ABSTRACT
Vegetables are essential component in nutritional security and economic feasibility. Plant diseases constitute the most important problem in the production of vegetable crops as well as in its storage and processing. Farmers face serious economical yield losses both in terms of quality and quantity of these valuable vegetables crops due to several diseases which are caused by different plant pathogens such as fungi, bacteria, virus, viroid, phanerogamic parasitic plants, and nematodes. In order to overcome this pathogen attack, an appropriate management strategy should be planned against each class of pathogens. To develop proficient management ways against each particular plant pathogen, it is essential to understand their mode of mechanism of infection process in host plants. Infection is the process where pathogens derive nutrients from susceptible host plants by establishing contact with susceptible cells of the host. But, for establishing successful infection inside the host plants by plant pathogens, they must be able to make their own way into the plant systems for deriving nutrients from the host plant and also they must be able to neutralize the defense reactions of the host plant. In this chapter, an effort for simple understanding of various mechanism of 272infection process in each class of pathogens was made with special reference to only vegetable crops.
