Controlling Sheath Blight Disease Research Articles

Rice sheath blight disease control by native endophytic Bacillus subtilis from Kuttanad, a Globally Important Agricultural Heritage System

ABSTRACT Kuttanad in India is known as ‘the rice bowl of Kerala’ and renowned for its unique rice cultivation system that is below sea level. However, rice production in this wetland ecosystem is seriously threatened by sheath blight disease caused by the fungus Rhizoctonia solani, which has resulted in a significant decline in grain quality and a 50% loss in yield. In the present study, we isolated two endophytic Bacillus subtilis strains, NIIST B616 and NIIST B627, from the roots of rice plants growing in the Kuttanad region and tested their efficacy in controlling sheath blight disease. We found that rice plants inoculated with a combination of both Bacillus strains and R. solani had a 64.71% lower disease incidence and a 31.02% higher harvest index than plants treated with R. solani alone. An analysis of defence-related enzymes and chemicals revealed that treatment with both isolates together greatly enhanced levels of l-phenylalanine ammonia-lyase (PAL; 2.8 fold), peroxidase (POX; 7.4 fold), polyphenol oxidase (PPO; 4.5 fold), and total phenol (8.5 fold) compared with plants treated solely with R. solani, indicating that these isolates significantly increased plant defence responses through induced systemic resistance (ISR), and this finding was validated through a split-root experiment. More detailed analysis using gas chromatography–tandem mass spectrometry (GC-MS/MS) and liquid chromatography–tandem mass spectrometry (LC-MS/MS) techniques revealed that cyclo-(Pro-Leu) and cyclo-(Pro-Phe) were the major components responsible for the antifungal properties of the two isolates and their capacity to trigger ISR in plants. Thus, the Bacillus strains and their metabolites may be deemed viable alternatives for controlling the prevalence of sheath blight disease in rice plants and augmenting rice production at unique locations such as Kuttanad.

Comparative study between biological and chemical agents for control sheath blight disease of rice

Biological control measures are indispensable to sustain global food security, due to it being economically profitable and environmentally sound. A comparative study was conducted to know the effectiveness of biological control measures compared with contact fungicide. Trichoderma spp. based bio fungicides Bioquick and Biospark were applied as preventive measures and contact fungicide as a curative measure for controlling sheath blight disease in rice varieties BR 71 and IR 24. Biospark and Bioquick were applied before disease development while, contact fungicide was used after the initiation of sheath blight disease. At the early stage of disease development, the effect of Bioquick, Biospark, and fungicide in terms of reducing percent relative lesion height and percent tiller infection are comparable. At 14 DAI and 18 DAI, contact fungicide performed best among the three control measures based on the two parameters. The genotypes of the rice accessions used in the study also appeared to be a factor in disease development, as evidenced by higher horizontal and vertical disease severity in BR71 than in IR24. Between comparison of Bioquick and Biospark in terms of reducing percent relative lesion height, percent tiller infection, and percent disease control, appeared to be higher in Biospark in both varieties. From this study, we can conclude that farmers can use Biospark as a biofungicide to get maximum benefit considering rice yield and ecology. However, its efficacy is slightly lower than chemical fungicides for controlling sheath blight disease of rice.

Effects of fungicides and antagonistic marine-derived fungi on rice seedling promotion and rice sheath blight control

Fourteen fungicides and three marine-derived fungi were tested for their activities in the promotion of rice seedling development and their efficacy in controlling rice sheath blight disease in two rice varieties, RD43 and KMDL105, under greenhouse conditions. The results showed that the rice seeds treated with carbendazim 50%SC and azoxystrobin 25%SC displayed the best promotion of rice growth in root length and shoot height at seven and 14 days in rice var. RD43. Rice seeds from var. KMDL105 treated with thiophanate-methyl 70%WP exhibited significant stimulation of rice seedling growth resulting in the greatest increase in root length and shoot height at seven and 14 days. In pot experiments with rice var. RD43, spraying with triforine 19%EC, propiconazole 25%EC, trifloxystrobin 50%WG, and validamycin 3%SL showed a high level of fungicidal activity in controlling sheath blight disease, with this evidenced by significant suppression of the disease severity by 71–75% and 61–73% at seven and 14 days after inoculation, respectively. The treatment of rice var. KMDL105 with validamycin 3%SL exhibited the best activity in controlling sheath blight disease by reducing disease severity by up to 62% and 64% at seven and 14 days, respectively. The antagonistic marine fungi tested in this study displayed low activity against sheath blight disease and low effects on rice seedling promotion compared to fungicides. Specifically, Trichoderma harzianum KUFA 0689 and T. asperellum KUFA 0677 reduced sheath blight disease severity by 42–46% and 27–37% at seven and 14 days, respectively.

