scholarly journals Survey and Identification of Rice Diseases in South Gondar Zone, Amhara Region, Ethiopia

2019 ◽  
pp. 123-131
Author(s):  
Tekalign Zeleke ◽  
Muluadam Birhan ◽  
Wubneh Ambachew
Keyword(s):  
Brown Rot ◽  
Brown Spot ◽  
Loss Assessment ◽  
Leaf Blast ◽  
Panicle Blast ◽  
Disease Surveys ◽  
Rice Disease ◽  
Cropping Seasons ◽  
South Gondar ◽  
Sheath Rot

Disease surveys were conducted in rice grown districts of Libokemkem, Dera and Fogera in south Gondar zone in 2016 and 2017 cropping seasons. The study was designed to identify and record rice disease flora, their distribution in the districts, prioritize according to the importance and document for future use. Forty-six and 48 rice fields were assessed from nine Peasant Association (PA) in 2016 and 2017 cropping seasons, respectively. Rice diseases; Leaf blast, Panicle Blast, Brown spot, Sheath rot, Sheath brown rot, Sheath Blight, Bacterial blight, Rice Yellow Motile Virus, Kernel smut, Downy mildew were identified in 2016 cropping season and nine rice diseases: Leaf blast, Panicle Blast, Neck Blast, Node blast, Brown spot, Sheath rot, Sheath brown rot, Rice Yellow Motile Virus, Kernel smut were identified in 2017. The overall mean prevalence of sheath rot and sheath brown rot diseases were above 60%, while the others had prevalence below 21%. The incidences and severities of these two diseases were higher than the other diseases implying that both diseases were important. In the present studies many rice diseases were recorded in lowland ecosystem as compared to upland ecosystem. From the assessment X-jigna cultivar was more susceptible to rice disease and followed by Gumera. The results indicate that a sheath rot, and sheath brown rot, were important across the districts and years. Loss assessment studies should be initiated in order to know the yield damage caused by the diseases.

scholarly journals BNKR-1 (Dhiren) – A newly released late duration high-yielding rice variety an alternative to Swarna (MTU 7029) for West Bengal, India

2014 ◽  
Vol 6 (2) ◽  
pp. 869-871
Author(s):  
G. K. Mallick ◽  
I. Dana ◽  
K. Jana ◽  
A. Ghosh ◽  
A. Biswas
Keyword(s):  
West Bengal ◽  
Rice Variety ◽  
National Level ◽  
Brown Spot ◽  
Research Station ◽  
Average Yield ◽  
Leaf Blast ◽  
Yield Trial ◽  
Moderately Resistant ◽  
Sheath Rot

BNKR – I (Dhiren), a new late duration high yielding rice variety developed at Rice Research Station, Bankura, West Bengal, India was released by “State Variety Release Committee” (SVRC), West Bengal in 2011 for cultivation in irrigated late areas of West Bengal, India. Before release as BNKR – I (Dhiren), this rice culture completed three years of national testing (2008-2010) in the designation of CN 1340-76-1-BNKR 23-7-1 (IET 20760) and had been recommended for release in irrigated areas of Bihar and West Bengal under transplanted condition in 46th National Group Meeting on Rice organized by Directorate of Rice Research (ICAR), Hyderabad, India during April 2011. It gave 7.65 to 12.12% yield advantage over national check in national level. Not only that this culture of rice tested extensively in the farm of Rice research Station, Bankura, West Bengal and farmer’s field. It showed 11.64% and 19.30% yield advantage during 2006 and 2007 in observational trial, 10.44 to 14.38% yield advantage in on station yield trial during 2008-2010 and 12.51 to 17.93% yield advantage in farmer’s field during 2009 and 2010 over Swarna (MTU 7029), which is the most popular rice variety of West Bengal. BNKR – I (Dhiren) is non-lodging, non-shattering and late maturing variety (seed to seed : 142 days). It is moderately resistant to leaf blast, neck blast, brown spot, sheath rot and leaf folder. It’s average yield is 5000 – 5500 kg ha-1 . Grain type is short bold. It is expected that BNKR – I (Dhiren) can be able to replace Swarna (MTU 7029), the most popular rice variety of West Bengal, India.

