Enhanced disease resistance in Yard-long bean (Vigna unguiculata) against Brown Rust and Fusarium Wilt diseases using Trichoderma and antioxidants

Abstract

Yard-long bean (Vigna unguiculata) is a significant leguminous crop in tropical countries. The vegetable is becoming more and more popular, because of its excellent flavour and high nutritional content. Brown rust and Fusarium wilt disease of yard-long beans caused by Uromyces phaseoli typica and Fusarium oxysporum f. sp. phaseoli are two devastating diseases responsible for maximum yield loss in Bangladesh. The present study was aimed at the bio-control of Brown rust and Fusarium wilt disease as an alternative means of chemical control. For enhancing systemic resistance in yard-long bean plants against Uromyces phaseoli typica and Fusarium oxysporum f. sp. phaseoli as well as for the sustainable and eco-friendly management of Brown rust and Fusarium wilt disease, two previously isolated Trichoderma (T. asperellum and T. harzianum) were used to control these diseases. This study was also concerned with the application of antioxidants; salicylic acid and tartaric acid. In the pot experiment, the triple combination of charcoal-based formulated T. asperellum, salicylic acid (4 mM), and tartaric acid (10 mM) exhibited the highest reduction of Rust incidence (75.02 %) and Rust severity (75.38 %) over control as well as Wilt disease incidence (69.86 %) and Wilt disease severity (80.56 %) over control at 60 days after sowing (DAS). The triple combination of charcoal-based formulated T. asperellum, salicylic acid (4 mM), and tartaric acid (10 mM) resulted in the highest yield in yard long bean (5.3 Kg/plant) compared to other treatments and control. This combination also exhibited the best results in all tested parameters in plant height (199.43 cm), leaf number (60.33), number of pod/plant (84.67) at 90 DAS, and pod length (65.63 cm). Furthermore, this combined application showed maximum total chlorophyll content (151.33 mg/g FW) as well. The study explored the use of charcoal-based formulated T. asperellum, salicylic acid (4 mM), and tartaric acid (10 mM) for the preparation of bio-fertilizer and/or bio-pesticides for the field application to control Brown rust and Fusarium wilt disease of yard-long bean.