Web Blight Research Articles

Survey on Web Blight of Mungbean [Vigna radiata (L.) Wilczek.] Caused by Rhizoctonia solani Kuhn in Major Growing District of Rajasthan

Web blight (Rhizoctonia solani Kühn) is one of the major diseases of mungbean. The mode of infection is soil-borne, seed borne and air-borne. Random survey was conducted during the kharif season (2022) to study the intensity of web blight in mungbean growing areas of Rajasthan which include Jaipur, Ajmer, Nagaur, Sikar and Tonk. The result showed that the disease intensity ranged from 15.70% to 31.04%. An average disease intensity of 23.57 % was recorded in the surveyed districts. The maximum intensity of web blight disease was recorded in Ajmer District (31.04%).

In vivo Evaluation of Botanicals and Bio-Agents against Web Blight (Rhizoctonia solani) of Mungbean (Vigna radiata)

Web blight, caused by the fungus Rhizoctonia solani, poses a significant threat to mungbean (Vigna radiata) production, leading to yield losses and economic repercussions. This study investigates the antifungal of botanical extracts and bio-agents in managing web blight in mungbean crops. A series of controlled experiments were conducted to assess the antifungal properties of selected botanicals and the biocontrol potential of specific microbial agents. Various extracts, including botanicals and bio-agents have been found effective for management of web blight of mungbean caused by R. solani. The present investigation was carried out on disease management through use of botanicals and bio-agents. The minimum disease incidence and maximum disease control was obtained in Garlic followed by Ginger, Neem, Onion, Tulsi, Clerodendron, Sadabahar, at 10% concentrations at 50 days after sowing in pot sown crop, Each treatments differed significantly from each other.

Screening and evaluation of bacterial endophytes of cowpea [Vigna unguiculata (L.) Walp.] for plant growth promotion and biocontrol potential

Cowpea [Vigna unguiculata (L.) Walp], is a popular leguminous vegetable crop grown in the wetland fallows of Kerala, India. Web blight caused by Rhizoctonia solani has turned out to be a problem in cowpeas, leading to substantial yield loss. We isolated 22 endophytic bacteria from fodder cowpea var. Aiswarya and 16 from bush cowpea var. Bhagyalakshmi, and evaluated their plant growth promotion ability and potential for web blight pathogen suppression. Initially, the isolates were screened in vitro for their plant growth promotional traits and antagonism against R. solani. The potential isolates were identified as Bacillus subtilis, B. amyloliquefaciens and B. velezensis through 16S rDNA cataloguing. Plant growth-promoting traits like the production of IAA (Indole acetic acid), ammonia, phosphorus, and siderophore by the promising isolates were also investigated. B. amyloliquefaciens CBSE5 recorded the highest IAA (3.54 microgram/mL) and siderophore production. B. velezensis CBRE5 showed the highest ammonia (177.29 micro moles/mL) production and phosphate solubilization. In the in vivo assay, seed biopriming along with foliar application on 20 and 40 days after sowing, of a consortium of B. amyloliquefaciens CBSE5 and B. velezensis CBRE5 recorded maximum values for all growth parameters viz. shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, pod yield and number of pods per plant. The present study reports for the first time the use of endophytic Bacillus spp. isolated from cowpeas as plant growth-promoting bacteria, with biocontrol potential against the web blight pathogen R. solani.

Diseases prevalent in Kharif crops grown in Barmer district of Rajasthan, India

In the Kharif season, pearl millet (Pennisetum glaucum) is the predominant crop of the Barmer district followed by cluster bean (Cyamopsis tetragonoloba) and moth bean (Vigna aconitifolia). Sesame (Sesamum indicum) and green gram (Vigna radiata) are other important Kharif oilseed and pulse crops, respectively. A survey was conducted to determine the status of major diseases of Kharif crops grown in the Barmer district of the Marwar region of Rajasthan, India. Five blocks and three villages in each block were surveyed through a random field survey method during the collection of diseased samples every Sunday for the practical classes of agricultural students of the College of Agriculture, Baytu; in August and September 2023. Per cent disease incidence was recorded on randomly selected plants in a particular field of selected location. The incidence of diseases was observed based on typical field symptoms and later the association was confirmed through microscopic examinations in the laboratory. In survey, yellow mosaic (virus), leaf crinkle/ curl (virus), bacterial leaf spot/ blight (Xanthomonas phaseoli) of green gram;green ear/ downy mildew (Sclerospora graminicola), rust (Puccinia substriata) and blast (Pyricularia grisea) of pearl millet; Phytophthora stem blight (Phytophthora parasitica var. sesame) and phyllody (Phytoplasma) of sesame; yellow mosaic (virus)and bacterial leaf spot/ blight (Xanthomonas axonopodis pv. cyamopsidis) of cluster beanwere recorded with >50% incidence. However; charcoal rot (Macrophomina phaseolina), web blight (Rhizoctonia solani), Cercospora leaf spot (Cercospora canescens) and anthracnose (Colletotrichum lindemuthianum) of green gram; Alternaria blight/ leaf spot (Alternaria sesame) of sesame,sorghum rust (Puccinia purpurea) and Alternaria blight/ leaf spot (Alternaria cyamopsidis) of cluster beanwere noticed with 10 to 50% incidence.

