Background Infectious diseases are a leading cause of death in humans, animals, and plants globally. Pathogen infections can reduce food production and endanger biodiversity. Viruses, bacteria, and fungi are therefore scientifically and economically important in food production. Even outbreaks of a pathogen infection in plants or animals have direct consequences for the food chain and human health. Scope and approach Microorganisms such as bacteria, fungi and virus invade plant cells and utilize the host resources for their survival disturbing the plant or animal metabolism leading to diseases. Advance diagnosis and effective detection of pathogens, infectious diseases, and other parameters affecting the health of animals and plants in agro-defense will assist in reducing financial costs, increasing food production, and improving the global economy. In this article, common pathogens and infectious diseases in animals and plants, along with the point-of-care technologies that address them, are reviewed. Key findings and conclusions The synthesis and discovery of novel nanomaterials and the fabrication of highly specific and sensitive biosensors have expanded the scope for effective agro-defense biosensors. Progress in biosensor development and the existing challenges are reviewed to provide future directions in this field.