Potato crop is the fourth main food crop in the world and it will certainly feed a big part of the global population in the next years. The economical outlets for this crop are great; however, numerous diseases either soil- or air-borne can cause huge losses in the production. Worldwide, about 40 soil-borne diseases affect potato and cause severe damages especially on tubers, the economically most important part of the plant. The occurrence and development of soil-borne diseases depend on very diverse factors affecting either the pathogen or the plant. Favorable conditions for potato diseases development are frequently the same as the conditions needed for potato growth: temperature between 10°C and 25°C, high humidity, medium pH, etc. Adapted cultural practices such as a rotation longer than 4 years, appropriate fertilization and water management, an adapted delay between haulm killing and harvest, and dry and cool conditions for tuber storage are good ways to control potato diseases. In most cases, potato pathogens develop specific survival forms, dissemination ways and host penetration methods. The genetic variability of the pathogens implies the use of adapted diagnostic and control methods. Decision support systems developed to predict yield losses allow choosing good control methods such as the use of healthy seeds, adapted pesticides, cultural practices, and biological control agents for each potato disease. The complexity of the interactions between a pathogen and its host, influenced by biotic and abiotic factors of the environment, make the control of the diseases often very difficult. However, deep knowledge of pathosystems allows setting up integrated pest management systems allowing the production of healthy and good quality potatoes.

/pdf/potato-soil-borne-diseases-a-review-cb2rrubef2.pdf

Potato soil-borne diseases. A review

Okra (Abelmoschus esculentus (L.) Moench) crop is being affected by several fungal, bacterial, viral and nematode induced diseases. However, leaf spot, caused by Alternaria chlamydospora has been common occurrence, causing quantitative as well as qualitative losses in okra. Therefore, in present study, four fungicides (two systemic, one each contact and combi-fungicide), bioagent T. viride and Neem oil were integrated by giving three srays at an interval of 15 days, for management of Alternaria leaf spot of okra (Hyb. NOH-1684). The experiment was planned and conducted in RBD with ten treatments replicated thrice, at the Department of Plant Pathology, College of Agriculture, Latur, VNMKV, Parbhani (MS), during Kharif, 2017. The results revealed that all the treatments significantly influenced leaf spot disease incidence, intensity, fruit parameters, fruit yield and incremental cost: benefit ratio (ICBR), over untreated control. Based on average disease intensity and its reduction over untreated control, the most effective treatment found was Carbendazim 25% + Mancozeb 50% WS @ 0.25%, with least average disease intensity (15.51%) and its highest reduction (50.09%), followed by Hexaconazole 5% EC @ 0.1% + Neem oil @ 0.2% (16.87% and 45.72%, respectively), Hexaconazole 5% EC @ 0.1% (17.45% and 43.85%, respectively) and Mancozeb 75% WP @ 0.25% + Neem oil @ 0.2% (17.58% and 43.43%, respectively). Rest of the treatments were found also effective. All the treatments also improved fruit parameters and fruit yield. Based on ICBR, the most economical and effective treatment found was Carbendazim 25% + Mancozeb 50% WS @ 0.25%, and Hexaconazole 5% EC @ 0.1% + Neem oil @ 0.2% (2.70), followed by Hexaconazole 5% EC @ 0.1% (2.60); whereas, it was least with Neem oil @ 0.2% (1.79).

