scholarly journals Southern Sclerotium Root Rot Caused byAthelia rolfsiion Table Beet in New York

2019 ◽  
Vol 20 (1) ◽  
pp. 4-6
Author(s):  
Sarah J. Pethybridge ◽  
Sandeep Sharma ◽  
Alex Silva ◽  
Carol Bowden ◽  
Sean Murphy ◽  
...  

Southern Sclerotium root rot caused by Athelia rolfsii (syn. Sclerotium rolfsii) is a damaging soilborne disease of field and specialty crops. In 2015, 2016, and 2017, wilted plants, root rot, and decay in six table beet (Beta vulgaris spp. vulgaris) fields across New York were observed. In these outbreaks, losses ranged between 5 and 25%. White mycelial mats and golden brown sclerotia (1 to 2 mm diameter) were observed on diseased plants and decayed roots. The objective of this study was to identify the fungus associated with these symptoms and assess pathogenicity in table beet.

Author(s):  
Shivannegowda Mahadevakumar ◽  
Yelandur Somaraju Deepika ◽  
Kandikere Ramaiah Sridhar ◽  
Kestur Nagaraj Amruthesh ◽  
Nanjaiah Lakshmidevi

Plant Disease ◽  
2021 ◽  
Author(s):  
Qianwen Liu ◽  
Hanyang Wang ◽  
Wenpeng Song ◽  
Jiuming Yu ◽  
Lu Huang ◽  
...  

Kiwifruits (Actinidia ssp.), known as “King of vitamin C”, have been wildly cultivated. In August 2020, about 15% of A. deliciosa (cv. Xuxiang) and A. macrosperma (rootstock) plants displayed symptoms typical of root rot at a farm in Hefei (117°25′E, 31°86′N), Anhui Province of China (Fig.1 a-b). Symptoms first appeared at the root and stem junction which were covered by cottony white mycelium during warm and humid summer. Then, the infected tissues were rotted, and subsequently the whole plant withered. Tan to brown sclerotia were observed on the basal stem epidermis and soil surface surrounding the stem (Fig.1 c-d). Infected plant tissues and sclerotia were collected for isolating the fungal pathogen. The samples were surface sterilized in 70% alcohol for 30 s, followed by 2% sodium hypochlorite for 3 min, washed five times with sterile double-distilled water (ddH2O), dried, placed on potato dextrose agar, and incubated at 25 °C in the dark. In total, twelve fungal isolates were obtained. The mycelia of all the isolates were white with a fluffy appearance (Fig.1 e). Sclerotia formed after 7 days were initially white (Fig.1 f) and gradually turned to dark brown (Fig.1 g) measuring 0.67 to 2.03 mm in diameter (mean = 1.367 ± 0.16 mm; n = 30). Hyphae were hyaline, septate. Some cells possessed multiple nuclei (Fig.1 h) and clamp connections (Fig.1 i). No spores were observed. For species-level identification, ITS1/ITS4 and EF1-983F/EF1-2218R primers were used to amplify the internal transcribed spacer regions (ITS) and translation elongation factor-1 alpha regions (TEF-1α), respectively (White et al. 1990; Rehner & Buckley 2005). Based on ITS and TEF-1α sequence analyses, all 12 isolates were categorized into two groups, group one including isolates NC-1 and NC-6~10 and group two containing NC-2~5 and NC-11~12. The length of ITS sequences for NC-1 (MW311079) was 684bp and 99% to 100% similar to Athelia rolfsii (MN610007.1, MN258360.1). Similarly, ITS sequences for NC-2 (MW311080) were 99% to 100% similar to A. rolfsii (MH858139.1; MN872304.1). Also, TEF-1α sequences of NC-1 (MW322687) and NC-2 (MW322688) were 96% to 99% similar to sequences of A. rolfsii (MN702794.1, GU187681.1, MN702789.1). Based on morphology and phylogenetic analyses (Fig.1 j&k), the isolates NC-1 and NC-2 were identified as Athelia rolfsii (anamorph Sclerotium rolfsii) (Mordue. 1974; Punja. 1985). To fulfill Koch’s postulates, ten sclerotia of NC-1 were incorporated into the soil near stems of healthy Xuxiang plants (Fig.2 a). Similar treatments were also used for plants of A. macrosperma or A. arguta (Fig.2 g&m). Each control group had the same number of plants (n=3) for inoculating with ddH2O. The plants were kept in an incubator with a relative humidity of 80% and temperature of 28°C with 16/8 hours light/dark photoperiod. After twenty days, the pathogen-inoculated plants developed similar symptoms of root rot observed in the field (Fig.2 b-d, h-j, n-o). Similarly, four days after inoculation with sclerotia, leaves developed water-soaked lesions (Fig.2 e, k&p). No significant difference in pathogenicity was observed between NC-1 and NC-2. Non-inoculated control plants remained disease-free (Fig.2 f, l&q). The pathogenicity experiments were repeated three times. The pathogen was re-isolated from infected tissues and sclerotia, and isolates were confirmed as A. rolfsii by the ITS sequences. A. rolfsii has been reported to cause root rot in kiwifruit in the USA (Raabe. 1988). To our knowledge, this is the first report A. rolfsii causing root rot on kiwifruits in China.


Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 849-849 ◽  
Author(s):  
S. T. Koike

In June 2013, a commercial organic planting of Swiss chard (Beta vulgaris subsp. cicla) in Monterey County, CA, showed symptoms of a soilborne disease. Early symptoms consisted of delayed and stunted growth, with wilting of foliage during the warmer times of the day. Initially, a light brown discoloration developed on stems at the soil line. As disease progressed, a dark brown necrosis extended up the main stem and down along the upper portion of the taproot. In advanced cases, the plants collapsed and died. Extensive white cottony mycelium and numerous brown, spherical sclerotia, approximately 1 mm in diameter, developed externally on the lower stem, crown, and adhering adjacent soil. For this particular planting, approximately 10% of the 0.4 ha was lost. Sequentially planted sets of chard placed in other parts of the farm were unaffected. Isolations from necrotic plant tissues, sclerotia, and white mycelium all resulted in recovery of the same white fungus that in culture produced identical sclerotia but no other reproductive structures. Based on white mycelium, sclerotia morphology, and the presence of clamp connections at hyphal septa, the fungus was identified as Sclerotium rolfsii (1). Pathogenicity was tested by growing isolates on potato dextrose agar, drying the resulting sclerotia for 48 h, then burying 5 to 8 sclerotia adjacent to the crowns of healthy Swiss chard plants grown in pots. Three isolates were tested using 24 plants per isolate. Six control plants were inoculated with sterilized sand. All plants were incubated in a greenhouse at 22 to 25°C. After 8 days, inoculated plants began to wilt. By 14 days after inoculation, 100% of the inoculated plants showed symptoms identical to those observed in the field. One half of the plants were used for re-isolations, from which S. rolfsii was recovered from all necrotic crown and stem tissues. The other half of the plants were maintained in the greenhouse; these plants later supported the development of sclerotia. Sand-inoculated control plants did not develop any disease symptoms. The experiment was repeated and the results were the same. To our knowledge, this is the first report of southern blight of Swiss chard in California. Southern blight has not previously been found in this cooler, western part of the county adjacent to the Pacific Ocean; southern blight has been documented on other crops such as pepper, tomato, and chives (3) in the warmer eastern and southern parts of Monterey County. S. rolfsii has been reported on Swiss chard in Louisiana, South Carolina, and Cuba (2). References: (1) K. H. Domsch et al. Compendium of Soil Fungi, 2nd edition. IHW-Verlag, Eching, Germany, 2007. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. Online publication, ARS, USDA. Retrieved July 26, 2013. (3) S. T. Koike et al. Plant Dis. 78:208, 1994.


Author(s):  
Jefferson Bertin Vélez-Olmedo ◽  
Sergio Vélez-Zambrano ◽  
Bianca Samay Angelino Bonfim ◽  
Edisson Cuenca Cuenca ◽  
Susana García ◽  
...  