scholarly journals Automatic Diagnosis of Rice Diseases Using Deep Learning

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruoling Deng ◽  
Ming Tao ◽  
Hang Xing ◽  
Xiuli Yang ◽  
Chuang Liu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Sheath Blight ◽  
Brown Spot ◽  
Smartphone App ◽  
Ensemble Model ◽  
Leaf Blast ◽  
Automatic Diagnosis ◽  
Neck Blast ◽  
Rice Disease ◽  
False Smut

Rice disease has serious negative effects on crop yield, and the correct diagnosis of rice diseases is the key to avoid these effects. However, the existing disease diagnosis methods for rice are neither accurate nor efficient, and special equipment is often required. In this study, an automatic diagnosis method was developed and implemented in a smartphone app. The method was developed using deep learning based on a large dataset that contained 33,026 images of six types of rice diseases: leaf blast, false smut, neck blast, sheath blight, bacterial stripe disease, and brown spot. The core of the method was the Ensemble Model in which submodels were integrated. Finally, the Ensemble Model was validated using a separate set of images. Results showed that the three best submodels were DenseNet-121, SE-ResNet-50, and ResNeSt-50, in terms of several attributes, such as, learning rate, precision, recall, and disease recognition accuracy. Therefore, these three submodels were selected and integrated in the Ensemble Model. The Ensemble Model minimized confusion among the different types of disease, reducing misdiagnosis of the disease. Using the Ensemble Model to diagnose six types of rice diseases, an overall accuracy of 91% was achieved, which is considered to be reasonably good, considering the appearance similarities in some types of rice disease. The smartphone app allowed the client to use the Ensemble Model on the web server through a network, which was convenient and efficient for the field diagnosis of rice leaf blast, false smut, neck blast, sheath blight, bacterial stripe disease, and brown spot.

scholarly journals The OsOXO2, OsOXO3 and OsOXO4 Positively Regulate Panicle Blast Resistance in Rice

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jingfang Dong ◽  
Lian Zhou ◽  
Aiqing Feng ◽  
Shaohong Zhang ◽  
Hua Fu ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Blast Resistance ◽  
Aba Signaling ◽  
Leaf Blast ◽  
Expression Levels ◽  
Panicle Blast ◽  
Localization Analysis ◽  
Sa Signaling

Abstract Background Although panicle blast is more destructive to yield loss than leaf blast in rice, the cloned genes that function in panicle blast resistance are still very limited and the molecular mechanisms underlying panicle blast resistance remain largely unknown. Results In the present study, we have confirmed that the three Oxalate oxidase (OXO) genes, OsOXO2, OsOXO3 and OsOXO4 from a blast-resistant cultivar BC10 function in panicle blast resistance in rice. The expression of OsOXO2, OsOXO3 and OsOXO4 were induced by panicle blast inoculation. Subcellular localization analysis revealed that the three OXO proteins are all localized in the nucleus and cytoplasm. Simultaneous silencing of OsOXO2, OsOXO3 and OsOXO4 decreased rice resistance to panicle blast, whereas the OsOXO2, OsOXO3 and OsOXO4 overexpression rice plants individually showed enhanced panicle blast resistance. More H2O2 and higher expression levels of PR genes were observed in the overexpressing plants than in the control plants, while the silencing plants exhibited less H2O2 and lower expression levels of PR genes compared to the control plants. Moreover, phytohormone treatment and the phytohormone signaling related gene expression analysis showed that panicle blast resistance mediated by the three OXO genes was associated with the activation of JA and ABA signaling pathways but suppression of SA signaling pathway. Conclusion OsOXO2, OsOXO3 and OsOXO4 positively regulate panicle blast resistance in rice. The OXO genes could modulate the accumulation of H2O2 and expression levels of PR gene in plants. Moreover, the OXO genes mediated panicle blast resistance could be regulated by ABA, SA and JA, and may be associated with the activation of JA and ABA signaling pathways but suppression of the SA signaling pathway.