In vitro Evaluation of Botanicals, Bio-agents and Fungicides against Rhizoctonia solani Causing Web Blight Disease of Mungbean

In vitro Evaluation of Botanicals, Bio-agents and Fungicides against Rhizoctonia solani Causing Web Blight Disease of Mungbean

Screening of Mungbean [Vigna radiata (L.) Wilczek] Genotypes against Web Blight Caused by (Rhizoctonia solani Kühn) for Disease Resistance

Mungbean [Vigna radiata (L.) Wilczek] is the important source of proteins, minerals, and vitamins of the predominantly vegetarian Indian diet. Web blight caused by Rhizoctonia solani (Kuhn) is one of the most important fungal diseases which appear every year in varying intensity and causes heavy reduction in yield. The present investigations were carried out at the Student’s Instructional Farm (S.I.F.) A.N.D.U.A. &T., Kumarganj, Ayodhya to test the resistance of 100 genotypes against Rhizoctonia solani Kühn under natural conditions (In vivo).Genotypes were placed in different grades according to the rating scale which is based on disease severity. Out of total test entries nine genotypes viz., DGGV-2, OUM11-5, RMG1030, IPM9901-8, DGG1, SML10-82, MH2-15, LGG450 and CGG945 were found free from infection, twelve genotypes viz., RMG-975, CGG-973, AKM -8802, IPM -02-3, MH-4, Pusa -0672, AKM-4, CO-5 Check, Bbara S. check, Asha, BPMR 145 and IPM 02-14 were recorded highly resistant, twenty four genotypes were noticed susceptible and only nine genotypes were found highly susceptible.

Association of cropping practices, cropping areas, and foliar diseases of common bean (Phaseolus vulgaris L.) in Ethiopia

Common bean production is being constrained by a number of diseases. The survey was carried out to prioritize common bean diseases and their associations with cropping areas and cultural practices. A stratified random assessment on 114 farmer's fields was conducted in Ethiopia's four common bean producing zones (Metekel, Sidama, Wolaita, and Halaba). Data are collected randomly on disease severity, incidence levels, and agronomic practices. The results revealed that eleven foliar diseases were found to affect common bean production. Among them, the maximum disease severity and distribution was scored for angular leaf spot (Pseudocercospora griseola) (mean disease severity of 17.8%) and bean anthracnose (Colletotrichum lindemuthianum) (10.9%) followed by floury leaf spot (Mycovellosiella phaseoli), ascochyta blight (Ascochyta phaseolorum Sacc), and web blight (Thanatephorus cucumeris). A multiple correspondence analysis was conducted, and revealed a significant association between the diseases, cropping areas and cultural practices. Optimal crop density was found to be associated with lower bean anthracnose and mosaic virus severities, while being liked to high levels of angular leaf spot and frog-eye leaf spot. Additionally, optimum sowing dates were associated with low severities of bean anthracnose, angular leaf spot, frog-eye leaf spot, Halo Blight, and mosaic virus. On the other hand, a high weediness level was found to be associated with higher levels of web blight and bean anthracnose. Intercropping and row planting were obtained to reduce angular leaf spot and increase occurance of ascochyta blight compared to monocropping. Furthermore, row planting were found to decrease bean anthracnose, angular leaf spot, and cercospora leaf spot when compared to broadcasting. The application of fertilizer was found to decrease the occurances of bean anthracnose, halo blight, floury leaf spot, and angular leaf spot. Therefore, efforts should focus on the optimization and integration of cultural practices for managing disease and producing common bean sustainably.

