scholarly journals Peroxyacetic Acid (PAA): an eco-friendly Agent for Reducing Sclerotinia sclerotiorum Growth, Sclerotia Carpogenic Germination and Infectivity

2017 ◽  
Vol 45 (2) ◽  
pp. 67-78
Author(s):  
Ranya El-Ashmony ◽  
Marzouk Abdel-Latif ◽  
El-Sayed Abdou ◽  
Anwar Galal
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Peroxyacetic Acid ◽  
Carpogenic Germination

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.

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.

SCLEROTINIA HEAD ROT IN SAFFLOWER: ASSESSMENT OF RESISTANCE AND EFFECTS ON YIELD AND OIL CONTENT

1985 ◽  
Vol 65 (2) ◽  
pp. 259-265 ◽  
Author(s):  
H. -H. MÜNDEL ◽  
H. C. HUANG ◽  
G. C. KOZUB
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Oil Content ◽  
Field Experiments ◽  
Growing Season ◽  
Carthamus Tinctorius ◽  
Yield Losses ◽  
Carpogenic Germination ◽  
Early Maturing ◽  
Parental Lines ◽  
Head Rot

Field experiments were conducted in 1982 and 1983 to screen 20 lines of safflower (Carthamus tinctorius L.) for resistance to head rot caused by Sclerotinia sclerotiorum (Lib.) de Bary. Plots were artificially infested with sclerotia of S. sclerotiorum at seeding and irrigated during the growing season to maintain adequate moisture for carpogenic germination of sclerotia and production of apothecia. The reaction of each line to S. sclerotiorum was similar for the 2 years. Severity of head rot varied significantly among the 20 lines tested, ranging from 6% for Lesaf 34C-OO to 62% for Gila in 1982 and from 0.3% for Lesaf 34C-OO to 31% for PCA in 1983. Level of resistance was not related to the level of maturity of the lines. Yield losses ranged from 81 kg/ha for Lesaf 34C-OO to 678 kg/ha for Gila in 1982 and from 14 kg/ha for Lesaf 34C-OO to 935 kg/ha for PCA in 1983. Healthy plants averaged 4.4% more oil in the seed than did the corresponding parental lines. This study has demonstrated the possibility of developing early maturing safflower lines resistance to sclerotinia head rot for production on the Canadian Prairies.Key words: Carthamus tinctorius, Sclerotinia sclerotiorum

scholarly journals Effects of Soil Temperature, Moisture, and Burial Depths on Carpogenic Germination of Sclerotinia sclerotiorum and S. minor

2008 ◽  
Vol 98 (10) ◽  
pp. 1144-1152 ◽  
Author(s):  
B. M. Wu ◽  
K. V. Subbarao
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Sclerotinia Sclerotiorum ◽  
Soil Water Potential ◽  
Conventional Tillage ◽  
Dry Period ◽  
Carpogenic Germination ◽  
Needed Information ◽  
Geographical Regions ◽  
Soil Temperature And Moisture

Extensive studies have been conducted on the carpogenic germination of Sclerotinia sclerotiorum, but carpogenic germination in S. minor has not been studied adequately. It remains unclear why apothecia of this pathogen have seldom been observed in nature. In this study, a new method was developed to produce apothecia in the absence of soil or sand, and carpogenic germination without preconditioning was recorded for 95 of the 96 S. sclerotiorum isolates tested. Carpogenic germination of the two species was compared under a variety of temperature, soil moisture, burial depths, and short periods of high temperature and low soil moisture. The optimal temperatures for rapid germination and for maximum germination rates were both lower for S. minor than for S. sclerotiorum. The temperature range for carpogenic germination was also narrower for S. minor than for S. sclerotiorum. A 5-day period at 30°C, either starting on the 10th or 20th day of incubation, did not significantly affect carpogenic germination of S. sclerotiorum. For both S. minor and S. sclerotiorum, the percentage of carpogenically germinated sclerotia increased as soil water potential increased from –0.3 to –0.01 MPa. In the greenhouse, a 10- or 20-day dry period completely arrested carpogenic germination of S. sclerotiorum, and new apothecia appeared after an interval of 35 days following rewetting, similar to the initial carpogenic germination regardless of when the dry period was imposed. In naturally infested fields, the number of sclerotia in 100 cc of soil decreased as depth increased from 0 to 10 cm before tillage, but became uniform between 0 and 10 cm after conventional tillage for both species. Most apothecia of S. minor were, however, produced from sclerotia located at a depth shallower than 0.5 cm while some apothecia of S. sclerotiorum were produced from sclerotia located as deep as 4 to 5 cm. These results provide the much needed information to assess the epidemiological roles of inoculum from sexual reproduction in diseases caused by the two Sclerotinia species in different geographical regions. However, more studies on effects of shorter and incompletely dry periods are still needed to predict production of apothecia of S. sclerotiorum in commercial fields under fluctuating soil temperature and moisture.

