Role of zinc oxide nanoparticles in the management of disease complex of beetroot (Beta vulgaris L.) caused by Pectobacterium betavasculorum, Meloidogyne incognita and Rhizoctonia solani

Abstract

The impact of zinc oxide nanoparticles (ZnO NPs) in 100 and 200 mg L−1 concentrations was examined on the hatching and mortality of M. incognita (Mi) and the growth of P. betavasculorum (Pb) and R. solani (Rs) under in vitro conditions. ZnO NPs inhibited the hatching and caused mortality of 2nd stage juveniles (J2s) of Mi and also inhibited the growth of Pb and Rs. In pot experiments, ZnO NPs in 100 and 200 mg L−1 concentrations were delivered as a foliar spray and seed priming for the management of disease complex of beetroot. Foliar spray of ZnO NPs to plants infected with pathogens or un-infected more efficiently improved plant dry mass and physiological and biochemical parameters of beetroot than seed priming. Foliar spray of ZnO NPs at 200 mg L−1 to plants infected with pathogens resulted in the greatest increase in plant dry mass, and physiological and biochemical parameters of beetroot. Seed priming and foliar spray of ZnO NPs caused a reduction in disease indices, nematode population, and root galling. Foliar spray of ZnO NPs at 200 mg L−1 caused the maximum reduction in disease indices, nematode multiplication, and root galling. The inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that ZnO NPs were accumulated in shoots and roots of both infected and uninfected plants independent of the application methodology. Overall, the findings suggest that ZnO NPs as the foliar spray has the potential for the management of root-knot, soft-rot, and root-rot, disease complex of beetroot.