https://www.chemijournal.com/archives/2019/vol7issue5/PartAS/7-5-394-707.pdf

Integrated management of okra leaf spot caused by Alternaria chlamydospora

Groundnut (Arachis hypogaea L.) is an important leguminous edible oilseed crop. Stem and pod rot of groundnut caused by Sclerotium rolfsii is an economically important disease of groundnut. Looking to the high disease incidence in Kharif season and economic damage due to stem and pod rot some basic and applied research studies were carried out. The initial symptoms expressed yellowing and wilting of branches. Under high humidity and moist soil surface this fungus produced white mycelium around affected plants at or near the soil surface. Abandant sclerotia were produced on the mycelial mat on the affected plant parts adjacent to soil surface. The sclerotia were initially white later turned brown to dark brown when mature. Shredded stems and peg tissue were noticed as typical symptom. The affected branches or whole plant died. Peg and pods were also affected and seeds of severely affected pods were discolored. The fungal pathogen was isolated from diseased plant on PDA. The Koch’s postulates were successfully proved on groundnut cv. GG-20 and GG-7. Thirty isolates of pathogen collected from different locations of Saurashtra region and IARI, New Delhi differed in morphological characters viz. mycelial growth, colony colour, mycelial appearance, sclerotial colour, size, shape, weight and arrangement. Basidiospores were not observed in any of the isolates when tested on C-PDA medium. During the survey stem rot incidence ranged from 2 to 40 per cent in 76 locations of Saurashtra. The highest incidence was observed in Keshod and Vanthali talukas of Junagadh district followed by Amreli, Rajkot, Jamnagar, Bhavnagar and Porbandar districts. The avoidable pod yield loss due to stem and pod rot was 40.89 per cent which was equivalent to loss of 856 kg/ha or Rs. 17120 /ha. The plant species viz. castor, sorghum, wheat, cumin, bottle gourd, and bitter gourd remained disease free from S. rolfsii infection during host ranged study. Two weed plants viz. Sickle pod (Cassia tora L.) and beggar (Desmodium triquetrum L.) were recorded as new hosts of S. rolfsii in the present investigation. Total phenol content decreased in infected tissues of highly susceptible and susceptible varieties of groundnut as compared to healthy tissues. However phenol content was higher in infected tissues of moderately resistant varieties of groundnut than healthy. Total sugars and oxalic acid were higher in infected stem tissues of groundnut as compared to healthy tissues. Maximum oxalic acid was recorded in the isolate CTRI2754 (1.60mg/5ml filtrate) followed by Keshod isolate (1.44mg/5ml). Maximum dry mycelium weight (896.67mg) was recorded in the Dhoraji isolate. The cellulase and PG activity in the culture medium decreased under the growth inhibition of test pathogen due to Trichoderma isolates. The activity of -1,3-glucanase was recorded maximum in T. harzianum-4J v/s S. rolfsii (4.21 μM glucose/min/ml CF). The -1,3glucanase activity in the culture increased with increase in growth inhibition of the pathogen by respective antagonists. Chitinase activity also increased during antagonism and its highest activity was recorded in the culture medium of T. viride (Bang.) v/s S. rolfsii followed by T. viride (Local) v/s S. rolfsii. Laboratory screening of fungicides, insecticides, weedicides and fertilizers were carried out against the pathogen. Among the fungicides, vitavax, propiconazole, hexaconazole, mancozeb and carbendazim 50 wp + mancozeb 75 wp, (1:2 manual mixture) exhibited cent per cent growth inhibition at all the concentrations. Similarly the insecticides viz. chlorphyriphos and endosulfan also inhibited cent per cent growth at 750, 1000 and 1500 ppm. The herbicides viz. quizalofop-ethyl and metsulfuran were also highly effective and showed cent per cent growth inhibition of S. rolfsii at all concentrations tried. Complete growth inhibition was also recorded in IFFCO-NPK at 4000 ppm concentration. Sclerotial formation was hampered in CAN, NPK 12:32:16 (IFFCO), SSP and DAP at 3000 and 4000 ppm concentrations. Ten selective chemicals were tested for germination of sclerotia of S. rolfsii under in vitro conditions and cent per cent sclerotial germination inhibition was reported in hexaconazole and vitavax. Cent per cent growth inhibition of all the isolates of S. rolfsii was found in propiconazole (500 ppm) and tebuconazole (500 ppm) and vitavax power (2000 ppm), while sensitivity of mancozeb (2500 ppm) varied against different isolates. Ten selective isolates of Trichoderma were tested against the S. rolfsii under in vitro condition and highest inhibition of S. rolfsii (77.41%) was observed in the presence of T. harzianum–4J followed by T. viride (68.52%)) and T. harzianum-2J (64.44%). Looking to the overgrowing of Trichoderma on S. rolfsii, T. viride (Local) and T. viride (Bang.) completely overgrew the pathogen and categorized into R1 as per modified Bell’s