Impacts of eco-friendly treatments on managing Alternaria blight disease and enhancing yield attributes of mustard

Abstract

The antifungal effects of some botanical extracts and the antagonistic effects of Trichoderma asperellum isolates against Alternaria brassicicola, the causative agent of Alternaria blight of mustard was evaluated in this study on November 2021 to February 2022 at Bangladesh Agricultural University, Mymensingh. A total of 18 plant extracts and 18 Trichoderma isolates were used to evaluate their effectiveness in inhibiting A. brassicicola mycelial growth. The highest mycelial growth inhibition (93.59 %) was observed with cumin seed and clove seed extracts. Five T. asperellum isolates exhibited 84.13 % growth inhibition of A. brassicicola in in vitro dual culture assays. Following these promising findings, field trials were conducted using the best two botanicals at two different concentrations (1:10 and 1:20) and formulated products of two T. asperellum isolates (BDPMIL-TAN51 and BDPMIL-TAN41) to evaluate their impact on disease incidence and severity of Alternaria blight in the field condition. In field conditions, plants treated with T. asperellum bioformulation demonstrated superior results compared to those treated with botanicals, exhibiting minimal disease incidence and severity (19 % and 18.33 % respectively), while water control plants recorded the highest disease incidence and severity (38 % and 78.33 %) at 54 days after sowing (DAS). Trichoderma asperellum isolate PMIL-TAN51 bioformulation-treated plants displayed the lowest pod infection rate (20 %), whereas control plants presented the highest pod infection rate (66.63 %). Additionally, plots sprayed with Trichoderma bioformulation-treated plants showed better yield-contributing parameters and overall yield compared to those treated with botanicals. According to the results of field evaluation, T. asperellum, as a biocontrol agent, may help in managing Alternaria blight of mustard disease in Bangladesh.