Sarocladium oryzae. [Descriptions of Fungi and Bacteria].

1980 ◽  
Author(s):  
B. L. K. Brady
Keyword(s):  
Oryza Sativa ◽  
Geographical Distribution ◽  
Leaf Sheath ◽  
Fungal Attack ◽  
Rice Disease ◽  
Sheath Rot

Abstract A description is provided for Sarocladium oryzae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Oryza sativa (rice). DISEASE: Sheath rot. This occurs in the upper leaf sheath enclosing young panicles and starts as oblong or irregular lesions with brownish margins and greyish centres, 0.5-1.5 cm long, which later enlarge and coalesce. Whitish mycelium may be seen in the centre of the lesions and occasionally inside the rotted sheaths. Severely affected panicles do not emerge, the effect being known as choking. The symptoms are evidently indistinguishable from those associated with S. attenuatum. GEOGRAPHICAL DISTRIBUTION: India, Bangladesh, Brunei, Kenya, Nigeria. Although it is not always possible when 'Acrocydndrium oryzae' is reported in the earlier literature to know whether S. oryzae or S. attenuatum is intended, the distribution of the former extends into S.E. Asia and the latter into N. America. TRANSMISSION: By conidial dispersal. Fungal attack is often associated with damage by pests - the boring beetle, Corticarina gibbosa (Amin et al.) or the mite Steneotarsonemus madecassus (Hsieh et al., 1977 with 'Acrocylindrium oryzae') and S. spinki (Chien & Huang, 1979).

Studies on the behaviour of some fungal diseases of rice in the mangrove swamp ecology at Warri, south eastern Nigeria

2003 ◽  
Vol 51 (4) ◽  
pp. 429-436
Author(s):  
E. A. Maji ◽  
E. D: Imolehin
Keyword(s):  
Disease Incidence ◽  
Block Design ◽  
Rice Variety ◽  
N Fertilization ◽  
Brown Spot ◽  
Bipolaris Oryzae ◽  
Southeastern Nigeria ◽  
Mangrove Swamp ◽  
Main Plot ◽  
Cropping Seasons

Studies on the ecological behaviour of Cochliobolus miyabeanus (Ito et Kurib.) Drechsl. ex Dast., syn. Bipolaris oryzae (Breda de Haan Shoem.), the causal agent of brown spot in rice (Oryza sativa L.), were carried out in the tidal mangrove swamp at Warri Experimental Farm, Southeastern Nigeria. A split randomised complete block design with four replications was used. Monthly transplantings from July to September formed the main plot, which was subdivided into control and N-treated subplots. Disease incidence increased when transplanting was delayed. This was probably due to the fact that flowering coincided with environmental conditions favourable for disease development from November to February. Nitrogen fertilization at 40 kg N/ha significantly (P=0.05) reduced C. miyabeanus incidence in 1997/1998, but not in the 1998/1999 and 1999/2000 cropping seasons at the same site. The grain yields of ROK 5, a medium-duration improved rice variety (approx. 150 days), were significantly (P=0.05) reduced in late-transplanted crops (September to November) in spite of adequate N fertilization. Mangrove mud was not an important source of C. miyabeanus propagules. The incidence of leaf scald caused by Monographella albescens (Thum) Parkinson, Sivanesan and Booth syn. Microdochium oryzae (Hashioka and Yokogi) Samuels and Hallet, and of leaf smut caused by Etyloma oryzae Miyake was generally stimulated by N application.

scholarly journals Research Priorities for Rice Pest Management in Tropical Asia: A Simulation Analysis of Yield Losses and Management Efficiencies