Farmers’ Efficiency in Using Selected Pesticides for Controlling Rice Pests

Farmers’ efficiency in using pesticides depends on using recommended doses. The research was conducted to determine farmers’ efficiency in using selected pesticides for controlling rice pests and explore the contribution of selected characteristics of the farmers to their efficiency in using selected pesticides for controlling rice pests. Data were collected from randomly selected 252 Common Interest Group (CIG) Member rice farmers of three selected unions of three selected upazillas of Brahmanbaria district of Bangladesh with the help of a pre-tested interview schedule during the period from 01 August 2022 to 30 November 2022. Findings revealed that 38.97% farmers were the efficient users of recommended doses and rest 61.03% farmers had lower to moderate efficiency in using pesticides for controlling rice pests. Based on descending order of Standardized Use Efficiency Index, ‘Gola 80 EC for killing rice bug’ ranked 1st followed by ‘Amistar Top 325 SC for controlling sheath blight disease’, and ‘Thiovit 80 WG for controlling leaf scald disease’. Regression analysis indicated that ‘knowledge on pesticides’, ‘rice farming experience’, ‘extension contacts’, ‘attitude towards use of pesticides’, ‘rice farming area’, and ‘pre-cautions for using pesticides’ of the farmers had significant positive contribution to their efficiency in using selected pesticides for controlling rice pests. Agricultural advisory service providing organizations should increasing contact with the farmers having lower farming experience, lower farming area to increase their knowledge for taking necessary pre-cautions and to form favourable attitude towards judicious and efficient use of pesticides.

Genome-wide association mapping for identification of sheath blight resistance loci from wild rice Oryza rufipogon

Sheath blight (ShB) caused by Rhizoctonia solani is one of the serious constraints that hamper global rice production. It causes severe yield loss of up to 69% under favorable environmental conditions. The application of chemical fungicides remains the primary approach for the management of this disease. But, overuse of chemical fungicides causes potential health and environmental risk. The use of host plant resistance is a very effective, economic, and sustainable strategy to control sheath blight disease in rice. In this report, we have evaluated 405 accessions of Oryza rufipogon for four ShB-related traits i.e. lesion height (LH), plant height (PH), relative lesion length (RLH), and disease score (DS) during the years 2015, 2016, and 2017. A total of 44,109 high-quality SNP markers on 301 accessions were employed to identify significant marker-trait associations using a genome-wide association study (GWAS). The GWAS analysis revealed a total of 22 significant SNPs associated with the ShB-related traits distributed on all the rice chromosomes except 10 and 12. Among them, eleven were associated with RLH, seven with PH, and one each with LH and DS. The SNPs on chromosomes 3 and 9 were associated with multiple traits. Furthermore, seven ShB resistance loci were also found to be co-localized with previously reported ShB resistance genes/QTLs. These findings provide valuable information to identify key SNPs associated with ShB resistance. Significantly associated SNPs could be used for introgression of ShB resistance traits into rice cultivars using marker-assisted selection.

Appraise a seed Treatment of Carbendazim 50% WPagainst Sheath Blight Disease of Rice (Oryza sativa L.)