Forecasting models for forewarning Anthracnose and web blight of mung bean (Vigna radiata) under Tarai zone of Uttarakhand

Mung bean (Vigna radiata L.) is attacked by numerous diseases of which anthracnose and web blight are predominant in Tarai Zone of Uttarakhand. Anthracnose and web blight of mung bean are caused by Colletotrichum lindemuthianum and Rhizoctonia solani, respectively. Their occurrence and development are highly influenced by weather conditions during the cropping season. Based on epidemiological data recorded at Pantnagar for two consecutive years (2019 and 2020), disease predictive models were developed using stepwise multiple regression. The result from the recorded data revealed that rainfall, T(min), rainy days, and morning relative humidity were statistically significant. Whereas, the T(max), evening relative humidity, and bright sunshine hours were statistically non-significant. Significant weather parameters were employed to develop suitable web blight and anthracnose prediction models for commonly grown varieties of mung bean. The prediction models were further validated using the web blight and anthracnose incidence data collected in mung bean varieties in 2021. The root mean square error values varied between 0.0002 – 0.0011, which shows that the models are accurate and acceptable.

Adaptation and Disease Resistance of Elite Tropical Black Bean Lines

Background: Chiapas and Veracruz are the main producing states in the lowlands of southeastern Mexico, with a total harvested volume of 90,146 t of grain in 2020, in a joint planting area of 151,037 ha. However, the cultivation of this legume is subject to a series of biological, climatic and edaphic problems, which make the average yields notoriously low. The objective of this study was to identify high-yielding black bean lines, resistant to diseases and with better adaptation than three commercial cultivars currently used in both entities. Methods: During 2019 and 2020, in seven environments of Veracruz and Chiapas, 11 lines and the cultivars Negro Jamapa, Negro Medellín and Verdín were evaluated. An analysis of variance of the variables was performed by each environment and combined analysis of the incidence of BGYMV and grain yield. Result: Jamapa Plus/XRAV-187-3-4-4 was the most productive line, with an average yield of 1,542 kg ha-1, statistically similar to that of Jamapa Plus/XRAV-187-3-1-2 and higher than that of the rest of the genotypes. Both lines showed resistance to web blight and rust and low incidence of BGYMV, diseases that significantly reduced grain yield. Jamapa Plus/XRAV-187-3-1-2 showed stability throughout the evaluation environments.

Endophytic Bacillus spp. suppress Rhizoctonia solani web blight of bush cowpea

Web blight disease caused by Rhizoctonia solani Kühn, has become a serious problem in cowpea (Vigna unguiculata (L.) Walp.) leading to drastic yield loss in the tropics. Endophytic bacteria isolated from healthy fodder cowpea and bush cowpea were evaluated for their effects on web blight disease incidence. The isolates were first screened for their in vitro antagonism against R. solani. Out of the 38 isolates screened, three promising isolates were selected and identified as Bacillus subtilis, B. amyloliquefaciens and B. velezensis. Under in vivo conditions, seed biopriming with B. velezensis CBRE5 along with its foliar application twice was found to be the best treatment for the management of web blight of cowpea with the minimum percent disease index of 32%. The present study indicated that endophytic Bacillus spp. isolated from the host plant could be used as potential biocontrol agent against web blight disease of cowpea caused by R. solani. This is the first report on management of any disease of cowpea with endophytic microbes isolated from the host plant.

Artificial Inoculation Technique to Produce Web Blight Disease on Mungbean

Artificial Inoculation Technique to Produce Web Blight Disease on Mungbean

Impact of Web Blight on Photosynthetic Performance of an Elite Common Bean Line in the Western Amazon Region of Colombia

Disease stress caused by plant pathogens impacts the functioning of the photosynthetic apparatus, and the symptoms caused by the degree of severity of the disease can generally be observed in different plant parts. The accurate assessment of plant symptoms can be used as a proxy indicator for managing disease incidence, estimating yield loss, and developing genotypes with disease resistance. The objective of this work was to determine the response of the photosynthetic apparatus to the increased disease severity caused by web blight Thanatephorus cucumeris (Frank) Donk on the common bean (Phaseolus vulgaris L.) leaves under acidic soil and the humid tropical conditions of the Colombian Amazon. Differences in chlorophyll fluorescence parameters, including Fv/Fm, Y(II), Y(NPQ), Y(NO), ETR, qP, and qN in leaves with different levels of severity of web blight in an elite line (BFS 10) of common bean were evaluated under field conditions. A significant effect of web blight on the photosynthetic apparatus was found. A reduction of up to 50% of energy use dedicated to the photosynthetic machinery was observed, even at the severity scale score of 2 (5% surface incidence). The results from this study indicate that the use of fluorescence imaging not only allows for the quantifying of the impact of web blight on photosynthetic performance, but also for detecting the incidence of disease earlier, before severe symptoms occur on the leaves.