2004 ◽  
Vol 94 (7) ◽  
pp. 672-682 ◽  
Author(s):  
Laetitia Willocquet ◽  
Francisco A. Elazegui ◽  
Nancy Castilla ◽  
Luzviminda Fernandez ◽  
Kenneth S. Fischer ◽  
...  
Keyword(s):  
Pest Management ◽  
Management Strategies ◽  
Research Priorities ◽  
Sheath Blight ◽  
Brown Spot ◽  
Yield Losses ◽  
Leaf Blast ◽  
Tropical Asia ◽  
Neck Blast ◽  
Rice Pest

A simulation study was conducted to assess the current and prospective efficiency of rice pest management and develop research priorities for lowland production situations in tropical Asia. Simulation modeling with the RICEPEST model provided the flexibility required to address varying production situations and diverse pest profiles (bacterial leaf blight, sheath blight, brown spot, leaf blast, neck blast, sheath rot, white heads, dead hearts, brown plant-hoppers, insect defoliators, and weeds). Operational definitions for management efficacy (injury reduction) and management efficiency (yield gain) were developed. This approach enabled the modeling of scenarios pertaining to different pest management strategies within the agroecological contexts of rice production and their associated pest injuries. Rice pests could be classified into two broad research priority-setting categories with respect to simulated yield losses and management efficiencies. One group, including weeds, sheath blight, and brown spot, consists of pests for which effective pest management tools need to be developed. The second group consists of leaf blast, neck blast, bacterial leaf blight, and brown plant-hoppers, for which the efficiency of current management methods is to be maintained. Simulated yield losses in future production situations indicated that a new type of rice plant with high-harvest index and high-biomass production (“New Plant Type”) was more vulnerable to pests than hybrid rice. Simulations also indicated that the impact of deployment of host resistance (e.g., through genetic engineering) was much larger when targeted against sheath blight than when targeted against stem borers. Simulated yield losses for combinations of production situations and injury profiles that dominate current lowland rice production in tropical Asia ranged from 140 to 230 g m-2. For these combinations, the simulated efficiency of current pest management methods, expressed in terms of relative yield gains, ranged from 0.38 to 0.74. Overall, the analyses indicated that 120 to 200 × 106 tons of grain yield are lost yearly to pests over the 87 × 106 ha of lowland rice in tropical Asia. This also amounts to the potential gain that future pest management strategies could achieve, if deployed.

scholarly journals Spatiotemporal Survey of Multiple Rice Diseases in Irrigated Areas Compared to Rainfed Lowlands in the Western Burkina Faso

Plant Disease ◽  
2021 ◽  
Author(s):  
Mariam Barro ◽  
Abalo Itolou Kassankogno ◽  
Issa Wonni ◽  
Drissa SEREME ◽  
Irénée SOMDA ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Fungal Pathogens ◽  
Management Practices ◽  
Brown Spot ◽  
Leaf Blast ◽  
Rice Leaf ◽  
Yellow Mottle ◽  
Rice Leaf Blast ◽  
Study Sites ◽  
Western Burkina Faso

Multiple constraints affect rice yields and global production in West Africa. Among these constraints are viral, bacterial and fungal pathogens. We aimed to describe the spatiotemporal patterns of occurrence and incidence of multiple rice diseases in farmers’ fields in contrasting rice growing systems in western Burkina Faso. For this purpose, we selected a set of three pairs of sites, each comprising an irrigated area and a neighboring rainfed lowland, and studied them over four consecutive years. We first performed interviews with the rice farmers to better characterize the management practices at the different sites. This study revealed that the transplanting of rice and the possibility of growing rice twice a year are restricted to irrigated areas, while other practices, such as the use of registered rice cultivars, fertilization and pesticides, are not specific but differ between the two rice growing systems. Then, we performed symptom observations at these study sites to monitor the following four diseases: yellow mottle disease, Bacterial Leaf Streak (BLS), rice leaf blast and brown spot. The infection rates were found to be higher in irrigated areas than in rainfed lowlands, both when analyzing all observed symptoms together (any of the four diseases) and when specifically considering each of the two diseases: BLS and rice leaf blast. Brown spot was particularly prevalent in all six study sites, while yellow mottle disease was particularly structured geographically. Various diseases were frequently found together in the same field (co-occurrence) or even on the same plant (coinfection), especially in irrigated areas.

