scholarly journals A Study of Fungal Diseases Occurring on Stored Tomatoes of Balkhu Agriculture and Vegetable Market, Nepal

2020 ◽  
Vol 31 (1) ◽  
pp. 107-122
Author(s):  
Bimala Shakya ◽  
Hari Prasad Aryal

Tomatoes are one of the most widely produced and consumed vegetable in Nepal. Fungal pathogens deteriorate the quality and quantity of tomato and cause health hazards to the consumers as well as economic loss to the traders. This study was carried out to identify some fungal diseases associated with post-harvest deterioration of stored tomato fruits in Balkhu Agriculture and vegetable Market of Kathmandu, Nepal. Collected samples were cultured in Potato Dextrose Agar (PDA) media in complete randomized design. Fifteen species of fungi namely Alternaria alternata, A. solani, Aspergillus niger, Botrytis cinerea, Fulvum fulva, Colletotrichum truncatum, Curvularia spicifera, Fusarium oxysporum, Dipodascus geotrichum, Mucor mucedo, Penicillium chrysogenum, Phytophthora infestans, Boeremia exigua, Pythium aphanidermatum and Rhizopus stolonifer were identified. These were responsible for 14 different diseases of Alternaria fruit rot, Anthracnose, Black mold rot, Botrytis Bunch Rot, Damping off/ fruit rot, Drechslera mold, Fusarium rot, Mucor rot, Penicillum rot, Boeremia blight, Phytophthora rot, Rhizopus rot, Russet, and, Sour rot. The presence of these fungi and corresponding rot diseases on stored tomato indicates the need for management of fungi, farm sanitation and improved market in order to prevent field-to-storage transmission of pathogen.

Author(s):  
Muhammad Nazir Uddin ◽  
Nasrullah ◽  
Muddasir Khan

Onion is an important vegetable and a source of income for formers in District Swat, Pakistan. However, the crop is attacked by several pathogens i.e. fungi, bacteria, viruses, and nematodes. Therefore, a study was carried out for the estimation of fungal diseases of onion crop in district Swat. Within this study, about 50 samples of diseased onion crop were collected from 17 different regions of District Swat. The most prevalent fungal borne onion diseases were black mold (38%), onion rust (32%), Blue Mold Rot (10%) and seedling. Fungal species were consistently isolated from all infected samples. In which Aspergillus was isolated from 82% samples, Puccinia Alli was from 70%, Alternaria porri from 52%, Fusarium spp from 42% Penicillium spp from 40%, Peronospora destructor from 35%, Pyhtaium from 23% and Rhizoctonia solani from 18% of samples. These fungal species consistently isolated and cultured from diseased onion plants of different fields in Swat. Keywords: Onion crop, Fungal diseases, Aspergillus.


2009 ◽  
Vol 62 ◽  
pp. 402-402
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright

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


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Jianghua Chen ◽  
Zihang Zhu ◽  
Yanping Fu ◽  
Jiasen Cheng ◽  
Jiatao Xie ◽  
...  

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China.


2008 ◽  
Vol 20 (1) ◽  
pp. 62 ◽  
Author(s):  
M. JALLI ◽  
P. LAITINEN ◽  
S. LATVALA

Fungal plant pathogens causing cereal diseases in Finland have been studied by a literature survey, and a field survey of cereal leaf spot diseases conducted in 2009. Fifty-seven cereal fungal diseases have been identified in Finland. The first available references on different cereal fungal pathogens were published in 1868 and the most recent reports are on the emergence of Ramularia collo-cygni and Fusarium langsethiae in 2001. The incidence of cereal leaf spot diseases has increased during the last 40 years. Based on the field survey done in 2009 in Finland, Pyrenophora teres was present in 86%, Cochliobolus sativus in 90% and Rhynchosporium secalis in 52% of the investigated barley fields. Mycosphaerella graminicola was identified for the first time in Finnish spring wheat fields, being present in 6% of the studied fields. Stagonospora nodorum was present in 98% and Pyrenophora tritici-repentis in 94% of spring wheat fields. Oat fields had the fewest fungal diseases. Pyrenophora chaetomioides was present in 63% and Cochliobolus sativus in 25% of the oat fields studied.;


2021 ◽  
Vol 38 (1) ◽  
pp. 20-37
Author(s):  
Yohana Patricia Anama ◽  
Ricardo Díaz ◽  
David Esteban Duarte-Alvarado ◽  
Tulio Cesar Lagos-Burbano