Biological management of cowpea web blight incited by Rhizoctonia solani

Among the diseases of cowpea, web blight caused by Rhizoctonia solani Kuhn is the most serious soil borne disease which causes severe yield loss. A field trial was conducted during kharif 2016 to manage web blight disease of cowpea at ARS field of SKRAU, Bikaner. Combination of T. harzianum plus B. subtilis used as seed treatment (5 + 5 g/kg) and soil application (5+5 kg/ha) proved to be most effective against web blight incited by R. solani in field conditions and provided maximum disease control (79.5%). Seed emergence, plant survival, fresh and dry weight, root and shoot lengths and grain yield was higher and per cent cowpea plant mortality was lower in treatment T. harzianum plus B. subtilis used in combination as seed treatment (5 + 5 g/kg) and soil application (5 + 5 kg/ha). The bioagents used in the present investigation could be therefore, used as a part of integrated disease management (IDM) strategy for web blight of cowpea in areas where the disease is reported to cause substantial yield losses.

Rhizoctonia spp. causing damping-off, root rot and web blight on coriander in Brazil

Rhizoctonia spp. causing damping-off, root rot and web blight on coriander in Brazil

Characterization of fungal pathogens and germplasm screening for disease resistance in the main production area of the common bean in Argentina.

The common bean (Phaseolus vulgaris L.) is the most important grain legume in the human diet, mainly in Africa and Latin America. Argentina is one of the five major producers of the common bean in the world, and the main cultivation areas are concentrated in the northwestern provinces of this country. Crop production of the common bean is often affected by biotic factors like some endemic fungal diseases, which exert a major economic impact on the region. The most important fungal diseases affecting the common bean in Argentina are white mold caused by Sclerotinia sclerotiorum, angular leaf spot caused by Pseudocercospora griseola, web blight and root rot caused by Rhizoctonia solani, which can cause production losses of up to 100% in the region. At the present, the most effective strategy for controlling these diseases is the use of genetic resistance. In this sense, population study and characterization of fungal pathogens are essential for developing cultivars with durable resistance. In this review we report diversity studies carried out on these three fungal pathogens affecting the common bean in northwestern Argentina, analyzing more than 200 isolates by means of molecular, morphological and pathogenic approaches. Also, the screening of physiological resistance in several common bean commercial lines and wild native germplasm is reviewed. This review contributes to the development of sustainable management strategies and cultural practices in bean production aimed to minimize yield losses due to fungal diseases in the common bean.

Rhizoctonia Aerial Blight of Soybean, its Prevalence and Epidemiology: A Review

Soybean [Glycine max (L.) Merrill] is high value oilseed crop grown throughout the world as well as in few soybean growing pockets in India. The hot and humid weather conditions during the soybean cropping season favours the attack by various fungal, bacterial and viral diseases, thereby lowering the crop productivity. Rhizoctonia aerial blight or web blight disease, caused by Rhizoctonia solani is considered one of the most economically important disease of soybean in India. It causes yields losses ranging from 35-60% which might reach a devastating level of 80% under favourable environmental conditions. In India, the disease has been reported from most of the soybean growing states of Uttrakhand, Rajasthan, Sikkim, Haryana, Punjab, Uttar Pradesh, Bihar, Madhya Pradesh, Chhattisgarh and Assam. Epidemiological studies prove to be very important in managing the disease as the disease severity highly depends on the weather variables prevailing in the growing season. The present review has attempted to compile findings on this devastating disease of soybean crops, its prevalence in the country, epidemiological studies and strategies on integrated disease management.

