weighings of the green leaf plucked, over pruning cycles of two to four years.The pattern of the yield increases on the sprayed plots was related to the difference in attack between the sprayed and unsprayed plots. Increases were, in general, small in the first year and much larger in the second year, reaching peak values of 32–58 per cent. (on the yields of successive three-monthly periods recorded) in the late second year, and declining thereafter through the third year as the difference in attack declined. Over the first two years there were marked yield increases in eight of the nine pruning cycles, and these ranged from 11·7 per cent, to 26·3 per cent. There was significant regression (P<0·001) of the percentage increase in yield on the maximum difference in gallery counts. Yield increases in the third year of pruning cycles were also considerable and the results evidence a prolonged effect of the heavy borer attack occurring in the second year.In one trial there was a significant interaction between the effects of dieldrin spraying and of nitrogen supplied. Control of the borer greatly improved the crop response to nitrogen. Nitrogen application increased the yield but resulted also in a proportionately larger loss of crop from borer attack. There was a small but significant increase in the number of borer galleries on the plots receiving nitrogen.The evidence on the size and pattern of crop losses caused by the borer suggests that these occur both from shoot breakages and from the direct effect of galleries on the growth of stems.The significance of the results in relation to estate practice, and the economics of spraying, are briefly discussed.

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