Effects of plant extracts on controlling wheat blast disease caused by Magnaporthe oryzae Pathotype triticum in Bangladesh

The present research work was conducted to evaluate the efficacy of twelve plant extracts viz. Neem (Azadirachta indica), Bishkatali(Polygonum hydropiper), Nishinda (Vitex negundu), Allamonda (Allamanda cathertica), Acasia (Acacia auriculiformis), Tulsi (Ocientific tenuiflorum), Mehendi (Lmetawsonia alba), Datura (Datura metel), Bishkochu (Alocasia fornicate), Black cumin (Nigella sativa), Garlic (Allium sativum), Mehogoni (Swietenia macrophylla) @ 1:10 along with two fungicides Provax and Nativo @ 0.2% as check against Magnaporthe oryzae Pathotype triticum which is responsible for wheat blast disease at Department of Plant Pathology, Bangladesh Agricultural University and Plant Pathology Division, Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh-2202. This experiment was conducted in two phases viz. laboratory and pot experiment. In the laboratory experiment, the efficacies of plant extracts were evaluated by the measurement of percent inhibition of radial mycelial growth of M. oryzae Pathptype triticum. The highest percentage of mycelial inhibition (93.75%) was recorded in case of four plant extracts namely Tulsi, Mehendi, Datura and Garlic followed by Black cumin seed extracts (90%) at 10 days after inoculation, where as Allamonda leaf extract showed lowest percentage of mycelial growth inhibition (7.5%). On the basis of in vitro test five plant extracts were selected to conduct pot experiment to evaluate the disease incidence and severity, and some yield contributing parameters in treated and control plants. Minimum percentage of disease incidence and severity were recorded in case of Garlic clove extract (16.28 and 3.5) treated plants and the Mehendi leaf extract treated plants showed highest % of disease incidence and severity (66.0% and 68.0%). Garlic clove extracts also showed best performance for yield contributing parameters namely ear length (9.20 cm), number of ear/pot (13.25), number of healthy ear/pot (13.0), number of total and healthy spikelets/ear (34.20 and 33.40),number of total and healthy grains/ear (23.00 and 21.80) and weight of 1000 total and healthy grains/pot (56 and 52 gm) followed by Black cumin, whereas Mehendi leaf extract treated plants showed lowest value for all the yield contributing parameters among the plant extracts used in this experiment. Both in in vito and pot experiment Garlic extract showed best performance and it might be used for the eco-friendly management of blast disease and increase the yield of wheat. [Fundam Appl Agric 2018; 3(2.000): 422-433]