DISEASES OF MOTH BEAN [VIGNA ACONITIFOLIA (JACQ.) MARECHAL

Pulses are obtained from leguminous plants that have many bioactive components and good nutritional value, being rich in protein, vitamins, and abundant macro- and micronutrients and thus contribute to global food security. Moth bean is compatible with the climatic conditions of Rajasthan because it is a drought-resistant crop though it is affected by many pathogenic microorganisms as fungi, bacteria, and viruses. Infection of these microorganisms causes damage to plants which results in loss of productivity. In the current context, a review on fungal, bacterial, and viral diseases of moth bean has been dealt with. The major diseases of moth bean reported are leaf blight, leaf spots, seedling stem and root rot, pod rot, web blight, common bacterial blight, and mung bean yellow mosaic virus (MYMV) causing yield loss.

Seasonal Variation in the Population of Whitefly (Bemisia tabaci) and Incidence of Web Blight in Black Gram, Vigna mungo (L.) Hepper under Sub-mountainous Region of Punjab

The increasing incidence of whitefly ( ) and web blight disease ( Kuhn) cause huge yield loses in Bemisia tabaci Rhizoctonia solani black gram. Keeping this in view, a study was conducted at research farm of Dr. D.R. Bhumbla Regional Research Station, Ballowal Saunkhri, (SBS Nagar), Punjab during 2019 and 2020 to ascertain the impact of different meteorological parameters on the occurrence and kharif development of whitefly population and web blight disease on black gram. The whitefly attained peak population of 12.88 and 16.56 whiteflies/leaf in 38 SMW during 2019 and 2020 respectively. Among all weather parameters, maximum temperature showed significant th positive correlation with whitefly population during 2019 (r=0.71) and 2020 (r=0.73) respectively. In case of web blight, maximum disease severity and PDI (54.7 and 65.9 %) were in 34 SMW in 2019 while in 2020, maximum disease severity (42.0%) was in 38 SMW. A positive th thcorrelation of disease severity and per cent disease index was found with maximum temperature and relative humidity (morning) during both crop seasons. The results will help in formulation of insect-pest and disease monitoring system followed by sustainable integrated pest and disease management programme.

Temporal progress of web blight in three common bean genotypes on the central coast of Ecuador

Web blight caused by Rhizoctonia solani Kuhn is one of the main common beans (Phaseolus vulgaris L.) diseases of the Ecuadorian central coast. Thus, the present study aimed to evaluate the progress of web blight incidence using nonlinear models in promising genotypes SER 03 and SER 08, using the commercial cultivar INIAP 473 as a control. This study was carried out between the 2010 and 2012 seasons in Quevedo, Ecuador. Epidemiological parameters such as initial disease (y0), disease progress rate (r), final incidence and the area under the disease progress curve were estimated using the Exponential, Logistic, and Gompertz models. In general, progress curves, epidemiological parameters and other evaluated plant health variables were lower in the INIAP 473 cultivar than the other genotypes in 2011 and 2012, especially in the last season when higher y0 and r were observed in the commercial cultivar. It seems that soil and seeds inoculum and temperature play an important role in standard bean crop disease progress. While the response of genotypes and each location conditions influenced the epidemic modeling, the Logistic model better described the web blight progress under these conditions.

Breeding for resistance and integrated management of web blight in common bean

AbstractCommon bean (Phaseolus vulgaris L.) production in the humid tropics may increase if less predictable rainfall becomes a serious seed yield constraint in traditional areas of production. The successful production of common bean will require the effective management of common bean diseases favored by hot and humid conditions. Web blight (WB), caused by Thanatephorus cucumeris (Frank) Donk, is a serious disease of common bean in the humid tropics causing significant losses in both seed yield and seed quality. At present, only moderate levels of WB resistance have been identified. Leaf and seed damage and leaf lesion size are criteria that have been successfully used to screen common bean genotypes for WB resistance in the greenhouse and in the field. Pedigree selection has been successfully used to develop cultivars having moderate levels of resistance. Recurrent selection has been used to broaden the genetic base and to produce progeny having higher levels of WB resistance. Sources of resistance from secondary gene pools should be used to combine resistance genes from diverse sources. Common bean cultivars with earlier maturity, deep tap roots, and terminal drought tolerance may be desirable traits for farmers who plant later in the wet season to avoid WB. Seed production during the dry season using irrigation would help to reduce infection of the seed and transmission of the WB pathogen. Minimum tillage techniques are useful to help to reduce the spread of the disease. Biological control may contribute to the management of WB and complement genetic resistance.