Narrow Brown Leaf Spot Research Articles

Efficacy of Selected Fungicides in Controlling Foliar Diseases of Rice ( Oryza sativa L.)

An experiment was conducted at Sher-e-Bangla Agricultural University, Bangladesh to evaluate the efficacy of different fungicides against major foliar diseases of rice, namely brown spot (Bipolarisoryzae), blast (Pyriculariagrisea), narrow brown leaf spot (Cercosporaoryzae) and sheath rot (Sarocladiumoryzae). Nine fungicides such as Knowin 50 WP 0.2%, Score 250 EC 0.1%, Control 15 EC 0.1%, Proud 25 EC 0.1%, Tilt 250 EC 0.2%, Folicure 250 EW 0.1%, Sunvit 50 WP 0.7%, Cupravit 50 WP 0.7% and Bordeaux Mixture (CuSO4 2.27g: CuO 2.27g: H2O 100ml) were sprayed at maximum tillering stage to control the diseases. All fungicides were effective in reducing the incidence of aforesaid diseases at flowering, milking, dough and maturity stages. The effect of Tilt 250 EC 0.2% (Propiconazole) and Proud 25 EC 0.1% (Propiconazole) were better than the other fungicides in controlling those diseases, resulted higher yield. In maturity stage, the highest disease severity of brown spot and sheath rot were found in the control (untreated) while the lowest severity was observed in Tilt 250 EC 0.2%. Proud 25 EC 0.1% also showed the lowest severity of blast and narrow brown spot at maturity stage. The highest grain yield (4.75t ha-1) was recorded at treatment, Tilt 250 EC 0.2%. Therefore, Tilt 250 EC 0.2% and Proud 25 EC 0.1% can be recommended to control the foliar diseases of rice which help to increase the grain yield of that crop.

Field efficacy of fungicides for management of sheath blight and narrow brown leaf spot of rice

Sheath blight (caused by Rhizoctonia solani AG1-IA) and narrow brown leaf spot (NBLS, caused by Cercospora janseana) are among the most important diseases affecting rice production in Texas and in other regions in the southern United States. Strobilurin fungicides have been used extensively to manage these two diseases, especially sheath blight. Unfortunately, heavy reliance on use of fungicides with a single mode of action has induced the development of the strobilurin-resistant isolates of R. solani AG-1 IA in the U.S. NBLS, once considered a minor disease in the U.S, is growing in its occurrence and severity, while little scientific information is available on NBLS management. This created an urgent need for identifying other effective fungicides with different modes of action. A 6-year field study was conducted on rice to evaluate the efficacy of newly registered and unregistered fungicides in comparison to common fungicides for management of sheath blight and NBLS diseases. Single applications of the fungicides containing azoxystrobin, propiconazole, azoxystrobin plus propiconazole, trifloxystrobin plus propiconazole, fluxapyroxad, pyraclostrobin, flutolanil and antibiotics (validamycin and kasugamcyin) were made at the late booting stage. Sheath blight and NBLS severities were rated prior to harvest. All the fungicide treatments were effective in reducing sheath blight severity compared to the untreated control in each year. Propiconazole and fluxapyroxad were more effective in reducing NBLS than other fungicides. Along with reduced sheath blight and NBLS severities, fungicide-treated plots had higher yields than untreated plots.

Effect of cultivar susceptibility and planting date on narrow brown leaf spot progression in rice

Narrow brown leaf spot (NBLS) of rice (Oryza sativa L.) is caused by Cercospora janseana (Racib). O. Const. (Synonyms: Cercospora oryzae Miyake, Passalora janseana Racib. U.). Experimental studies were conducted in Louisiana to study NBLS progression in resistant to very susceptible cultivars at different planting dates. The very susceptible cultivars CL131 and Cheniere, susceptible CL111, moderately susceptible CL151, and resistant cultivars, Della and Presidio were planted in mid-April and mid-May plantings. Weekly disease assessments began at 45 days after sowing (DAS) and the final disease assessments were done at 109 DAS. Results revealed that AUDPC and final NBLS severity were greater in very susceptible and susceptible cultivars as compared to resistant cultivars. The AUDPC for mid-May plantings were greater for all cultivars. AUDPC increased with increasing susceptibility rating in the mid-April planting. Early onset of NBLS was observed in very susceptible and susceptible cultivars regardless of planting date. Significant interactions were detected between cultivar and planting date for AUDPC and final disease but were non-significant for apparent infection rate. Apparent NBLS infection rate was greatest in the highly susceptible Cheniere and CL131 in the mid-May planting. Apparent infection rates were less in the susceptible and moderately susceptible cultivars and least for the resistant cultivars in both plantings.

