Effects of Water Temperature, Inoculum Concentration and Age, and Sanitizer Presence on Infection of Ceratocystis fimbriata, Causal Agent of Black Rot in Sweetpotato

Plant Disease ◽  
2020 ◽  
Author(s):  
Madison Stahr ◽  
Lina Quesada-Ocampo
Keyword(s):  
Water Temperature ◽  
Disease Incidence ◽  
Postharvest Disease ◽  
Black Rot ◽  
Storage Roots ◽  
Ceratocystis Fimbriata ◽  
Inoculum Concentration ◽  
Inoculum Age ◽  
Negative Controls ◽  
Water Treatments

Black rot, caused by Ceratocystis fimbriata, is a devastating postharvest disease of sweetpotato that recently re-emerged in 2014. Although the disease is known to develop in storage and during export to overseas markets, little is known as to how pathogen dispersal occurs. This study was designed to investigate dump tank water as a means of dispersal through four different types of water treatments: inoculum concentration (0, 5, 5 × 101, 5 × 102, and 5 × 103 spores/ml), inoculum age (0, 24, 48, 96, and 144 h), water temperature (10, 23, 35, and 45˚C), and presence of a water sanitizer (DryTec, Sanidate, FruitGard, and Selectrocide). Wounded and non-wounded sweetpotato storage roots were soaked in each water treatment for 20-min, stored at 29˚C for a 14-day period, and rated for disease incidence every other day. Disease was observed in sweetpotato storage roots in all water treatments tested, except in the negative controls. Disease incidence decreased with both inoculum concentration and inoculum age, yet values of 16.26% and up to 50% were observed for roots exposed to 5 spores/ml and 144 h water treatments, respectively. Sanitizer products that contained a form of chlorine as the active ingredient significantly reduced disease incidence in storage roots when compared to control roots and roots exposed to a hydrogen-peroxide based product. Finally, no significant differences in final incidence were detected in wounded sweetpotato storage roots exposed to water treatments of any temperature, but a significant reduction in disease progression was observed in the 45˚C treatment. These findings indicate that if packing line dump tanks are improperly managed, they can aid C. fimbriata dispersal through the build-up of inoculum as infected roots are unknowingly washed after storage. Chlorine-based sanitizers can reduce infection when applied after root washing and not in the presence of high organic matter typically found in dump tanks.

Sweetpotato root development influences susceptibility to black rot caused by the fungal pathogen Ceratocystis fimbriata

2021 ◽  
Author(s):  
Camilo Humberto Parada Rojas ◽  
Kenneth Pecota ◽  
Christie Almeyda ◽  
G. Craig Yencho ◽  
Lina Quesada-Ocampo
Keyword(s):  
Root Development ◽  
Disease Incidence ◽  
Black Rot ◽  
Wild Relative ◽  
Storage Root ◽  
Storage Roots ◽  
Ceratocystis Fimbriata ◽  
Breeding Lines ◽  
Below Ground ◽  
Storage Root Development

Black rot of sweetpotato caused by Ceratocystis fimbriata, is an important reemerging disease threatening sweetpotato production in the United States. This study assessed disease susceptibility of the storage root surface, storage root cambium, and slips (vine cuttings) of 48 sweetpotato cultivars, advanced breeding lines, and wild relative accessions. We also characterized the effect of storage root development on susceptibility to C. fimbriata. None of the cultivars examined at the storage root level were resistant, with most cultivars exhibiting similar levels of susceptibility. In storage roots, Jewel and Covington were the least susceptible and significantly different from White Bonita, the most susceptible cultivar. In the slip, significant differences in disease incidence were observed for above and below ground plant structures among cultivars, advanced breeding lines, and wild relative accessions. Burgundy and Ipomoea littoralis displayed less below ground disease incidence as compared to NASPOT 8, Sunnyside and LSU-417, the most susceptible cultivars. Correlation of black rot susceptibility between storage roots and slips was not significant, suggesting that slip assays are not useful to predict resistance in storage roots. Immature, early developing storage roots were comparatively more susceptible than older, fully developed storage roots. The high significant correlation between storage root cross-section area and cross-sectional lesion ratio suggests the presence of an unfavorable environment for C. fimbriata as the storage root develops. Incorporating applications of effective fungicides at transplanting and during early storage root development when sweetpotato tissues are most susceptible to black rot infection may improve disease management efforts.