An investigation was carried out to evaluate the efficacy of different dose of Carbendazim 50 % WP as seed treatment on the severity of sheath blight disease and yield contributing characters of rice in the Department of Plant Pathology and the field of University of Agricultural and Horticultural Sciences farm, Shivamogga, Karnataka during the period of 2017 to 2018. Four doses of Carbendazim 50 % WP were evaluated against sheath blight disease at three growth stages (flowering, milking and maturity) and yield attributing features. It was observed that disease severity was gradually increased from flowering stage to maturity stage with the age of the plant and minimum severity gave the maximum yield. Seed treatment of Carbendazim 50% WP @ 4g / kg of seeds or Carbendazim 50% WP @ 3 g/kg of seeds was found to be highly effective in managing sheath blight disease at early stage of crop growth and significantly reduces further spread under field condition by mitigating inoculum at seedling stage which in turn provided higher grain yield and other yield attributing characters. Present study clearly indicated that, Carbendazim 50 % WP was best chemical to control sheath blight disease as seed treatment.

In silico docking of natural compounds from plants against Rhizoctonia solani pectate lyase

Sheath blight disease caused by the fungal pathogen Rhizoctonia solani kuhn is one of the most devastating diseases of rice plant. The disease is controlled mostly by management practices and spraying of fungicides like validamycin. However, the development of pesticide resistance in pathogens has become a cause of concern. In addition, the application of pesticides has adverse environmental effects. Thus, efforts are being made to look for biogenic compounds that could be used for disease control. In this context, the present in silico docking study was carried out to find out the effective biogenic compounds found in plants that could antagonize the pectate lyase enzyme, which is one of the most important plant cell wall degrading enzymes. The compounds selected for the study are active ingredients of plant extracts that have been found to have antagonizing effects against R. solani. The amino acid sequence available for R. solani pectate lyase protein was retrieved from the Uniprot database (entry no. A0A0B7F4Q0) and the three-dimensional model was generated using Swiss-model server. The compounds were docked with the protein using Autodock 4.2 tool. The docking study showed that the binding energies varied between − 2.47 and − 7.79. Validamycin which is used for controlling sheath blight disease had a binding energy of − 2.47. The compounds d-5-Avenasterol (− 7.79), β-sitosterol (− 7.72), gedunin (− 7.59), nimbiol (− 7.16), cycloartenol (− 6.98), stigmasterol (− 6.76), nimbolide (− 6.33) were among the compounds with high binding affinity (low binding energy). Among the amino acids, GLU-217, ARG-326, ASP-228 were found to be predominantly involved in the H-bonding formation. Among the compounds, gedunin, nimbiol, nimbolide met all the criteria for pesticide set by the Tice rule. The compounds gedunin, nimbiol, nimbolide found in the neem plant belong to the chemical class triterpenoid (limonoids), are slightly hydrophilic in nature and soluble in alcohols, ketones and esters. The preliminary findings suggest that these compounds could be used for preparing formulations for controlling the sheath blight disease of rice.

Ekstrak Tanaman Binahong sebagai Pengendali Penyakit Hawar Pelepah Daun Padi

Binahong Extract for Controlling Sheath Blight Disease of Rice PaddySheath blight disease, caused by Rhizoctonia solani, is an important disease that can affect rice production. The disease is commonly controlled using synthetic fungicides. This study was aimed to test the potential of binahong plant (Anredera cordifolia) as botanical fungicide to inhibit the growth of R. solani and the development of blight disease on rice seedlings. The research was conducted in 2 stages, i.e. in vitro and rice seedling testing. In vitro test was carried out on PDA medium containing different concentrations of binahong leaf extract (0.125%, 0.25%, 0.5%, 1%, and 2%). Rice seedling testing was completed by soaking rice seeds in five concentrations of binahong leaf extract followed by inoculation of R. solani. The experiments were arranged in a completely randomized design. The variables observed consist of inhibitory ability of binahong leaf extract, colony morphology of R. solani, and disease incidence. Binahong leaf extract inhibited 35.2% growth of R. solani colonies. Treatment of binahong leaf extract had some effects on mycelium of R. solani; macroscopically the mycelium was shorter, thinner and congregated, whereas microscopically it was smaller, elongated and tended to be colourless compared to control. The treatment of 2% binahong leaf extract on rice seeds decreased the incidence of seedling blight disease with the effectiveness reached 100%. Thus, binahong leaf extract has the potential to suppress sheath blight disease caused by R. solani.

