The HR is triggered by the plant when it recognizes an insect. The identification of a pathogen typically occurs when avirulence geneproducts, secreted by a pathogen, bind to, or indirectly interact with the product of a plant resistance (R) gene (gene for gene model). R genes are highly polymorphic, and many plants produce several different types of R gene products, enabling them to recognize virulence products produced by many different pathogens