Zeizite Cu is a physiological inducer fertiliser based on potassium phosphite with a double function over crops. It provides the source of phosphorus and potassium, as well as copper. Furthermore, the phosphorus is presented as phosphite, which improves phytoalexins synthesis with anti-fungal properties by phosphite ion. As a kind of liquid fertiliser, copper participates in the chlorophyll synthesis, lignin synthesis and in the cellular respiration of the plants. So, the copper phosphite solution is used as bactericide, fungicide and antivirus for plant health.