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

scholarly journals Effect of Sclerotial Water Content on Carpogenic Germination of Sclerotinia sclerotiorum

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1315-1322 ◽  
Author(s):  
Achala Nepal ◽  
Luis E. del Río Mendoza
Keyword(s):  
Moisture Content ◽  
Sclerotinia Sclerotiorum ◽  
Water Saturation ◽  
Sandy Loam ◽  
Sandy Soils ◽  
Controlled Environment ◽  
Silty Clay ◽  
Carpogenic Germination ◽  
Water Imbibition ◽  
The Relationship

The relationship between moisture content and carpogenic germination (CG) of Sclerotinia sclerotiorum sclerotia and the dynamics of sclerotial water imbibition were studied in a controlled environment. The study was conducted using laboratory-produced sclerotia from seven S. sclerotiorum isolates. The quantity and rate of water imbibition by three sizes of sclerotia was determined gravimetrically in silty clay, sandy loam, and sandy soils maintained at 100, 75, 50, and 25% of soil saturation and in distilled water. Smaller sclerotia imbibed water at a significantly faster rate (P = 0.05) than larger sclerotia in water and in soil at all saturation percentages. When buried in soil, small, medium, and large sclerotia were fully saturated within 5, 15, and 25 h, respectively, in all three soil types and moisture percentages. The effect of sclerotia moisture content on CG was evaluated on sclerotia maintained at 95 to 100, 70 to 80, 40 to 50, and 20 to 30% of their water saturation capacity using cool mist humidifiers. Sclerotial moisture content significantly influenced CG (P = 0.05). Maximum CG was observed on fully saturated sclerotia, while no CG was observed below 70 to 80% of saturation. These findings help explain S. sclerotiorum's ability to produce apothecia in soils with relatively low moisture levels.

scholarly journals Forecasting Sclerotinia Disease on Lettuce: A Predictive Model for Carpogenic Germination of Sclerotinia sclerotiorum Sclerotia

2007 ◽  
Vol 97 (5) ◽  
pp. 621-631 ◽  
Author(s):  
John P. Clarkson ◽  
Kath Phelps ◽  
John M. Whipps ◽  
Caroline S. Young ◽  
Julie A. Smith ◽  
...  
Keyword(s):  
Predictive Model ◽  
Sclerotinia Sclerotiorum ◽  
Soil Water Potential ◽  
Disease Forecasting ◽  
Conditioning Phase ◽  
Temperature Dependent ◽  
Carpogenic Germination ◽  
Temperature Thresholds ◽  
Forecasting System ◽  
Potential Threshold

A predictive model for production of apothecia by carpogenic germination of sclerotia is presented for Sclerotinia sclerotiorum. The model is based on the assumption that a conditioning phase must be completed before a subsequent germination phase can occur. Experiments involving transfer of sclerotia from one temperature regime to another allowed temperature-dependent rates to be derived for conditioning and germination for two S. sclerotiorum isolates. Although the response of each isolate to temperature was slightly different, sclerotia were fully conditioned after 2 to 6 days at 5°C in soil but took up to 80 days at 15°C. Subsequent germination took more than 200 days at 5°C and 33 to 52 days at 20°C. Upper temperature thresholds for conditioning and germination were 20 and 25°C, respectively. A predictive model for production of apothecia derived from these data was successful in simulating the germination of multiple burials of sclerotia in the field when a soil water potential threshold of between −4.0 and −12.25 kilopascals (kPa) was imposed. The use of a germination model as part of a disease forecasting system for Sclerotinia disease in lettuce is discussed.

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