scholarly journals CITPATH: Diagnostic and Hypertext Software for Fungal Diseases of Citrus Foliage and Fruit

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 899A-899
Author(s):  
James J. Ferguson ◽  
Fedro S. Zazueta ◽  
Juan I. Valiente
Keyword(s):  
Management Strategies ◽  
Brown Rot ◽  
Fungal Diseases ◽  
Brown Spot ◽  
Cd Rom ◽  
Fruit Drop ◽  
Yield And Quality ◽  
Diagnostic Key ◽  
Florida Citrus ◽  
Development And Management

Fungal diseases have their greatest impact on citrus in Florida by reducing tree vigor, fruit yield, and quality. Given the complex etiology of these diseases, this software was developed to facilitate diagnosis of symptoms and to explain the dynamics of Alternaria brown spot of mandarins, greasy spot, melanose, Phytophthora brown rot, post-bloom fruit drop, and sour orange scab. CITPATH includes a diagnostic key to identify symptoms of the major fungal diseases of citrus foliage and fruit in Florida and a hypertext program containing a description and graphic display of symptoms, maps of geographic occurrence, diagrams of disease development, and management strategies. Users can also consult a list of citrus cultivars susceptible to specific diseases and a reciprocal list of diseases affecting specific cultivars. Chemical control methods are discussed briefly with reference to the current Florida Citrus Spray Guide, a hardcopy of which is included with the software purchase. Developed for commercial growers, county extension programs, citrus horticulture classes, and master gardeners, this software is available on CD-ROM disks containing other citrus databases and as a separate disk for MS-DOS-based computers.

scholarly journals Auxin, abscisic acid and jasmonate are the central players in rice sheath rot caused by Sarocladium oryzae and Pseudomonas fuscovaginae

2020 ◽  
Author(s):  
Kaat Peeters ◽  
Maarten Ameye ◽  
Kristof Demeestere ◽  
Kris Audenaert ◽  
Monica Hofte
Keyword(s):  
Abscisic Acid ◽  
Host Response ◽  
Wild Type ◽  
Yield Parameters ◽  
Mutant Strains ◽  
Rice Disease ◽  
Membrane Bound ◽  
Helvolic Acid ◽  
Sheath Rot

Abstract Sheath rot is an emerging rice disease that causes severe yield losses worldwide. The main causal agents are the toxin producers Sarocladium oryzae and Pseudomonas fuscovaginae. The fungus S. oryzae produces helvolic acid and cerulenin and the bacterium P. fuscovaginae produces cyclic lipopeptides. Helvolic acid and the lipopeptide, fuscopeptin, inhibit membrane-bound H+-ATPase pumps in the rice plant. To manage rice sheath rot, a better understanding of the host response and virulence strategies of the pathogens is required. This study investigated the interaction of the sheath rot pathogens with their host and the role of their toxins herein. Japonica rice was inoculated with high- and low-helvolic acid-producing S. oryzae isolates or with P. fuscovaginae wild type and fuscopeptin mutant strains. During infection, cerulenin, helvolic acid and the phytohormones abscisic acid, jasmonate, auxin and salicylic acid were quantified in the sheath. In addition, disease severity and grain yield parameters were assessed. Rice plants responded to high-toxin-producing S. oryzae and P. fuscovaginae strains with an increase in abscisic acid, jasmonate and auxin levels. We conclude that, for both pathogens, toxins play a core role during sheath rot infection. S. oryzae and P. fuscovaginae interact with their host in a similar way. This may explain why both sheath rot pathogens cause very similar symptoms despite their different nature.

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