Comparative efficacy of BAU-Biofungicide and synthetic fungicides in management of diseases of rice (Oryza sativa L.) for quality seed production

Extracts of garlic (Allium sativum L.) and neem (Azadirachta indica A. Juss.), BAU-Biofungicide (Trichoderma based preparation), Potent 250 EC (Propiconazole) and Bavistin DF (Carbendazim) were evaluated under laboratory and field conditions in controlling diseases of rice cv BR11 for quality seed production. BAU-Biofungicide (2%) showed significant effect in controlling mycelial growth of (Bipolaris oryzae (Breda de Haan) Shoem.), Cercospora oryzae I. Miyake, Rhizoctonia solani Kuhn. and Ustilaginoidea virens (Cke.) Tak. in-vitro test and also reduced disease severity of brown spot, narrow brown leaf spot, sheath blight and false smut as of Propiconazole (0.1%). Carbendazim (0.1%) showed better result in inhibiting the disease severity of narrow brown leaf spot and sheath blight. Propiconazole (0.1%) increased highest 26.40% grain yield, while BAU-Biofungicide (3%) increased 20.42% grain yield over untreated control in the field. Formation of maximum (74.33%) apparently healthy seed, highest germination (98.00%) increased 36.49% of vigor index by BAU-Biofungicide (2%) over control. Major seed borne fungi of harvested seeds were controlled by foliar application of BAU-Biofungicide.

Effect of planting date, fungicide timing and cultivar susceptibility on severity of narrow brown leaf spot and yield of rice

Narrow brown leaf spot (NBLS) of rice (Oryza sativa L.) is caused by Cercospora janseana (Racib). O. Const. (Synonyms: Cercospora oryzae Miyake, Passalora janseana Racib. U.). Experimental studies were conducted at Rice Research Station, Louisiana State University, and Agricultural Center, Crowley, to manage NBLS by fungicide application of propiconazole at different growth stages of rice cultivars having different susceptibility levels to NBLS in different planting dates. Results of these studies revealed that April (early) had less NBLS severity as compared to May (late) planting. Very susceptible cultivars, CL131 and Cheniere, had the highest and resistant cultivars, Della and Presidio, had the lowest NBLS severity at both the planting dates. Propiconazole application significantly reduced the NBLS severity in comparison to untreated. Fungicide application at panicle initiation was the most effective time to manage NBLS on the very susceptible and susceptible cultivars at both planting dates. NBLS on moderately susceptible cultivars was best managed by applying fungicide either at panicle initiation or early boot stage in early planting but panicle initiation was the best time to apply fungicide in late planting. Resistant cultivars did not need fungicide in April planting but did need in May planting. Rice yield was determined to be higher in April than May planting. Fungicide application at early boot stage protected the yield by 9.4% in April planting and 34.2% when applied at panicle initiation in May. Susceptible cultivar, Cheniere, exhibited the greatest yield and resistant cultivars had lowest yield in both the planting dates regardless of its susceptibility level to NBLS. Yield of very susceptible to susceptible cultivars was reduced in late planting but no effect was observed on yield of moderately susceptible and resistant cultivars.

