Efficacy of Plant Extracts on Morphology and Cultural Characteristics of <i>Bipolaris sorokiniana</i>, Causing Black Point Disease of Wheat in Bangladesh

Black point of wheat caused by Bipolaris sorokiniana (Bs) is very destructive disease of wheat in Bangladesh and all over the world. The symptoms of diseases caused by Bipolaris sorokiniana can vary depending on the host plant and environmental conditions. The conidia of Bs germinate from two poles, which differ physiologically as indicated by the rate, growth character, of length, breadth and number of septa on different media. The aim of this study was to evaluate the efficacy of selected plant extracts on the morphology and cultural characteristics of the fungus Bipolaris sorokiniana causing black point disease in wheat crops in Bangladesh. The efficacy of fifteen plant extracts on the growth and characteristics of Bs was conducted in vitro in 2019-2020. The treatments were: Untreated control, T1—Black berry Leaves, T2—Guava Leaves, T3—Lantena camera leaves, T4—Eucalyptus Leaves, T5— Turmeric Leaves, T6—Khoksha Leaves, T7—Papaya leaves, T8-Gurlic Bulb, T9—Chili dust, T10—Nigella seeds, T11—Turmeric dust, T12—Cloves, T13— Bohera fruits, T14—Black pepper and T15—Neem leaves. After 15 days of inoculation of Bipolaris sorokiniana, colony color and shapes were Gerrish blackish, greenish blackish, greyish blackish and shapes were round or irregular. In our study, conidia color was dark brown to light brown, conidiophore color was brown, dark brown, grayish brown, dark olivaceous, light brown and conidia shapes were elliptical, oblong or slightly curved. The septation of conidia was 2 - 5 and highest septation was seen in T4 and T14 treatments. The highest conidial length was 17.79 μm recorded in T2 treatment and lowest was 6.62 μm T9 treatment where conidial breath was 8.27 μm in control and lowest was 3.79 μm in T8 treatment. Mycelial growth rate of Bipolaris sorokiniana was different in different treatments in different days after inoculation (DAI) where at 7 DAI, % reduction of mycelial growth over control was highest in Bohera and Neem Leaves treatments respectively.