**1. Introduction**

Fungal pathogenic diseases are responsible for yield losses in staple calorie and commercial commodity crops posing a major threat to crop productivity globally. The yield gaps have enhanced due to the emergence of new fungal crop pathogens [1] as a consequence of intensive monoculture and environment variations arising due to aberrant climatic conditions [2,3]. Therefore, the agronomic interventions, land management practices, and climate change have been the primary agents that have altered both abiotic and biotic components affecting crop growth and yield [4].

Maize, a versatile cereal-food, feed, and industrial crop, is sensitive to attacks and diseases caused by several fungal pathogens [5]. It is the second-largest considering the area under production and is ranked fourth in productivity among cereals [6] across the globe. Substantial annual yield decreases and depreciation in grain quality in maize are two quantifiable manifestations of the fungal infection and disease [5]. The primary fungal pathogens of maize include the *Macrophomina phaseolina*, *Curvularia lunata* and *Fusarium oxysporum* which cause charcoal rot, leaf spot, and stalk rot diseases respectively in maize. The infected plants are generally treated with anti-fungal compounds or fungicides to curb the spread of the pathogen. However, for continuous monoculture predominated agroecosystems, spraying of these antifungals only provides ephemeral protection to the plants due to the single target site mechanism and the emergence of resistant fungal strains [1]. This necessitates the development of effective analogous antifungals without compromising the ecological and bio-safety aspects.

The present decade has witnessed the emergence and use of nano-scale materials as potent anti-microbials particularly anti-fungal agents. The zinc nanomaterials including the nano-zinc particles possess excellent anti-mycotic properties against a variety of plant fungal pathogens [7–12]. The predominant mechanisms governing the anti-mycotic effect of ZnNPs include the reactive oxygen species enabled stress besides Zn2+-based toxicity occurring due to the formation of these ions on dissolution of ZnNPs in the cell environment [7]. The size of ZnNPs and their crystal chemistry can affect the fungicidal potential as these characteristics alter the ability to trespass the fungal cell wall and membrane structures to elicit ROS response besides varying the dissolution of the ZnNPs within the fungal cell cytoplasm. The anti-fungal activity of ZnNPs have been identified against *Alternaria alternata* [13], *Aspergillus flavus* [14], *Botrytis cinerea* [11,15], *Candida albicans* [16], *Fusarium graminearum* [17], *Fusarium moniliforme* [8], *Fusarium solani* [18], *Penicillium* sp. [19–21], *Penicillium expansum* [22], *Pythium ultimum* and *P. aphanidermatum* [23], *Rhizopus stolonifera* [24] and many more fungal pathogens of plants.

This investigation aims for the wet chemistry-based synthesis of ZnNPs through the use of different (three each) reducing and complexing/capping agents. The generated ZnNPs were characterized through UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), and Fourier transform Infrared Spectroscopy (FT-IRS). These ZnNPs were evaluated for anti-fungal potential against three prominent fungal pathogens of maize *viz.*, *Curvularia lunata, Fusarium oxysporum,* and *Macrophomina phaseolina* in an agar well diffusion assay. The variation in the anti-oxidant potential of these ZnNPs was assessed through scavenging of the DPPH radicals while the genomic DNA degradation potential was determined through a DNA-ZnNPs incubation study followed by agarose gel electrophoresis of the samples.

#### **2. Materials and Methods**
