<i>In Vitro</i> Efficacy Assessment of Botanical Extracts against <i>Botrytis gladiolorum</i> Causing Gladiolus Leaf Blight

An experiment was conducted at the Mycology laboratory, Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh to find out the efficacy of selected botanical extracts against Botrytis gladiolorum (Bg) causing gladiolus leaf blight. Infected leaves samples were collected from gladiolus farmers’ field and brought to the laboratory for study. Ten selected botanicals were used against the colony growth of (Bg). The botanicals were Mehendi, Chrysanthemum, Basil (Tulsi), Onion, Neem, Bael, Arjuna, Garlic, Aloevera (Ghritkumary) and Turmeric. Botanical extracts were applied at the rate of 5%, 10% and 20%. The radial mycelia growth was found minimum (11.60 mm) in garlic extract treated plate at the dose of 5% at 5 DAI, which was statistically similar with turmeric extract treated (14.00 mm) plate and the inhibition of growth was 60% and 51.72%, respectively. Similar trend was found at 10 DAI and 15 DAI. At 15 DAI, garlic and turmeric extract gave the best result against Bg, which was statistically similar with onion (50.07% inhibition) and mehendi (49.93%). All botanicals showed significantly different results over control and found effective in reducing the mycelial growth at the dose of 10%. At 5 DAI, no radial mycelia growth was found in garlic treated plate, which was statistically similar with onion treated plate, means that the inhibition of growth was 100%. Similar trend was also found at 10 DAI, and 15 DAI but at 15 DAI, onion (30.20 mm) gave the statistically similar results with Garlic (30.10 mm) and the mycelia growth inhibition was (57.70%) and (57.84%), respectively. In case of 20% dose, garlic extract showed the best result at 5 DAI and the radial mycelia growth was found minimum (00.00 mm) which was statistically similar with onion extract treated (00.00 mm) plate and turmeric extract treated plate. The inhibition of growth was 100%. At 15 DAI, the inhibition of fungal growth was found (73.74%), (71.23%) and (66.90%), respectively with treated by turmeric (18.80 mm), garlic (20.60 mm) and onion (23.70 mm).