scholarly journals Effects of Temperature, Concentration, Age, and Algaecides on Phytophthora capsici Zoospore Infectivity

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 54-60 ◽  
Author(s):  
L. L. Granke ◽  
M. K. Hausbeck
Keyword(s):  
Water Temperature ◽  
Irrigation Water ◽  
Phytophthora Capsici ◽  
Growing Season ◽  
Laboratory Studies ◽  
Inoculum Concentration ◽  
Pickling Cucumbers ◽  
Effects Of Temperature ◽  
Water Treatments ◽  
Zoospore Suspension

Controlled laboratory studies were undertaken to determine the effects of water temperature (2, 9, 12, 19, 22, and 32°C), inoculum concentration (1 × 102, 1 × 103, 5 × 103, 1 × 104, 2 × 104, and 4 × 104 zoospores/ml), and zoospore suspension age (0, 1, 3, and 5 days old) on infection of pickling cucumbers (Cucumis sativus) by Phytophthora capsici. Zoospore motility and mortality in response to commercial algaecides were also investigated. Cucumbers became infected at all temperatures tested, except 2°C, and the highest infection incidence was observed for cucumbers incubated in suspensions held at ≥19°C. Fewer fruit (<40% at ≥19°C, 0% at ≤12°C) became infected when water contained 1 × 102 zoospores/ml. Almost 100% of fruit were infected when water contained ≥5 × 103 zoospores/ml at temperatures ≥12°C. While the incidence of fruit infection declined with the zoospore suspension age, infection still occurred when 5-day-old suspensions were used. Commercial algaecides inhibited zoospore motility and caused significant zoospore mortality in laboratory assays, and show promise for treatment of infested irrigation water. Avoidance of infested irrigation water throughout the growing season is warranted until effective and economically acceptable water treatments are developed for field use.

scholarly journals Assessing the Role of Temperature, Inoculum Density, and Wounding on Disease Progression of the Fungal Pathogen Ceratocystis fimbriata Causing Black Rot in Sweetpotato

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 930-937 ◽  
Author(s):  
M. Stahr ◽  
L. M. Quesada-Ocampo
Keyword(s):  
Disease Management ◽  
Disease Incidence ◽  
Management Strategies ◽  
The United States ◽  
Storage Conditions ◽  
Inoculum Density ◽  
Separate Experiment ◽  
Black Rot ◽  
Disease Development ◽  
Ceratocystis Fimbriata

In 2014, Ceratocystis fimbriata, causal agent of black rot in sweetpotato, reemerged and inflicted large financial losses on growers in the United States. Black rot continues to damage sweetpotatoes and has become a priority to the industry since then. In contrast, little is known about the biology of C. fimbriata and the epidemiology of sweetpotato black rot. In this study, effects of environmental factors such as inoculum density, RH, and temperature on sweetpotato black rot were determined. Cured sweetpotatoes were wounded with a toothpick to simulate puncture wounds, inoculated with different spore suspensions (inoculum density) (104, 105, or 106 spores/ml), and incubated under different RH (85.53, 94.09, or 97.01%) and temperature (13, 18, 23, 29, or 35°C) for 21 days. In a separate experiment, five root wounding types (cuts, punctures, abrasions, end breaks, and macerating bruises) were compared. All wounded roots were subsequently soaked in a 103 spores/ml suspension and incubated at 100% RH and 23°C for 21 days. This study found 29 and 23°C to be the optimal temperature for black rot disease development and sporulation, respectively. No pathogen growth was observed at 13 and 35°C. Increased inoculum density significantly (P < 0.0001) increased disease incidence, but increasing RH had an effect only on sporulation area. All wound types resulted in increased disease incidence and sporulation as early as 7 days postinoculation. Our results highlight the importance of characterizing factors that affect disease development for achieving successful disease management strategies. Findings from this study will be used to improve disease management for sweetpotato black rot by suggesting tighter regulation of curing and storage conditions and better postharvest handling of sweetpotato roots to avoid unnecessary wounding.