Identification of phenazine-1-carboxylic acid gene (phc CD) from Bacillus pumilus MTCC7615 and its role in antagonism against Rhizoctonia solani.

Bacillus pumilus MTCC7615, a biocontrol agent isolated from rice rhizosphere was characterized to be antagonistic to Rhizoctonia solani, the pathogen causing sheath blight disease of rice. The phenazine-1-carboxylic acid gene (phc CD) of this bacterium was PCR amplified (1400 bp), cloned, and sequenced. The sequence analysis revealed the presence of two ORFs of phc CD gene commonly found in Pseudomonas species. The sequence showed 98% similarity to phc CD gene of the Pseudomonas isolate LBUM223 (DQ788993). The crude antibiotic extract from B. pumilus MTCC7615 was observed to inhibit mycelial growth of R. solani under in vitro conditions. The HPLC analysis of crude antibiotic extract from B. pumilus MTCC7615 confirmed the presence of phenazine. The study has also reported the presence of phc CD gene which is responsible for the synthesis of phenazine-1-carboxylic acid in B. pumilus. The ability of the bacterial isolate to control sheath blight disease in rice seedlings under in vivo conditions was confirmed by the pot culture experiment. The structural and functional genomics of phc C and phc D genes would lead to a better understanding of phenazine biosynthesis in B. pumilus for its efficient utilization in plant protection strategies.

Efektivitas Trichoderma sp. dan Gliocladium sp. sebagai Agen Biokontrol Hayati Penyakit Busuk Pelepah Daun pada Jagung

Sheath blight is an important disease in corn. The disease could cause significant yield loss when infection occurs on susceptible varieties. Disease control using the microorganism antagonist is an alternative for disease management. Research was carried out in a laboratory, greenhouse and field from 2010 to 2012. The research objective was to compare several biological agents for controlling sheath blight disease on corn. In vitro laboratory tests identified that out of sixteen isolates of microorganisms, only 3 isolates which had the potency to suppress the pathogen of sheath blight over 50%, namely TT1; TM; and GM. Conidia development among the three isolates of microorganism the highest was by TT1. In the greenhouse, three isolates of microorganisms showed potential of decreasing sheath blight disease up to 70%. The Gliocladium isolates decreases the disease by 53%. Research results from the field indicated the antagonist had decreased sheath blight disease by 67%. Isolates of Trichoderma and Gliocladium fungus could reduce the yield loss by 23% by suppressing the infection of sheath blight disease.

Potensi Jamur Mikoriza Arbuskular dalam Mengendalikan Penyakit Busuk Pelepah pada Tanaman Jagung

Sheath blight disease is important disease on maize, it caused by Rhizoctonia solani . biological control using arbuscular mycorrhizal is assumed can reduce expansion of the soil borne disease. The experiment was carried out using arranged in completely randomized design of factorial, with different density spore and two isolate of AM fungus ie: Glomus sp and Acaulospora mellea . There were three replicates arbuscular mycorrhizal at 100-300 spore per 10-30 grams propagule was inoculated to each planting hole and inoculated R. solani fungi 30 days after planting. Sheath blight disease observation was taken 10-50 days after inoculation R. solani , while observation their histology stalk and root at 50 days after inoculation of R. solani . The result of the experiment that inoculation of AM fungus with 100-300 spore have poten tial to control sheath blight disease on maize. At the plant infected by AM fungi isolate of Glomus sp its emphasis reach of 21,9%–40,98%, while infected by A. mellea emphasis reach 21,48%–39,93%. The damage of stalk tissue at the plant infected by R. solani was more acute than at the plant infected by both R. solani and mycorrhizal fungus even they had the same symptom, that was an necrosis at their stalk tissue. The plant infected by R. solani and mycorrhizal fungus were not different with the root tissue of healthy plant.

