Biofumigation is the suppression of soil born pests and diseases through the use of plants that produce inhibitory chemicals, also known as secondary metabolites. In most cases these biofumigant plants are chopped and incorporated into the soil so they can release their inhibitory chemicals. Mustard is a well understood biofumigant. Its biofumigation properties have been studied for a number of years and scientists have developed a method to fully use these properties.