Abstract: The present invention includes the characterization of the major salivary protein or enzyme of the corn earworm Helicoverpa zea for triggering resistance to bacterial blight and frogeye leafspot in soybeans and for triggering resistance to insects in tomatoes. The invention includes an enzyme or a novel protein secreted from the salivary glands of certain insects including the saliva of species belonging to the order Hymenoptera and Lepidoptera. The regurgitant of Helocoverpa zea obtained from the functional salivary glands contains a protein that possesses glucose oxidase activity. The amino acid sequence of the protein is unique and when the protein is applied to plants, it triggers disease and insect resistance systematically. The physical and kinetic attributes of the enzyme are a pH of 7.0, a pI of 4.4 and a molecular weight of 88 kd. The km and Vmax of the enzyme for glucose is 26.9 mmol and 26.7 &mgr;mol min−1 mg−1, respectively.