Pengaruh Inokulasi Jamur Mikoriza Arbuskular Terhadap Penyakit Busuk Pelepah Pada Jagung Di Lapangan

Sheath blight caused by Rhizoctonia solani is one of the important diseases in corn. A study on the effect of arbuscular mycorrhizal fungi in controlling sheath blight disease was conducted at pilot project scale in Jambangan Village, Malang District. Three-replicated treatments were arranged in a split-split plot design. The results showed that highest attack intensity occured at treatments without inoculation of arbuscular mycorrhizal fungi. The mean of attack intensity for Wisanggeni variety was 70,05%, while that for GM 30 line was 73,79%. The attack intensity at Wisanggeni variety inoculated with arbuscular mycorrhizal fungi was 45.39% to 49.46%, while that at GM 30 line was 47.52% to 56.12%. The infection of sheath blight disease reduced the production in terms of knob part and seed weight even though the plant was inoculated with arbuscular mycorrhizal fungi of Glomus sp. or Acaulospora mellea . The reduction of knob weight at Wisanggeni variety was 14.2% to 15.0% and that of seed weight was 21.4% to 23,0%. At GM 30 line the reduction of knob part was 12.0% to 17.2%, while that of seed weight was 19.1% to 20.4%.

Detoxification of oxalic acid by Pseudomonas fluorescens strain PfMDU2: Implications for the biological control of rice sheath blight caused by Rhizoctonia solani

Rhizoctonia solani isolates varying in their virulence were tested for their ability to produce oxalic acid (OA) in vitro. The results indicated that the virulent isolates produced more OA than the less virulent isolates. In order to isolate OA-detoxifying strains of Pseudomonas fluorescens, rhizosphere soil of rice was drenched with 100 mM OA and fluorescent pseudomonads were isolated from the OA-amended soil by using King's medium B. These isolates were tested for their antagonistic effect towards growth of R. solani in vitro. Among them P. fluorescens PfMDU2 was the most effective in inhibiting the mycelial growth of R. solani. P. fluorescens PfMDU2 was capable of detoxifying OA and several proteins were detected in the culture filtrate of PfMDU2 when it was grown in medium containing OA. To investigate whether the gene(s) involved in OA-detoxification resides on the plasmids in P. fluorescens PfMDU2, a plasmid-deficient strain of P. fluorescens was generated by plasmid curing. The plasmid-deficient strain (PfMDU2P-) failed to grow in medium containing OA and did not inhibit the growth of R. solani. Both PfMDU2 and PfMDU2P- were tested for their efficacy in controlling sheath blight of rice under greenhouse conditions. Seed treatment followed by soil application of rice with P. fluorescens strain, PfMDU2, reduced the severity of sheath blight by 75% compared with the control, whereas PfMDU2P- failed to control sheath blight disease.

Biological Control of Sheath Blight Disease of Rice by using Antagonistic Bacteria

The study was made to detect and identify antagonistic bacteria to control Rhizoctonia solani, a causal organism of sheath blight (ShB) disease of rice. Isolation of antagonistic bacteria was done from ShB infected rice leaf collected from the districts of Gazipur, Rajshahi, Bogra and Comilla. Fifty isolates of bacteria were isolated. These isolates were tested for antagonism against ShB pathogen of in PDA medium. Among the isolates of antagonistic bacteria (both fluorescent and non fluorescent), eleven produced more than 15 mm inhibition zone, were selected for this study. Remarkable inhibition zone producing ten isolates were selected to observe their antagonistic behaviour by soaking the sclerotia of Rhizoctonia solani and rice seedlings in different hours into bacterial suspension of 3.84 x 107 CFU/ml. Both the in vitro and in vivo rom showed that the sclerotial germination and sheath blight symptom expression were delayed 6-9 days. Soaking of both seedlings and sclerotia with the test bacteria was found most effective to control ShB (38% - 100%) than soaking of seedlings alone with bacterial suspension at different hours. However, BanShbFPS5 (2)B, BanShb738(3), BanShb738(2) and BanShb581(1), the four antagonistic bacterial isolates could be applied as biological agent to control sheath blight disease of rice and they could control sheath blight disease development and could delay the epidemics of the disease. Key words: Biological control; Sheath blight disease; Rhizoctonia solani; Antagonistic bacteria DOI: 10.3329/bjsir.v45i3.6529Bangladesh J. Sci. Ind. Res. 45(3), 225-232, 2010

Optimum period of spraying to control sheath blight disease in early-season rice plant

Optimum period of spraying to control sheath blight disease in early-season rice plant