‘The breakthrough came from the study of plant immune systems which, in healthy plants, produce an array of compounds that are toxic to intruders. “The immune response in plants is dependent on well-balanced nutrition,” Kempf concluded, “in much the same way as our own immune system.” Modern agriculture uses fertilizer specifically to increase yields, he added, with little awareness of the nutritional needs of other organic functions. Through plant sap analysis, Kempf has been able to discover deficiencies in important trace minerals which he can then introduce into the soil. With plants able to defend themselves, pesticides can be avoided, allowing the natural predators of pests to flourish.’