The journey from the green revolution to the gene revolution has generated many environmental problems including climate change which is one of the biggest threats to human survival. At the dawn of the 21^st century, nanotechnology has emerged as a powerful tool and has been playing a pivotal role in every sphere of life such as biomedical, food and agriculture, electronics, energy, textiles, and cosmetics, among others.

The global population is increasing at a fast rate and according to a United Nations report, by 2050 the population of the world will surge to 9.8 billion (^{Lowry et al., 2019}). For such a vast population we need additional food supply while the existing land has limitations of crop yield. Moreover and moreover, the ever-increasing demand for agri-chemicals has increased the cost on one hand while on the other hand the pathogens and pests have developed resistance to the available fungicides and pesticides.

The biggest challenge before scientists, policymakers, government, and the public at large is how to increase the yield to feed the population by 2050. The researchers are trying to find out the proper solutions to develop nature-based solutions for sustainable agriculture which should be environmental-friendly and be able to feed the hunger of the exploded population globally. It is evident that we need to reduce the high chemical input in agriculture by using nature-based solutions such as plant extracts/ secondary metabolites or integrating them with the low amount of traditionally used chemicals, but another limitation is that natural compounds are not stable and rapidly affected by the change of environmental conditions. In such a situation nanotechnology has come to rescue the environment and crops by using the minimum amount with maximum yield without any chance of resistance development.

Nanotechnology deals with application of nanomaterials in the size range of 1-100 nm which can be synthesized by various physical, chemical, and biological methods. The latter is natural, cost-effective, eco-friendly, simple, more bioactive, biocompatible, and an excellent option for green and sustainable synthesis. The nanomaterials thus generated are less toxic to the aquatic flora and fauna, environment, and humans. However, our knowledge about toxicity is insufficient to draw a convincing conclusion, and therefore, extensive experimentation and analysis are essentially required to unzip the evidence-based clues for the determination of toxicity to have a better understanding of nanomaterials.

These nanomaterials may be inorganic (metal and metal oxides), organic (biodegradable materials dendrimers, liposomes, cyclodextrins, micelle, etc.) or carbon-based (graphene, fullerene, single and multi-walled carbon nanotubes). In this context, more research has been focused on nanomaterials of inorganic origin. These include nanoparticles of metals their oxides and metalloids. Although these materials are bioactive, they are not biodegradable, and therefore, nanoparticles of biodegradable materials such as chitosan and sulfur can be applied so that there is no chance of toxicity.

Usually, plant diseases can be tackled by three major steps: diagnosis of the pathogens, delivery of fungicides/bactericides for slow delivery, and effective control of plant pathogens without migrating to the environment in the general and aquatic environment in particular as well as humans. Further nanomaterials can be applied to treat plant pathogens for the sustainable management of plant diseases.

The early detection of plant diseases is a crucial step in the management of plant pathogens. In light of this, nanosensors can play important role in the detection of plant diseases caused by fungi, bacteria, viruses, phytoplasma, etc. (^{Elmer and White, 2018}). Generally, gold nanoparticle-based nanosensors, immunosensors, and DNA-based sensors are effective for the rapid detection of plant disease. After the detection of the diseases nanomaterials such as nanoparticles, liposome, niosomes, hydrogels or their hybrids can be used for the slow delivery of microbicides against pathogens. For the agri-chemical delivery, encapsulation of nanoparticles with fungicides is fundamentally required to avoid sudden delivery of these microbicides in order to protect against the harmful effect on the environment and humans.

There are ample opportunities for the sustainable use of nanomaterials in agriculture for bumper production of crops avoiding toxicity. Some of the nanomaterials can be used for dual purposes: for the management of plant pathogens (^{Avila-Quezada et al., 2022}a), and also as essential elements for crops (^{Avila-Quezada et al., 2022}b). Nanotechnology-based crop protection also promotes crop yields and the sanctity of the environment can also be maintained. Eventually, it is sure that 21^st century will be governed by a nanobiotechnology-based revolution for sustainable and climate-friendly agriculture without jeopardizing the existence of living beings. However, before its application and commercialization many ethical issues, benefits, and risks should be addressed.