scale. Trichoderma viride (Local) was also tested against 23 isolates of the pathogen. The growth inhibition of the isolates ranged from 44.44 to 74.93 per cent. Different seed treatments were evaluated under field condition for stem and pod rot management. Minimum disease incidence was recorded in the seed treatment of Trichoderma harzianum 10.00g/kg seed followed by vitavax power (vitavax + thiram) 3.0 g/kg seed and tebuconazole 1.25 g/kg seed. Efficacy of different soil amendments with Trichoderma harzianum on disease incidence was conducted in field conditions for two Kharif seasons. Minimum stem and pod rot incidence was recorded in the treatment of caster cake @500 kg/ha amended with T. harzianum@1.5kg/ha followed by FYM @ 500kg/ha amended with T. harzianum @ 1.5kg/ha. An experiment on integrated management of stem and pod rot of groundnut was conducted under field condition. Highest pod yield (2176 kg/ha) and minimum disease incidence (23.09%) was recorded in preemergence spraying of fluchloraline @1.5kg a.i./ha + seed treatment with vitavax power (vitavax + thiram) 3.0 gm/kg seed + furrow application of T. harzianum @1.5 kg/ha mixed in 300 kg FYM at sowing time + three sprayings of hexaconazole (0.005%) at 35, 55 and 75 days after sowing. None of the varieties was resistant against stem and pod rot disease, when 14 groundnut cultivars screened under artificially inoculated micro plots. Two varieties viz. GG-11 and GG-13 were found moderately resistant, eight varieties viz. J-11, GG-4, GG-6, JL-24, TG-26, TAG-24, BAU-13 and ICGV-86564 were susceptible and rest four varieties viz. GG-2, GG-5, GG-7 and GG-20 were highly susceptible. Under natural conditions three groundnut lines viz. JB-113, JB-1140 and JB-1155 were moderately resistant to S. rolfsii. ACKNOWLEDGEMENT I feel great pleasure in expressing my deep sense of gratitude to my Major Advisor, Dr. K. B. Jadeja, Professor and Head, Department of Plant Pathology, College of Agriculture, Junagadh Agricultural University, Junagadh for his unique guidance, enlightening suggestions, close supervision, keen interest, constructive criticism, constant encouragement and cordial discussion during the entire period of my study and careful examination of this manuscript. I am fortunate and extremely grateful to the members of my advisory committee, Dr. M. N. Kapadiya. Professor and Head, Department of Entomology, JAU, Junagadh, Dr. I. U. Dhruj, Associate Director of Research, JAU, Junagadh and Dr. S. V. Patel, Professor, Department of Biochemistry, JAU, Junagadh for their constant attention and valuable suggestions during the course of this investigation. I express my thankfulness to Hon. Vice-Chancellor, Director of Research and P. G. Dean and Director of Students Welfare, Junagadh Agricultural University, Junagadh for providing facilities for earning Ph. D. degree as an in-service candidate. I am sincerely thankful to respected Dr. P. G. Butani, Principal College of Agriculture, JAU, Junagadh for providing necessary facilities during course of studies. I feel much obliged to Dr. R. L. Savaliya, Dr. A. M. Parakhiya, and Dr. R. R. Khandar, Ex. Professor & Head, Department of Plant Pathology, JAU, Junagadh for providing laboratory facilities during course of investigation. I am also thankful to Research Scientist, Oilseeds Research Station, JAU, Junagadh for providing seeds of groundnut varieties/ lines for research work. It is my pleasure, immense thanks to Dr. J. P. Borisagar, Principal, Mahila College, Savarkundla for cultivated to me upto this level. I am thankful to Dr. L. F. Akbari, Assistant Research Scientist, Department of Plant Pathology, JAU, Junagadh for his constant technical and morale support during study. I owe my profound thanks to Dr. P. V. Patel, Dr. N. G. Mayani, Dr. V. V. Rajani, Dr. B. K. Chovatiya, Dr. P. K. Patel, Shri K. K. Chheladiya, Shri U. M. Vyas, Shri K. V. Sureja and to all staff members of the Department of Plant Pathology, JAU, Junagadh for their generous help extended to me. My special thanks to Dr. H. P. Gajera and U. K. Kandoliya, from Department of Biochemistry, JAU, Junagadh for constant help throughout biochemical study. Ms Jyoti Amipara, Miss Janki Kayada, Shri K. N. Savaliya, Shri A. D. Kalola and Shri D. M. Pathak for their kind cooperation during my laboratory study. I extent my heartfelt thanks to staff members of ' C ' branch of principal office, examination branch of registrar office and central library for their cooperation during my study. I would like to express my cordial thanks to my senior friends Shri D. P. Vekariya, B. E. (Civil), Shri D. P. Rakholiya, Shri V. N. Kundaliya, Dr. H. L. Dhaduk, Dr. R. K. Mathukia and Dr. M. F. Acharya for their generous help during my study work. I wish to express my deepest gratitude and heartfelt respect to my beloved parents and younger brother. I fully appreciate and commendable patience, personal sacrifice, for their encouragement and co-operation of my wife Smt. Nita, my sons Nisarg and Krunal during the period of my study. At last million of than

