Impact of pine needle and corn cob pyrolyzed bio-oil on Bipolaris maydis and maize crop yield enhancement

Pine needle and corn cob pyrolysis bio-oil-based formulation (BOBF) was prepared and analyzed for in vitro antifungal activity against five maize fungal pathogens Alternaria spp., Curvularia lunata, Bipolaris maydis, Bipolaris zeicola, and Fusarium spp. that exhibited 100% growth inhibition. The effect of both BOBF at three different concentrations 500 ppm, 1000 ppm and 1500 ppm on B.maydis infected maize crop was analyzed in the field condition. In contrast to pine needle BOBF, corn-cob BOBF was found to have a much lower percent disease index (PDI) in maize crops infested with Maydis leaf blight (MLB).The grain yield of maize was increased by 34% in pine needle BOBF and 44.5% in maize cob BOBF compared to untreated maize crop. GC–MS analysis revealed that both BOBF contains approximately 50% of the phenolic compounds. Plants treated with BOBF showed increased activity in SOD, APX, GPX, GR, and 1,3 glucanase, indicating that pine needle and corn cob BOBF induced antioxidants and pathogenesis-related proteins involved in ROS mediated plant defense. Phytochemical analysis revealed an increase in phenol, flavonoid, antioxidant, and ascorbic acid content at 1500 ppm concentration on day 8. It was concluded that pyrolysed BOBF play a role in the synthesis of secondary metabolites which help the maize plants to combat oxidative stress generated by infestation.