Rice is the most staple cereal crop of Bangladesh and rice blast caused by Magnaporthe oryzae oryzae (MoO) has become a major factor limiting rice yield in Bangladesh and throughout the world. Eight botanicals extracted both in water and ethanol namely Kalijira (Nigella sativa), Turmeric (Curcuma longa), Ginger (Zingiber officinalis), Garlic (Allium sativum), Onion (Allium cepa), Neem (Azadirachta indica), Allamanda (Allamanda cathartica) and Aloevera (Aloe vera) were tested against MoO in vitro in the Mycology Laborato-

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The present research work was conducted to evaluate the efficacy of eight fresh botanicals namely Azadirachta indica (Neem leaf), Allium cepa (Onion bulb), Allium sativum (Garlic), Curcuma longa (Turmeric), Zingiber officinale (Ginger), Allamanda cathartica (Allamanda leaf), Nigella sativa (Black cumin) and Aloe vera (Aloe vera) against Magnaporthe oryzae triticum (MoT) and solvent, ethanol (95%) was used for the phytochemical extraction of various plant parts. Three concentrations namely 1:1 (w/v), 1:0.50 (w/v) and 1:0.25 (w/v) of plant parts and ethanol were used for botanical extraction. The antifungal activity of botanicals against a virulent MoT isolate CHMoT07 was evaluated in-vitro using poison food technique. The lowest mycelia growth was recorded with Aloe vera (Aloe vera leaf) extracts and Nigella sativa (Black cumin seeds) extracts @ 1:1 w/v and @ 1:0.25 w/v with growth rate of 3.00 mm and 3.33 mm respectively at 7 days after inoculation, whereas the highest mycelia growth rate of MoT isolates was recorded in control plates both at 7 DAI and 14 DAI under in-vitro condition.

Aims: To survey and study morphological characterization of rice blast caused by Magnaporthe oryzae oryzae (MoO) that has become a major factor limiting rice yield throughout the world. Study Design: Complete Randomized Design (CRD). Place and Duration of Study: Mycology Laboratory, Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka from June 2018 to December 2019. Methodology: A survey was done in three northern districts of Bangladesh namely Gaibandha (Gobindogonj and Mohimagonj), Dinajpur (Birampur) and Bogura (Dupchanchia), disease incidence and severity was recorded and samples were collected. Five different media including Water Agar (WA), Potato Dextrose Agar (PDA), Potato Sucrose Agar (PSA), Rice flour Yeast Agar (RfYA) and Oat Meal Agar (OMA) were used to culture MoO. Colony characters like growth character, color, surface structure and shape of 28 MoO isolates were recorded in PDA. Results: Among the three surveyed districts, the highest incidence (84.26%) of blast was recorded from Gobindogonj with a severity score of 7. The highest severity score 9.00 (65%) of blast was recorded in Mohimagonj where blast incidence was only 29.12%. Among the five different growth media highest mycelia growth was observed in Oat Meal Agar (20 mm) and lowest in Water Agar (10mm) at 7 DAI. Colony color of all the isolates was whitish grey to blackish with sufficient growth and the average colony diameter was 50 mm. Conclusion: The results of the present study demonstrate that there is a certain level of morphological diversity such as mycelial growth rate and colony characters like color, surface structure and shape exists among isolates of MoO.