2013 ◽  
Vol 47 (13) ◽  
pp. 1629-1644 ◽  
Author(s):  
M. Paramasivan ◽  
A. Chandrasekaran ◽  
S. Mohan ◽  
N. Muthukrishnan

2016 ◽  
Vol 106 (10) ◽  
pp. 1170-1176 ◽  
Author(s):  
A. K. Mahoney ◽  
E. M. Babiker ◽  
T. C. Paulitz ◽  
D. See ◽  
P. A. Okubara ◽  
...  

Root rot caused by Rhizoctonia spp. is an economically important soilborne disease of spring-planted wheat in growing regions of the Pacific Northwest (PNW). The main method of controlling the disease currently is through tillage, which deters farmers from adopting the benefits of minimal tillage. Genetic resistance to this disease would provide an economic and environmentally sustainable resource for farmers. In this study, a collection of synthetic-derived genotypes was screened in high-inoculum and low-inoculum field environments. Six genotypes were found to have varying levels of resistance and tolerance to Rhizoctonia root rot. One of the lines, SPBC-3104 (‘Vorobey’), exhibited good tolerance in the field and was crossed to susceptible PNW-adapted ‘Louise’ to examine the inheritance of the trait. A population of 190 BC1-derived recombinant inbred lines was assessed in two field green bridge environments and in soils artificially infested with Rhizoctonia solani AG8. Genotyping by sequencing and composite interval mapping identified three quantitative trait loci (QTL) controlling tolerance. Beneficial alleles of all three QTL were contributed by the synthetic-derived genotype SPCB-3104.


2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Manzoor R. Khan ◽  
Zaki A. Siddiqui

AbstractEffects of Pseudomonas putida and Bacillus subtilis alone, and in combinations for the management of Meloidogyne incognita, Pectobacterium betavasculorum, and Rhizoctonia solani disease complex of beetroot (Beta vulgaris L.), were studied. Application of P. putida or B. subtilis to plants with M. incognita or P. betavasculorum or R. solani singly or in combinations caused a significant increase in plant growth parameters and the activities of defense enzymes. A significant increase in chlorophyll fluorescence attributes, viz., Fv/Fm, ɸPSII, qP, NPQ, and ETR were recorded in plants treated with P. putida or B. subtilis over pathogen-inoculated plants. Inoculation of P. putida results in a higher reduction in galling and nematode multiplication than B. subtilis. Maximum reduction in nematode multiplication and galling occurred when a mixture of P. putida and B. subtilis was used. Soft rot and root rot indices were 3 when Pectobacterium betavasculorum and Rhizoctonia solani were inoculated alone. The disease indices were rated 5 when these pathogens and M. incognita were inoculated in combinations. Inoculation of P. putida/B. subtilis with P. betavasculorum or R. solani reduced soft rot and root rot indices to 2 out of 3, while the use of P. putida + B. subtilis reduced indices to 1. Disease indices were reduced to 2–3 out of 5, when P. putida + B. subtilis were used to plants inoculated with two or three pathogens. The principal component analysis showed significant correlations among the various studied attributes. Two principal components explained a total of 86.1 and 93.4% of the overall data variability. Therefore, the use of P. putida together with B. subtilis had the potential for successful management of disease complex of beetroot.


1981 ◽  
Vol 10 (2) ◽  
pp. 9-16 ◽  
Author(s):  
Gene L. Swackhamer

The eleven state area of Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont comprises the Northeast agricultural area. According to the latest farm number estimates in 1980, there are over 159,000 farms in the Northeast with the largest number of farms concentrated in Pennsylvania, New York and Maryland, respectively. Given the large number of farms and the diverse topography of the region, farmers in the Northeast produce a wide variety of agricultural commodities. In 1980, farm cash receipts in the Northeast were estimated at $8.2 billion with livestock and products accounting for about two thirds of the total and crops (including specialty crops) accounting for the balance. In terms of cash receipts, Pennsylvania is the largest agricultural production state in the Northeast followed by New York and Maryland.


Sign in / Sign up

Export Citation Format

Share Document