Fusarium oxysporum is one of the most limiting fungal pathogens of lulo crop. To determine its pathogenicity, this work morphologically and pathogenically characterized F. oxysporum isolates from different lulo-growing municipalities of the Department of Nariño. Twenty isolates were evaluated through a completely randomized design with two factors and three replicates per treatment, including a control. The first factor corresponded to 20 isolates of F. oxysporum and the second to 10 lulo genotypes. The morphological characterization involved determining growth rate (GR), color (CO), mycelial type (MT), medium coloration (Mc), shape (Sh), size (S), number (N) of macroconidial (Ma) and microconidial (Mi) septa, presence of chlamydospores (PC), and chlamydospore shape (CS). Moreover, the pathogenic characterization was based on the incubation period (IP), absolute growth rate (AGR), disease severity (DS), disease incidence (I), and vascular discoloration (VD). The morphological characterization demonstrated that all isolates corresponded to F. oxysporum. For IP, genotype G1 showed the lowest average at 18 days. For AGR, genotype G2 had the lowest height increase at 0.05 cm.day-1. For DS, genotype G1 reached the highest severity level (level 9) and a disease incidence of 100%. This study provides the first report of the special form of F. oxysporum f. sp. quitoense in Nariño. Solanum hirtum, Solanum sessiliflorum, and Solanum estramonifolium were resistant to the isolates evaluated, demonstrating that wild species should be considered as sources of resistance for breeding programs aiming to obtain resistant commercial genotypes.


Author(s):  
S. Nizamani ◽  
A. A. Khaskheli ◽  
A. M. Jiskani ◽  
S. A. Khaskheli ◽  
A. J. Khaskheli ◽  
...  

Background: The post-harvest tomato fruit rot disease is common threat to the tomato fruit, causing huge economic loss as revealed by (GOP, 2018). The present study was conducted for isolatation and identification of causative agent of tomato fruit rot in order to formulate the proper management stretegies. Methods: Study was conducted in three phases. Phase one included collection of tomato fruit samples from vicinity of Tandojam. In phase two pathogens were isolated from the samples at laboratory, while in the phase three pathogens were identified using standard procedures. Result: The experimental results indicated Alternaria solani as the main cause of post-harvest tomato fruit rot. The symptoms observed were presence of brown to black rot lesions on tomato fruits with distinct rings ranging from small pin-heads to whole surface of fruit. A total of six different fungi viz., Alternaria alternata, Aspergillus niger, Alternaria solani, Geotrichum candidum, Fusarium oxysporum and Rhizopus stolonifer were found to be associated with post harvest tomato rot. Significantly higher infection was recorded for A. solani (53.667%) followed by A. niger (16.333%) and G. candidum (13.00%). The lowest infection percentage was observed for F. oxysporum (2.333%), followed by A. alternata (4.00%) and R. stolonifer (9.00%). A. solani produced aerial mycelium with yellowish to reddish diffusible pigments. A. niger cultures were typically black and colonies were initially whitish to yellow and later became brown to black in colour. G. candidum produced white and nonaerial colonies. F. oxysporum produced circular, aerial mycelium initially white, later changed to light pink. R. stolonifer produced whitish to grey fuzzy colonies.


2021 ◽  
Vol 44 (02) ◽  
Author(s):  
NGUYEN NGOC AN ◽  
HUA HUYNH MINH THAO ◽  
HO NGUYEN HOANG YEN ◽  
NGUYEN THI DIEU HANH ◽  
NGUYEN LE HIEN HOA ◽  
...  

Dragon fruit or pitahaya (Hylocereus spp.) are famous for their nutrient-rich favourable taste, which brings high economic value to subtropical and tropical countries. However, dragon fruit cultivation all over the world is threatened by fungal pathogens and among them, Neoscytalidium dimidiatum has recently been shown to be responsible for stem canker and fruit rot which cause big economic losses. In order to find an environmentally friendly way to control this pathogen, five out of sixty-nine bacterial isolates used in a screening test for antifungal activity were selected. All five strains appeared to be aerobic Gram positive spore forming bacteria suggesting that they all belong to the Bacillus genus. Cell-free culture supernatants of these strains were found to strongly inhibit both fungal spore germination and mycelia growth in vitro for at least 5 days. The strain D19 which possessed the highest antagonistic effect was further identified to be Bacillus amyloliquefaciens, a well-known species shown to have antifungal effect against several other pathogenic fungi. Thus, the results of this study opened a new promising perspective to prevent Neoscytalidium dimidiatum infection during cultivation of dragon fruit.


