Plant diseases represent one of the key factors limiting crop yields which still pose the greatest danger to global agriculture and significantly lower crop yields globally, which has a negative impact on food supply. To stop dispersion disease and to promote efficient control techniques, crop health monitoring depends heavily on the correct and early noticing of plant pathogenic microbes. Various techniques have been utilized to diagnose crop diseases, such as visual examination of symptoms, serological tests, and detection of pathogens based on DNA. To tackle these challenges, nanotechnology, particularly nanobiosensors, has emerged as a promising tool for diagnosing plant diseases and pathogens, assessing microbial infections, managing diseases, and ultimately improving productivity. Moreover, they are labour-intensive, require expensive equipment, produce inaccurate findings from the cross contamination, and needs professional experts in the field. Nanobiosensor-based technology introduces a novel approach to plant disease diagnostics by offering non-destructive, minimally invasive, affordable, and user-friendly systems. It enhances detection limit, sensitivity, and specificity, enabling efficient on-site pathogen detection. This chapter provides a brief outline of the use of nano integrated nanobiosensors in plant pathogen diagnosis.