Eco-Friendly Management of Rice Diseases

Comparative efficacy of BAU-Biofungicide (2%), a product of Trichoderma harzianum, Garlic (Allium sativum) clove extract (5%), Allamanda(Allamanda cathartica) leaf extract (5%), Bion (25ppm), Amistar (0.1%) and Tilt 250EC (0.1%) were evaluated for eco-friendly managementof diseases of rice cv. BRRI Dhan-49 under field and laboratory conditions from July,2013 to March,2014. The field experiment was carriedout following Randomised Complete Block Design and the laboratory experiments were done following Completely Randomized Design.Brown spot, Narrow brown leaf spot, Bacterial leaf blight and Sheath blight were recorded in the field. The lowest incidence of brown spotand narrow brown leaf spot was observed in plots treated with BAU-Biofungicide and that of bacterial leaf blight was observed in plots sprayedwith Allamanda leaf extract. In case of sheath blight, the lowest incidence was observed in BAU-Biofungicide sprayed plots. The highest grainyield (3680.34kg/ha) was recorded in plots sprayed with BAU-Biofungicide which is 40.56% higher over control. The highest seed germination(%) was recorded when seeds were treated with Garlic clove extract (89.29%) followed by BAU-Biofungicide (87.30%). The prevalence ofseed-borne fungi was investigated by blotter method. The identified seed-borne fungal species were Bipolaris oryzae, Fusarium oxysporum,Fusarium moniliforme, Curvularia lunata, Aspergillus niger and Aspergillus flavus. Maximum reduction of seed-borne infection of pathogenswas obtained by treating seeds with BAU-Biofungicide (2% of seed weight).DOI: http://dx.doi.org/10.3126/ijasbt.v3i1.11977 Int J Appl Sci Biotechnol, Vol. 3(1): 80-88

Evaluation of some selected seed treatments against leaf blast, brown spot and narrow brown leaf spot diseases of hybrid rice

Evaluation of some selected seed treatments against leaf blast, brown spot and narrow brown leaf spot diseases of hybrid rice

First report of narrow brown leaf spot disease of rice in West Bengal, India

During the 2001 wet season (Jun - Nov), the popular, high-yielding, and widely adapted cultivar Swarna was observed to have many linear red-brown spots. These had light-colored margins and light brown to gray centers. Observed on leaves during the later (dough and mature grain) growth stages, the spots were restricted between the veins. The experimental plots of the ricewheat system of the Rice Research Station, Chinsurah, were exposed to these weather conditions: mean maximum temperature, 32°C; mean minimum temperature, 25°C; relative humidity, 98%; and rainfall, 942 mm. A similar type of lesions was also found on the leaf sheaths, pedicels, and glumes. The lesions were 2–10 x 0.5–1 mm and they coalesced to form long, threadlike brown lesions parallel to the veins on the entire leaves.

First Report of the Occurrence of White Leaf Streak in Louisiana Rice.

White leaf streak, caused by Mycovellosiella oryzae (Deighton and Shaw) Deighton (syn. Ramularia oryzae), was found in Louisiana rice. The symptoms closely resemble those of narrow brown leaf spot caused by Cercospora janseana (Racib.) O. Const. (syn. C. oryzae (Miyake)), and it is difficult to distinguish between these two diseases. Initially both produce similar elongated light brown lesions, but later the lesions of white leaf streak become wider with a whitish center and are surrounded by a narrow light brown margin (2,3). The disease was first observed at the Rice Research Station, Crowley, LA, in 1996 on older leaves of the cultivar Lemont at maturity. Leaves containing the unusual lesion types were placed in a moist chamber and incubated at 28°C for 5 days. Abundant conidia were produced and the fungus was isolated on acidified potato dextrose agar (APDA) by single spore isolation and by plating infected tissues after surface sterilization in 40% Clorox for 10 to 15 min. The colonies grew slowly on APDA and were dark gray in color. The conidia formed in branched chains or singly. They were hyaline, cylindrical with tapering ends and a thick hilum; 0 to 3 septate, and 15 to 35 m long (1,3). Pathogenicity tests were conducted in the greenhouse on the Lemont and Cypress rice cultivars by spraying a conidial suspension (103-4 conidia per ml) onto leaf blades at boot stage. Conidia were produced by growing the fungus on PDA for 10 to 14 days. Inoculated plants were placed inside a humid chamber in a greenhouse and maintained for 4 to 5 weeks. Many elongated lesions similar to those observed in the field were produced 3 to 4 weeks after inoculation. Reisolation from these lesions yielded M. oryzae. With the same methods, 45 cultivars and lines were inoculated to determine their reactions to this disease. Most of the cultivars grown in the southern United States were moderately susceptible or susceptible to white leaf streak. Foreign cultivars tested, including BR-7, BR-11, Cica-4, Cica-6, Cica-7. Cica-8, Cica-9, Oryzica llanos, Rax clear, Teqing, and Tetep, were resistant. In 1997, the disease was found prevalent on many cultivars grown at the Rice Research Station, Crowley, LA. As symptoms of both white leaf streak and narrow brown leaf spot were sometimes observed on the same leaf; it is possible that the disease has been present, but not identified as a separate disease because of the similarity of the symptoms of the two diseases. A thorough survey is necessary to determine the extent of its occurrence and further studies are necessary to determine its yield loss potential. At present it appears to be a minor problem for Louisiana rice. White leaf streak has previously been recorded from Papua New Guinea on cultivated Oryza sativa, and from the Solomon Islands, Sabah, Nizeria, and Sierra Leone on cultivated O. glabberima Steudel and on wild perennial rice O. berthii A. Chev. (2). This is the first report of white leaf streak on cultivated rice in the United States.