INTEGRATED MANAGEMENT OF STEM AND POD ROT OF GROUNDNUT CAUSED BY Sclerotium rolfsii Sacc.

Aspergillus flavus and Fusarium moniliforme, the two post-harvest pathogens of papaya caused high physical (lesion diameter, tissue decay, discoloration and % decay) and biochemical (total sugars, carotenoids, ascorbic acid and total titratable acidity) decay in papaya fruits. Fungi were able to colonize wounded fruits only and presence of host extract accelerated pathogenicity. Pathogens had wide host range and infected 12 other fruit species to varying degrees except Citrus chinesis. Maximum growth/sporulation of pathogens was seen on PDA/CD A, at pH range 4–6, with temperature optima being 30–35°C and a humidity range of 60–100%.

Pathogenic and Cultural properties of Post-harvest pathogens of Papaya

The visual quality of fresh potatoes, Solanum tuberosum, became a dominant criterion and a significative economical issue in potato market. According the vegetative reproduction of this species, requirements for visual quality are also needed for potato seed tubers. As an organ for reserve and propagation, the tuber grows underground and is in contact with soil-borne microorganisms, making it potentially exposed to blemishes, for the majority of which the origin is still unclear.The objective of this work is to make an inventory of those tuber blemishes, to characterize them and determine their causes. After the establishment of consensual nomenclature and classification of the blemishes, two hypotheses were formulated: (1) blemishes are due to pathogenic attacks and/or (2) they result from a response of the plants to environmental stresses. The assessment of the first hypothesis allowed identifying a wide diversity of microorganisms living on the blemished tuber surface. Their pathogenicity was tested by several biological assays that allowed producing blemishes on progeny tubers and fulfilling the Koch's postulates for the fungus Rhizoctonia solani causing sclerotia. For many other blemishes no clear relationship was established between a microorganism and a blemish. A study of the microbial structure of the geocaulosphere of tubers blemished or not, showed that bacterial and fungal communities adopted different dynamics during the growing season and according to the sanitary status of the seed tuber, but no causality link could have been drawn. On the other hand, an increase of R. solani population around blemished tubers was observed. The diversity of strains of R. solani originating from France and from Europe and associated to the blemished tubers was characterized. The phylogenetic relationships between the strains were independent of the geographical origin and of the host cultivar, thus the existence of frequent genetic events and genetic mixing between the populations of R. solani was suggested. Concerning the potential implication of different abiotic factors, a survey conducted with farmers showed the implication of soil pH, some cultural practices, including the choice of the susceptible cultivars and meteorological conditions on the occurrence of some blemishes. This work made clear the blemish nomenclature, confirmed the implication of R. solani in the occurrence of some blemishes and suggested new hypotheses concerning the occurrence of blemishes as a plant response to a stressful environment. Thus, a path was opened toward the resolution of the issue asked by all the potato community, responsible for the marketing of a mass consumption fresh product and answering to market requirements related to visual and culinary qualities and to environmental friendly modes of production.

https://tel.archives-ouvertes.fr/tel-00572491/document

Origins of the blemishes of potato tubers : from the soil microbiology to the pedoclimatic environment

Role of host nutrition and varieties on the development of stem rot of potato

The inhibitory effects of five botanical oils (Neem, Citronella, Pine, Clove and Garlic) at 0.05%, 0.1% and 0.15% concentrations along with sole application of solvent Xylene were tested under in vitro condition. Four isolates (A1, A2, A3 and A4) of Alternaria solani were collected from different potato growing areas of West Bengal, India. Significant antifungal activities of these five botanical oils against four isolates of A. solani were noticed. Garlic (0.15%) inhibited the maximum mycelial growth of A1 (90.3%). Spore germination was also inhibited due to application of garlic (0.15%) in case of all the isolates of A. solani. Out of five botanical oils, garlic (0.15%) exhibited maximum inhibition of mycelial growth and spore germination over control including sole application of solvent, xylene. Field studies also reveal that foliar sprays of garlic oil (0.15%) not only suppressed the Alternaria leaf blight infection but also enhanced the total tuber yield. Hence, botanical oils should be used as non hazardous natural fungicides in controlling plant pathogenic fungi.

Antifungal Activity of Some Botanical Oils Against Alternaria solani, Causing Leaf Blight of Potato

The kinetics of accumulation of chlorophyll, total so luble sugar and starch, was studied in four potato cultivars, when infected with Phytophthora infestans. Maximum chlorophyll content was found in Kufri Badshah followed by Kufri Jyoti, Kufri Ashoka and Kufri Chandramukhi at 50 DAP. Chlorophyll content was gradually decreased in all the tested cultivars as the blight progressed. But total chlorophyll content in leaves of cultivars Kufri Chandramukhi and KufriAshoka was significantly decreased. Total soluble sugar and starch contents were found significantly reduced as the progress of blight took place. In case of susceptible cultivars i.e, Kufri Ashoka and Kufri Chandramukhi, the rate of depletion of total soluble sugar was significantly higher as compared to tolerant cultivars viz., Kufri Jyoti and Kufri Badshah.

Quantitative estimation of Chlorophyll, Starch and Total soluble sugar in Potato cultivars infected with Phytophthora infestans

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Amitava Basu

Author Tools

Chat about Author

Papers

Role of host nutrition and varieties on the development of stem rot of potato

Antifungal Activity of Some Botanical Oils Against Alternaria solani, Causing Leaf Blight of Potato

Quantitative estimation of Chlorophyll, Starch and Total soluble sugar in Potato cultivars infected with Phytophthora infestans