2003 ◽  
Author(s):  
Richard M. Bostock ◽  
Dov Prusky ◽  
Martin Dickman

Monilinia fructicola causes brown rot blossom blight and fruit rot in stone fruits. Immature fruit are highly resistant to brown rot but can become infected. These infections typically remain superficial and quiescent until they become active upon maturation of the fruit. High levels of chlorogenic acid (CGA) and related compounds occur in the peel of immature fruit but these levels decline during ripening. CGA inhibits cutinase expression, a putative virulence factor, with little or no effect on spore germination or hyphal growth. To better understand the regulation of cutinase expression by fruit phenolics, we examined the effect of CGA, caffeic acid (CA) and related compounds on the redox potential of the growth medium and intracellular glutathione (GSH) levels. The presence of CA in the medium initially lowered the electrochemical redox potential of the medium, increased GSH levels and inhibited cutinase expression. Conidia germinated in the presence of CA, CGA, or GSH produced fewer appressoria and had elongated germ tubes compared to the controls. These results suggest that host redox compounds can regulate fungal infectivity.   In order to genetically manipulate this fungus, a transformation system using Agrobacterium was developed. The binary transformation vector, pPTGFPH, was constructed from the plasmid pCT74, carrying green fluorescent protein (GFP) driven by the ToxA promoter of Pyrenophora tritici-repentis and hygromycin B phosphotransferase (hph) under control of the trpC promoter of from Aspergillus nidulans, and the binary vector pCB403.2, carrying neomycin phosphotransferase (nptII) between the T-DNA borders. Macroconidia of M. fructicola were coincubated with A. tumefaciens strain LBA 4404(pPTGFPH) on media containing acetosyringone for two days. Hygromycin- and G418-resistant M. fructicola transformants were selected while inhibiting A. tumefaciens with cefotaxime. Transformants expressing GFP fluoresced brightly, and were formed with high efficiency and frequency of T-DNA integration frequency. The use of these transformants for in situ studies on stone fruit tissues is discussed.


2021 ◽  
Vol 5 (2) ◽  
pp. 063-064
Author(s):  
Selim Rasha E ◽  
Khalil Mohamed S

Strobilurin is a group of natural products and their synthetic analogs have been widely used to control and prevent fungal diseases. Strobilurins were firstly isolated in 1977 from the mycelium of Strobilurus tenacellus, a saprobic Basidiomycete fungus causing wood-rotting on forest trees. This group of pesticides was designed to manage fungal pathogens classes such as Ascomycetes, Basidiomycetes, and Oomycetes. Also, Strobilurin commercialized included derivatives such as are azoxystrobin, kresoxim-methyl, picoxystrobin, fluoxastrobin, oryzastrobin, dimoxystrobin, pyraclostrobin and trifloxystrobin. This group is a part of the larger group of QoI inhibitors, which act to inhibit the respiratory chain at the level of Complex III. Strobilurins group control an unusually wide array of fungal diseases, included water molds, downy mildews, powdery mildews, leaf spotting and rusts. This group are used on cereals, field crops, fruits, tree nuts, vegetables, turfgrasses and ornamentals. Also, Strobilurins found to enhance the plant growth in some cases.


2016 ◽  
Vol 52 ◽  
pp. 19-27 ◽  
Author(s):  
Edward Ntui Okey ◽  
Patrick Ishoro Akwaji ◽  
Juliet Bassey Akpan ◽  
Etim Johnson Umana ◽  
Glory Akpan Bassey

The inhibitory properties of the ethanolic and methanolic leaf extracts of Vernoniaamygdalina and Colaacuminata on the fungal pathogens isolated from infected tomato fruits were investigated. The pathogens were Fusariummoniliformes and Rhizopusstolonifer. Various concentrations of the extracts ranging from 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100% were separately added to PDA media. The fungal pathogens were separately inoculated into the media and incubated for seven days. Antifungal effects of these extracts on the mycelia growth of the pathogens were significant at P<0.05 for all treatments at higher concentrations. At 10-50% concentration, ethanolic and methanolic extracts of Vernoniaamygdalina and Cola acuminata had no significant effect on the mycelia growth of Fusariummoniliformes and Rhizopusstolonifer after seven days observation period. At 60-100% concentrations, the two pathogens were completely inhibited by ethanolic extracts of Vernoniaamygdalina and Cola acuminata. Methanolic extracts of Vernoniaamygdalina and Cola acuminata inhibited completely Fusariummoniliformes and Rhizopusstolonifer at 80-100% concentrations. The in vitro inhibitory effects of these extracts at higher concentrations indicated that they can be used for the control of tomato fruit rot. It may be necessary to use them in prolonging the shelf-life of fresh tomato fruit and some other fruits.


Sign in / Sign up

Export Citation Format

Share Document