Lham Dorjee

Copper nanoparticles are increasingly being explored as a sustainable alternative to conventional fungicides for controlling plant pathogens, offering enhanced efficacy and reduced environmental toxicity. This study investigated the antifungal mechanism of essential oil-grafted copper nanoparticles (EGCuNPs) using scanning electron microscopy against Sclerotium rolfsii, Fusarium verticillioides, and Rhizoctonia solani. Morphological and molecular characterization confirmed the identity of the pathogens, with ITS sequencing validating the identity of R. solani (GenBank accession OR251925). In vitro assays at ED50 concentrations of EGCuNPs revealed significant growth inhibition of all three fungi. Scanning electron microscopy (SEM) demonstrated disruption of hyphae and spores, confirming the potential antifungal activity of EGCuNPs. While S. rolfsii exhibited some tolerance, EGCuNPs caused significant damage to hyphae. The study demonstrates the antifungal mechanism of EGCuNPs, proving its potential as a next-generation fungicide. Further research should address molecular mechanisms through transcriptomics and long-term ecological impacts of repeated application of copper-based nano-formulations.

Powdery mildew, caused by the fungus Podosphaera fusca, poses a significant threat to global cucurbit cultivation. This report presents a noteworthy observation with potential implications for managing the prevalent biotic stress in cucumber crops. Our research unveils the active feeding behaviour of the earwig species Forficula auricularia on P. fusca, highlighting its potential as a promising natural biocontrol agent. Molecular identification techniques, resulting in accession number OQ102947, unequivocally confirmed the species as F. auricularia. While this discovery is promising, further studies are crucial to evaluate the biological control efficiency of F. auricularia against P. fusca in cucurbit crops.

Since time immemorial organic amendments have been an important strategy for improving soil fertility and suppressing a wide range of soil-borne pathogens. Biochar, a charcoal-like amendment has true potential in managing phytopathogens with an eco-friendly approach. It is produced by subjecting plant materials and agricultural waste to high temperatures of around 900°C in limited oxygen conditions. Biochar is considered to be an excellent carbon sequester and has an undeniably imperative role in improving soil properties. Biochar has innumerable applications in the remediation of environmental pollutants by immobilizing heavy metals such as Cadmium and Arsenic and degradation of dyes and pesticides. One of the most significant advantages of biochar in addition to mitigating environmental pollution is effectively managing plant pathogens by altering soil physical and chemical properties and promoting antagonistic microorganisms. Biochar directly suppresses plant pathogens by priming plant defense mechanisms. For instance, sugarcane bagasse biochar remediates Cd from contaminated soil, and citrus wood biochar induces systemic resistance against Botrytis cinerea in host-Lycopersicon esculentum, Capsicum annuum L. cv. Maccabi and Fragaria ananassa. Nevertheless, it is essential to acknowledge its limitations, such as the potential to absorb and enhance the residual activity of harmful chemicals. Further research is needed to develop a deeper understanding of biochar’s properties and mechanisms for more effective results. Advanced techniques like meta-transcriptomics and metaproteomics hold the potential to provide invaluable insights into this field. The review provides a comprehensive overview of current information regarding biochar, covering its production techniques and highlighting its agricultural benefits, with a particular focus on its role in plant disease management. Furthermore, the associated risks and concerns are also discussed.