Transgenic sweet potato expressing thionin from barley gives resistance to black rot disease caused by Ceratocystis fimbriata in leaves and storage roots

2012 ◽  
Vol 31 (6) ◽  
pp. 987-997 ◽  
Author(s):  
Nobuhiko Muramoto ◽  
Tomoko Tanaka ◽  
Takashi Shimamura ◽  
Norihiro Mitsukawa ◽  
Etsuko Hori ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Black Rot ◽  
Storage Roots ◽  
Ceratocystis Fimbriata ◽  
Rot Disease ◽  
And Storage

scholarly journals Sweetpotato cultivar susceptibility to infection by Ceratocystis fimbriata

2011 ◽  
Vol 64 ◽  
pp. 1-6 ◽  
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright ◽  
C.M. Triggs
Keyword(s):  
Crop Production ◽  
Ipomoea Batatas ◽  
Lateral Roots ◽  
The United States ◽  
Black Rot ◽  
Storage Roots ◽  
Ceratocystis Fimbriata ◽  
Susceptibility To Infection ◽  
Cultivar Susceptibility ◽  
Japanese Cultivar

The fungus Ceratocystis fimbriata causes a disease of the sweetpotato (Ipomoea batatas) plant commonly known as black rot This study evaluated sweetpotato cultivar susceptibility to C fimbriata infection During crop production infection of sweetpotato storage roots may take place by transmission from contaminated transplants but generally the pathogen is introduced directly through openings in the periderm These openings may take the form of damaged secondary lateral roots lenticels or wounds In a laboratorybased bioassay storage roots were punctured then pointinoculated with the pathogen Following incubation under warm humid conditions the dimensions of black rot lesions were compared The predominant New Zealand cultivar Owairaka Red was demonstrably less susceptible to C fimbriata than the Japanese cultivar Beniazuma but significantly more susceptible than Beauregard from the United States of America (P

Diseases of the kumara crop

2009 ◽  
Vol 62 ◽  
pp. 402-402
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright
Keyword(s):  
Fungal Pathogens ◽  
Ipomoea Batatas ◽  
Mechanical Damage ◽  
Soft Rot ◽  
Economic Loss ◽  
Root Surface ◽  
Black Rot ◽  
Rhizopus Stolonifer ◽  
Ceratocystis Fimbriata ◽  
Pink Rot

The predominant diseases of the commercial kumara (Ipomoea batatas) or sweetpotato crop are caused by fungal pathogens The field disease pink rot results from infection by the fungus Sclerotinia sclerotiorum Lesions form on vines but may spread down stems to the roots The widespread nature of this disease in sweetpotato appears peculiar to New Zealand Scurf is a disease caused by Monilochaetes infuscans which occurs in the field but may proliferate amongst stored roots The disease causes a superficial discolouration of the root surface which is mainly cosmetic but can also increase root water loss in storage Infection by Ceratocystis fimbriata produces a disease known as black rot The disease can be transmitted amongst plants at propagation but is particularly rampant amongst roots in storage This disease is readily transmitted and can cause severe economic loss Fusarium oxysporum causes surface rots in stored roots characterised by light to dark brown lesions that tend to be firm dry and superficial The lesions may be circular and centred on wounds caused by insects or mechanical damage at harvest Soft rot caused by Rhizopus stolonifer generally occurs in roots after they are washed and prepared for the market Fungal infection occurs through wounds or bruised tissue producing distinctive tufts of white fungal strands and black spores

Sweet-Potato Black Rot (Ceratocystis fimbriata, Ell. & Hals.)

1891 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
B. D. Halsted ◽  
D. G. Fairchild
Keyword(s):  
Sweet Potato ◽  
Black Rot ◽  
Ceratocystis Fimbriata

scholarly journals First Report of Anthracnose of Papaya (Carica papaya L.) Caused by Colletotrichum siamense in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yujie Zhang ◽  
Wenxiu Sun ◽  
Ping Ning ◽  
Tangxun Guo ◽  
SuiPing Huang ◽  
...  
Keyword(s):  
Carica Papaya ◽  
Disease Incidence ◽  
Aerial Mycelium ◽  
Postharvest Disease ◽  
Distilled Water ◽  
First Report ◽  
Surface Samples ◽  
Initial Symptoms ◽  
Colletotrichum Siamense ◽  
Pathogenicity Tests

