http://localhost:8080/xmlui/handle/123456789/30 2026-04-24T15:13:35Z http://localhost:8080/xmlui/handle/123456789/501 ASSESSMENT OF STORAGE FUNGI OF ONION AND ITS EFFECTS ON FIELD CONDITION AHSANUZZAMAN, MD. Two experiments were conducted to assess purple blotch disease in the experimental field (November, 2015 to April 2016) and association of storage fungi with onion bulb in the laboratory (July, 2016 to October, 2016) of the Department of Plant Pathology and Seed Science, SAU, Sylhet. A total of six onion where four Indian viz. Accession 1, Accession 2, Accession 3, Pusa Red and two deshi varieties Faridpuri and Zitka were used in these experiments. The experiments were arranged in Randomized Complete Block Design (RCBD) with three replications. In field experiment, three Indian accessions were sown in two different times as timely sown and late sown. Purple blotch disease was assessed in the field and disease incidence and severity was recorded at four different times (35 DAT, 50 DAT, 65 DAT and 80 DAT) at an interval of 15 days. Accession-1 showed the highest disease incidence 32.4% in timely sown (17 November, 2015) and 38.0% in late sown (21 January, 2015). Highest disease severity was 15.4% in timely sown and 22.27% in late sown among the accessions tested. Disease development was at the highest level in all the accessions at 80 DAT. All accessions showed significant disease development at aged plant and disease development less at timely sown compared to late sown. Disease development of stored onion bulbs was observed at 45 days of storage (DOS) using all six onions in the laboratory. Three important storage fungi namely Aspergillus niger, Penicillium spp. and Fusarium oxysporum were found to be associated with the onion bulbs that caused black mould, blue mould and Fusarium bulb rot disease, respectively. All onions were found to be susceptible to the storage fungi. The lowest (10.34%) disease incidence was found in Zitka variety where the highest (26.6%) was in Pusa Red variety. Black mould disease showed the highest disease incidence among the three diseases. Alternaria porri the causal agent of purple blotch disease was not found in the stored onion bulb. Percent weight loss was measured at three different time (15, 30, 45 DOS) for all the onions at an interval of 15 days. All varieties were significantly different regarding weight loss at 15 days interval in storage condition. Pusa Red variety showed the highest (35.7%) weight loss at 45 days of storage where the lowest (8.7%) was recorded in Zitka. All Indian onions showed higher weight loss compared to deshi onions. 2016-12-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/500 EFFICACY OF BOTANICALS AND CHEMICALS TO CONTROL CERCOSPORA LEAF SPOT DISEASE OF COUNTRY BEAN DEY, SUSMITA The experiment was carried out at the experimental field and laboratory condition of Plant Pathology and Seed Science Department, Sylhet Agricultural University, Sylhet to estimate the prevalence of seed-borne fungal pathogens of country bean and their control measure. In laboratory, different fungal pathogens like Aspergillus niger, Cercospora sesami, Rhizopus stolonifer, Alternaria sp. and Fusarium oxysporum were detected from the collected seed sample by blotter test method. Before sowing, the seeds were treated with six different treatments like as Tı: Autostin 50WP, T2: Aimcozim 50WP, T3: Ata leaf extract (1:2 w/v), T4: Neem leaf extract (1:2 w/v),T5: Biskatali leaf extract (1:2 w/v) and T6: Mahogani leaf extract (1:2 w/v). In field condition, similar four leaf extracts and two chemicals were used as spray solution with 1:4 w/v concentrations. The treatment Tı: Autostin 50WP was found to be most effective in controlling seed borne fungi.The lowest disease incidence (33.3%) and disease severity (21.8%) was found in treatment Tı: Autostin 50WP and gave better response in yield (5.9 t ha-1) compared to other treatments. The results of the present studies suggested that the use of the Autostin 50 WP effectively minimizing Cercospora leaf spot disease severity and increase its yield. 2016-12-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/499 EVALUATION OF DIFFERENT BOTANICALS AND BIOLOGICAL AGENTS TO CONTROL CERCOSPORA LEAF SPOT OF INDIAN SPINACH SARKER, SAMPA The experiments were conducted at the experimental field and laboratory of Plant Pathology and Seed Science Department, Sylhet Agricultural University, Sylhet to explore the prevalence of seed-borne fungal pathogens and their response to botanicals and biological agents. In laboratory experiment, by using Blotter method, the collected seed sample was treated with five different treatments like T2: Custard apple leaf extract (1:2 w/v), T3: Neem leaf extract (1:2 w/v), T4: Biskatali leaf extract (1:2 w/v), T5: Mahagoni leaf extract (1:2 w/v) and T7: control. Different fungal pathogens were detected from the collected seed sample namely Fusarium oxysporum, Alternaria sp., Rhizopus stolonifer, Curvularia sp., and Cercospora sp. The treatment T4 (Biskatali leaf extract) was found to be most effective in controlling seed borne fungi followed by T3 (Neem leaf extract). In case of field experiment, similar five treatments were used as seed treatment along with another two treatments like T1 (Trichocompost) and T6 (Decomposed cowdung) which were used as soil treatment. The four treatments of leaf extracts were also used with concentration 1:4 (w/v) as spray solution in field condition. The lowest disease incidence (28.9%) and disease severity (14.4%) were found in treatments Tı (Trichocompost) and gave best result in term of yield (8.9 t/ha). Treatment T4 (Biskatali leaf extract) and T6 (decomposed cowdung) also gave satisfactory result in yield and found effective to control Cercospora leaf spot of Indian spinach compared to other treatments. The results of the present studies suggested that, use of biological agents (Trichocompost) and botanical treatments especially Biskatali leaf extract has ability to minimize Cercospora leaf spot disease and increase its yield. 2016-12-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/410 STATUS OF RICE FALSE SMUT (Ustilaginoidea virens) DISEASE IN FOUR UNIONS OF NATORE DISTRICT IN BANGLADESH SARKER, MD. MOHAIMAN Rice false smut has become an emerging disease across the world. Its incidence has become serious in Bangladesh during T. Aman season in the last five years. However, the actual level of incidence of the disease in the farmer’s field has not been estimated in this country. This study included a field survey during ripening stage of T. Aman rice in four unions of Natore district in order to estimate the disease incidence, number of smut balls per infected panicle and yield loss, and to ascertain effectiveness of farmer’s fungicide application. The results show that across the four unions, disease incidence, number of smut balls per infected panicle and yield loss were 8.06±2.02%, 2.88±0.17 and 0.72±0.18% (± is 95% confidence interval), respectively. Disease incidence (18.71±5.18%), number of smut balls per infected panicle (3.51±0.39) and yield loss (1.75±0.38%) was the highest in Ramananda Khajura union compared to the other three unions. Among the varieties, BRRI dhan49 incurred the highest disease incidence (18.71±5.18%), number of smut balls per infected panicle (3.51±0.39) and yield loss (1.75±0.38%) than others. The crops which flowered during mid-October to end November showed significantly higher disease incidence than early flowering crops. Fungicide application tended to have reduced the disease, but did not show significant difference with no fungicide application. It is concluded that the strategic management of the disease may be directed specific of the fields where there is a history of the disease through manipulating genotypes and transplanting time. The tactical management of the disease by using fungicides needs to be comprehensively investigated (with respect to products, rate, frequency and timing of application) to ascertain its effectiveness under farmers’ field conditions. 2016-06-01T00:00:00Z