EVALUATION OF SELECTED VARIETIES OF INDIAN SPINACH (BASELLA ALBA L.) AGAINST CERCOSPORA LEAF SPOT AND ITS MANAGEMENT

A Thesis Submitted to the Faculty of Agriculture Sher-e-Bangla Agricultural University, Dhaka in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE (MS) IN PLANT PATHOLOGY

Consequently, two experiments were conducted in the experimental field of Sher-eBangla Agricultural University, Sher-e-Bangla Nagar, Dhaka to evaluate selected varieties of Indian spinach (Basella Alba L.) against Cercospora leaf spot and to manage the disease using bio-pesticides and selected botanicals in field condition. The 1 st experiment was conducted during the period of April to June, 2018. Three varieties of Indian spinach namely BARI-1, BARI-2 and one local were selected to conduct the experiment and the experiment was designed at Randomized Complete Block Design (RCBD) with twelve replications. During evaluation, at early, mid and late growth stage, the lowest disease incidence (35.25%, 36.92% and 41.95%, respectively) was observed in BARI-2 variety, whereas the highest (59.36%, 64.49% and (71.37%) in local variety of Indian spinach. Similarly, the lowest disease severity (21.60%, 25.85% and 34.85%, respectively) was observed in BARI-2 variety, whereas the highest (45.25%, 52.45% and 62.50%, respectively) in local variety. The highest yield (23.79 t/ha) was recorded in BARI-2 variety, whereas the lowest yield (19.48 t/ha) in local variety. Based on morphological characteristics, the causal organism was identified as Cercospora beticola in CDA media in laboratory. The 2 ii nd experiment was conducted during the period of February to April, 2019 and one local variety was used as planting material. The experiment comprised to manage the Cercospora leaf spot disease using one bio-fungicide and five botanicals. The treatment combinations were- T 0 = Untreated control (without any treatment); T 1 = Seed treated with BAU-biofungicide followed by Allamonda leaf extract and spray at 7 days interval; T 2 = Seed treated with BAUbiofungicide followed by Neem leaf extract and spray at 7 days interval; T 3 = Seed treated with BAU-biofungicide followed by Mustard oil cake and spray at 7 days interval; T 4 = Seed treated with BAU-biofungicide followed by Garlic and spray at 7 days interval; T 5 = Seed treated with BAU biofungicide followed by Biskatali leaf extract and spray at 7 days interval and T 6 = Seed treated with Allamonda leaf extract followed by Neem leaf extract and spray at 7 days interval. The single factor experiment was designed in RCBD with three replications. At early, mid and late growth stage, the lowest disease incidence (3.38%, 4.74% and 5.24%, respectively) was observed in T 2 , while the highest (57.31%, 64.10% and 71.31%, respectively) in T 0 treatment. The lowest disease severity (3.18%, 3.95% and 4.65%, respectively) was observed in T 2 , while the highest (44.86%, 53.11% and 61.56%, respectively) in T 0 treatment at same growth stage. The highest yield (23.09 t/ha) was observed in T 2 and the lowest (19.66 t/ha) in T 0 treatment. Findings of the experiments revealed that BARI 2 showed best performance among all parameters whereas local variety was more susceptible to Cercospora leaf spot diseases and BAU-biofungicide followed by Neem leaf extract and spray at 7 days interval gave better results compare to the other control measures of the study.