Field Resistance to False Smut (FS) and Narrow Brown Leaf Spot (NBLS) in Eastern Uttar Pradesh

Field Resistance to False Smut (FS) and Narrow Brown Leaf Spot (NBLS) in Eastern Uttar Pradesh

Status of Brown Spot (BS) and Narrow Brown Leaf Spot (NBLS) in Eastern Uttar Pradesh (UP), India

Status of Brown Spot (BS) and Narrow Brown Leaf Spot (NBLS) in Eastern Uttar Pradesh (UP), India

Seasonal Incidence of Brown Spot and Narrow Brown Leaf Spot in the Thanjavur Delta, India

Seasonal Incidence of Brown Spot and Narrow Brown Leaf Spot in the Thanjavur Delta, India

Rice Diseases in Nigeria

Abstract The two major fungal diseases of rice in Nigeria are rice blast (Pyricularia oryzae Cav.) and brown spot (Cochliobolus miyabeanus (Ito and Kuribayashi) Dreschler ex Dastur). The loss in grain yield attributable to these diseases ranges from 11.5–39.6% and 12–43% respectively, Mancozeb, blasticidin-S, fentin hydroxide, benomyl and edifenphos as foliar sprays effectively control rice blast in the laboratory and field. Brown spot is controlled by spraying with thiram, mancozeb or blasticidin-S. A more useful approach to the control of these diseases being adopted in Nigeria is the search for horizontally resistant varieties. Other fungal diseases of rice in Nigeria are the green smut (Ustilaginoidea virens (Cooke) Tak.), basal sheath rot (Rhizoctonia solani Kuhn), sheath blight (Corticium sasakii (Shirai), Matsumoto.), leaf scald (Rhynchosporium oryzae Hashioka and Yokogi), narrow brown leaf spot (Cercospora oryzae Miyake) and bakanae disease, a foot rot caused by Fusarium moniliforme Sheldon. Two s...

Cercospora oryzae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Cercospora oryzae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Oryza saliva . DISEASE: Narrow brown leaf spot of rice. The fungus has been reported on Panicum repens ( Plant Disease Reporter 54: 272, 1970). The linear leaf lesions are 2-10 mm long, usually up to 1-1.5 mm wide, the long axis parallel to that of the leaf; centre dark brown with the border fading as the outer margin is reached. Lesions on the sheath are similar to those on the leaf, whilst those on the glumes are shorter and tend to lateral spread. On susceptible cvs. the leaf lesions are wider and lighter brown whereas on resistant ones they are narrow and a more uniform dark brown. Symptoms are usually extensive during the later stages of growth and should not be confused with those caused by Ramularia oryzae Deighton & Shaw (white leaf streak; 40, 104). GEOGRAPHICAL DISTRIBUTION: Widespread in the tropics and S. and S.E. USA (CMI Map 71, ed. 3, 1967). TRANSMISSION: No studies reported.