Papaya (Carica papaya L.) is a rosaceous plant widely grown in China, which is economically important. Anthracnose caused by Colletotrichum sp. is an important postharvest disease, which severely affects the quality of papaya fruits (Liu et al., 2019). During April 2020, some mature papaya fruits with typical anthracnose symptoms were observed in Fusui, Nanning, Guangxi, China with an average of 30% disease incidence (DI) and over 60% DI in some orchards. Initial symptoms of these papayas appeared as watery lesions, which turned dark brown, sunken, with a conidial mass appearing on the lesions under humid and warm conditions. The disease severity varied among fruits, with some showing tiny light brown spots, and some ripe fruits presenting brownish, rounded, necrotic and depressed lesions over part of their surface. Samples from two papaya plantations (107.54°E, 22.38°N) were collected, and brought to the laboratory. Symptomatic diseased tissues were cut into 5 × 5 mm pieces, surface sterilized with 2% (v/v) sodium hypochlorite for 1 minute, and rinsed three times with sterilized water. The pieces were then placed on potato dextrose agar (PDA). After incubation at 25°C in the dark for one week, colonies with uniform morphology were obtained. The aerial mycelium on PDA was white on top side, and concentric rings of salmon acervuli on the underside. A gelatinous layer of spores was observed on part of PDA plates after 7 days at 28°C. The conidia were elliptical, aseptate and hyaline (Zhang et al., 2020). The length and width of 60 conidia were measured for each of the two representative isolates, MG2-1 and MG3-1, and these averaged 13.10 × 5.11 μm and 14.45 × 5.95 μm. DNA was extracted from mycelia of these two isolates with the DNA secure Plant Kit (TIANGEN, Biotech, China). The internal transcribed spacer (ITS), partial actin (ACT), calmodulin (CAL), chitin synthase (CHS), β-tubulin 2 (TUB2) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) regions were amplified by PCR and sequenced. The sequences were deposited into GenBank with accessions MT904003, MT904004, and MT898650 to MT898659. BLASTN analyses against the GenBank database showed that they all had over 99% identity to the type strain of Colletotrichum siamense isolate ICMP 18642 (GenBank accession numbers JX010278, GQ856775, JX009709, GQ856730, JX010410, JX010019) (Weir et al., 2012). A phylogenetic tree based on the combined ITS, ACT, CAL, CHS, TUB2 and GAPDH sequences using the Neighbor-joining algorithm also showed that the isolates were C. siamense. Pathogenicity tests were conducted on 24 mature, healthy and surface-sterilized papaya fruits. On 12 papaya fruits, three well separated wounded sites were made for inoculation, and for each wounded site, six adjacent pinhole wounds were made in a 5-mm-diameter circular area using a sterilized needle. A 10 µl aliquot of 1 × 106 conidia/ml suspension of each of the isolates (MG2-1 and MG3-1) was inoculated into each wound. For each isolate, there were six replicate fruits. The control fruits were inoculated with sterile distilled water. The same inoculation was applied to 12 non-wound papaya fruits. Fruits were then placed in boxes which were first washed with 75% alcohol and lined with autoclaved filter paper moistened with sterilized distilled water to maintain high humidity. The boxes were then sealed and incubated at 28°C. After 10 days, all the inoculated fruits showed symptoms, while the fruits that were mock inoculated were without symptoms. Koch's postulates were fulfilled by re-isolation of C. siamense from diseased fruits. To our knowledge, this is the first report of C. siamense causing anthracnose of papaya in China. This finding will enable better control of anthracnose disease caused by C. siamense on papaya.

scholarly journals Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Aline Machado de Castro ◽  
Mariana Martins Pereira Teixeira ◽  
Daniele Fernandes Carvalho ◽  
Denise Maria Guimarães Freire ◽  
Leda dos Reis Castilho
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Desirability Function ◽  
Aspergillus Awamori ◽  
Inoculum Concentration ◽  
Simultaneous Production ◽  
Inoculum Age ◽  
Multiresponse Optimization ◽  
Propagation Medium ◽  
Babassu Cake

This work aimed at investigating the simultaneous production of amylases and proteases by solid-state fermentation (SSF) of babassu cake using Aspergillus awamori IOC-3914. By means of experimental design techniques and the desirability function, optimum inoculum conditions (C/N ratio of propagation medium, inoculum age, and concentration of inoculum added to SSF medium) for the production of both groups of enzymes were found to be 25.8, 28.4 h, and 9.1 mg g−1, respectively. Significant influence of both initial C/N ratio and inoculum concentration was observed. Optimum amylolytic activities predicted by this multiresponse analysis were validated by independent experiments, thus indicating the efficacy of this approach.

