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Collapsed vines of sweet potato (Ipomoea batatas) plants were observed in Jining fields in September 2019. In some cases, the whole plant had been killed due to the infection of crown. The size of sclerotia formed on infected tissues ranged from 0.6 to 1.5 cm in diameter. A number of sclerotia were sampled from infected fields and transferred to laboratory. After molecular assessment of the isolate SSd925 and fulfillment of Koch's Postulates, the pathogen was identified as Sclerotinia sclerotiorum. To our knowledge, this is the first report of S. sclerotiorum on sweet potato in China. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the inhibitory effect of pimaricin against Sclerotinia sclerotiorum, the causal agent of potato white mould. Field trials in 2016 and 2017 were conducted in Bahar and Lalehjin, Hamedan, Iran. Pimaricin at the concentration of 200 mg/L was able to reduce the disease incidence during field trials. The concentration of 2.5 mg/L completely inhibited the radial growth and sclerogenesis of three tested isolates of S. sclerotiorum. In addition, pimaricin at the concentration of 2.5 mg/L reduced the carpogenic germination of sclerotia in isolates 1, 2 and 3 by 100%, 88.1% and 73.9%, respectively. Treatment with pimaricin at the concentration of 2 mg/L for 160 min enhanced relative conductivity of S. sclerotiorum mycelia up to 100%. The concentration of 2 mg/L increased the cell membrane permeability of mycelia more than the concentration of 1 mg/L over 160 min. Moreover, exposure to pimaricin at the concentration of 2 mg/L for 12 hr increased carbohydrate leakage of the pathogen mycelia up to 73%. Pimaricin at the concentration of 2 mg/L markedly increased the content of methane dicarboxylic aldehyde (MDA) over time, and the highest content of MDA was recorded as 5.9 µmol/kg FW after 20 hr. The percentage of catalase activity was reduced in the pathogen mycelia by 4.1 U g−1 min−1 after exposure to pimaricin at the concentration of 2 mg/L for 20 min. [ABSTRACT FROM AUTHOR]

This study was carried out to determine inhibitory effect of crude extracts and essential oils of aromatic plants against Sclerotinia sclerotiorum in potato fields in Bahar and Lalehjin, Iran during cropping seasons of 2015 and 2016. The results showed that crude extracts of cinnamon and ginger at concentrations 5 g/l as well as essential oils of coriander, lavender thyme, savory and eucalyptus at concentration 50 μl EO/ml had potential to significantly reduce incidence of potato white mold. This is the first study about inhibitory effect of crude extracts and essential oils of aromatic plants against potato white mold under field condition. [ABSTRACT FROM AUTHOR]

During plant diseases evaluation of Hangzhou, a city on south east of China, in September 2017, water-soaked lesions were observed in lower parts of potato plants near the soil in a few fields. In addition, mature black sclerotia were found inside dried out beige lesions. A number of sclerotia were sampled from infected fields and transferred to laboratory. After assessment of myceliogenic and carpogenic germination as well as Koch's Postulates, the pathogen was identified as Sclerotinia sclerotiorum. To our knowledge, this is the first report of S. sclerotiorum on potato in China. [ABSTRACT FROM AUTHOR]

Potato white mold caused by Sclerotinia sclerotiorum is an important plant disease occurring in many potato-producing areas throughout the world. In this study, a specific diagnostic method was used to detect and quantify S. sclerotiorum ascospores, and its forecasting ability was assessed in potato fields during flowering periods of 2011 to 2014 in Bahar County, Hamedan Province. Using GenEMBL database, a primer pair, HZSCREV and HZSCFOR, was designed and optimized for the pathogen. After testing the sensitivity of primers, DNA was extracted from samples of outdoor Burkard traps from potato fields. A linear association was observed between pathogen DNA and the number of ascospores using the quantitative PCR (qPCR) technique in the presence of SYBR dye. The qPCR could successfully detect DNA amounts representing two S. sclerotiorum ascospores and was not sensitive to a variety of tested fungi such as Botrytis cinerea, Alternaria brassicae, Fusarium solani. In contrast to the amount of rainfall, a direct relationship was found between ascospore numbers and the incidence of potato white mold from 2011 to 2014. [ABSTRACT FROM AUTHOR]

This study was conducted during the cropping seasons of 2016 and 2017 to evaluate inhibitory effect of Coniothyrium minitans as well as three isolates of Trichoderma viz. Trichoderma ceramicum, T. atroviride and T. viridescens together with reduced rates of iprodione against Sclerotinia sclerotiorum. The results showed that in both years, inhibitory effect of each biocontrol agents together with reduced application of iprodione at 80% and 60% the recommended rate was statistically on par with application of the fungicide at 100% the factory advised rate. [ABSTRACT FROM AUTHOR]