Nitrated fly ash inhibits root-knot nematode and alleviates biotic stress in beetroot: A novel approach towards soil friendly nematode management

Abstract

Due to the toxic effects of chemical pesticides on the beneficial soil microbiome, alternative ecofriendly tactics are required for sustainable disease management in crops. To find a cost-effective and comparatively safe management practice, we investigated a novel approach by evaluating the waste fly ash modified as nitrated fly ash to control a notorious pest, Meloidogyne enterolobii, which causes considerable losses to beetroot through root-knot disease. Molecular characterization through SSU rRNA confirmed the identification of the pathogen M. enterolobii, which significantly hampers plant growth, pigment content, and yield of beetroot plants. However, applying optimum nitrated fly ash (15 % fly ash + 150 kg/ha N) significantly reduced disease severity significantly and substantially improved the plant biomass, biochemical attributes, and yield of beetroot plants. Furthermore, scanning electron microscopy revealed a significant improvement in nematode stress-induced stomatal closure with the application of nitrated fly ash at 15 % fly ash +150 kg/ha nitrogen amendment to the soil. The nematicidal activities of fly ash were also confirmed through in vitro experiments combined with cell viability methods. Our results suggest that exploiting nitrated fly ash at optimum concentrations can be a promising approach to manage this waste product and control root-knot nematodes (RKNs) in an eco-friendly manner.