scholarly journals First Report of Cylindrocladium Black Rot of Peanut Caused by Cylindrocladium parasiticum (Teleomorph Calonectria ilicicola) in Jiangxi Province, China

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 586-586 ◽  
Author(s):  
Y. Gai ◽  
Q. Deng ◽  
R. Pan ◽  
X. Chen ◽  
M. Deng
Keyword(s):  
Southern China ◽  
Disease Incidence ◽  
Jiangxi Province ◽  
Black Rot ◽  
Brown Pigment ◽  
Fruiting Bodies ◽  
Calonectria Ilicicola ◽  
Cylindrocladium Parasiticum ◽  
Stem Lesions ◽  
Reddish Orange

In July 2010, a serious disease of peanut (Arachis hypogaea) resembling Cylindrocladium black rot (CBR) was found in Longnan County, Jiangxi Province, China. Symptoms included chlorotic, yellowish and blighted leaves, and wilting of the plants. Taproots and hypocotyls were blackened and rotted. Clusters of reddish orange spherical fruiting bodies appeared in the lesions present on basal stems, pegs, pods, and roots of peanut. Disease incidence reached as much as 50% in some patches of the field. Plants with symptoms were sampled from fields. Microscopic examination revealed that the reddish orange, spherical fruiting bodies were the perithecia and measured 461.6 (337.5 to 609.4) × 395.5 (309.4 to 496.9) μm. With gentle pressure, asci and ascospores were exuded from perithecia. The asci were hyaline, thin walled, and long stalked. Ascospores were hyaline, falcate with one septum, and measured 43.5 (27.3 to 54.5) × 5.6 (4.1 to 6.8) μm with a length/width (L/W) ratio of 7.8 ± 1.3. A fungus with white-to-pale buff border mycelia and yellowish brown pigment was consistently isolated from the edge of basal stem lesions on potato dextrose agar at 25°C. Mycelia grew at temperatures ranging from 8 to 32°C and the optimum was 25 to 26°C. To determine the species, single-conidial isolates of the fungus were cultured on carnation leaf agar for 7 days at 25°C and 12 h of light/dark conditions. Conidia were hyaline, cylindrical with one to three septa (mostly three septa), and measured 49.3 (27.3 to 70.9) × 5.9 (4.1 to 6.8) μm with L/W ratio of 8.4 ± 1.6. Vesicles were globose and measured 5.5 to 10.9 μm in diameter. The fungus was identified as Cylindrocladium parasiticum (teleomorph Calonectria ilicicola) (1,2). A PCR assay was conducted on one representative isolate (JXLN32) by analyzing multilocus sequences of the TUB2 (coding β-tubulin protein), ACT (coding actin), and CaM gene (coding calmodulin protein) and were amplified and sequenced using the primers reported by Crous et al. (3). Sequences of the studied DNA regions were submitted to GenBank (Accession Nos. TUB2: JF429649; ACT: JQ070809; and CaM: JQ070808). BLAST searches with the existing sequences in GenBank showed that there was 99 to 100% identity with the existing sequences of C. ilicicola (GenBank Accession Nos. TUB2: AY725643; ACT: GQ280446; and CaM: GQ267402). To complete Koch's postulates, inoculum was prepared by mixing the microsclerotia (MS) suspension of the isolate (JXLN32) with soil at a proportion of 10 MS per g of soil. Ten replicate plastic pots containing five peanut seeds (cv. Yueyou 7) each were planted and placed in a glasshouse at 25 ± 2°C. The same number of peanut seeds was used as an uninoculated control. Typical basal stem and roots rot symptoms of CBR were observed in 2 months and C. parasiticum was reisolated from these inoculated diseased plants. No symptoms were detected on the control plants. To our knowledge, this is the first finding of Cylindrocladium black rot in Jiangxi Province, which is the main peanut-producing area in China. The disease has been previously reported in Guangdong Province in southern China but is not known elsewhere (4). Because of its ability to spread through seed and soil and its destructive potential, this pathogen may pose a serious threat to peanut production in China. References: (1) D. K. Bell and E. K. Sobers. Phytopathology 56:1361, 1966. (2) P. W. Crous et al. Mycol. Res. 97:889, 1993. (3) P. W. Crous et al. Stud. Mycol. 50:415, 2004. (4) R. Pan et al. Plant Pathol. 58:1176, 2009.

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