Infectious diseases caused by microorganisms for getting their nutrition, where the plant called the host and pathogenic organism called a pathogen or parasite, such as fungi, bacteria, virus and nematodes e.g. fungal wilts, bacterial leaf blight, streak mosaic virus and nematode root-knot diseases, respectively. These species can survive for many years in the absence of a host plant by forming persistent structures such as microsclerotia. Therefore, the dependence on a single method or a single chemical for controlling plant pathogens should be avoided because of high cost; development of...