Plant pathogens are a major concern in production of crops as they lead to a great loss of food grains. Although several methods are available to manage the diseases and the chemical-based methods are frequently used, and sometimes indiscriminate use poses serious problems to the environment. It is, therefore, necessary to detect plant pathogens at an early stage in order to control epidemics. Plant pathogens can be detected using conventional methods such as culture-dependent, biochemical and molecular techniques; however, these methods need advanced technical skills and well-equipped laboratory facilities and are not suitable for in situ analysis. Several nanotechnology-based methods are available for plant pathogen detection. Among them, biosensing systems for early detection of the pathogen using nanobiosensor are gaining momentum in field of research on plant pathogen detection. Materials having size ranging from one and one hundred nanometers are known as nanoparticles. These materials have special qualities that can be used to improve agricultural practices. Nanobiosensors are novel integrated systems of biosensors that are made up of a bioreceptor, transducer and a detector on the nano scale size. These nano-inspired biosensors have played a major role in enhancing nature of life through different medical, environmental and quality-control applications globally. Numerous nanobiosensors have been developed, including those for detecting plant infections caused by fungi, viruses, and bacteria. This review will contribute to understanding the basics of biosensors and their accessible biosensor based detecting tools and techniques for plant pathogens.