This paper reviews the threat of citrus pathogens during citrus production, with a focus
on two pre-harvest diseases, citrus leaf spot, caused by Alternaria alternata (Fr.) Keissl. (1912) and
brown rot, caused by Phytophthora citrophthora (R.E. Sm. and E.H. Sm.) Leonian, (1906) as well
as green and blue mold post-harvest disease, caused by Penicillium digitatum (Pers.) Sacc. and P.
italicum Wehmer, (1894), respectively. Furthermore, it reviews the role of soluble silicon, Si nutrition
in biotic stress mitigation and potential mitigation mechanisms. Previous studies on the use of Si
fertilizers have focused on high accumulator Si crops. These have demonstrated the potential of Si to
reduce the occurrence of biotic stresses, which takes place through both physical and biochemical
mechanisms. However, few studies have demonstrated the potential of Si to mitigate biotic stress in
citrus, or the mechanisms involved. There is a clear need for studies on the impact of Si on various
stress biochemical pathways in plants generally, and specifically for citrus due to the huge loss
caused by pre- and post-harvest pathogens. This will assist in deepening our understanding of the
pathophysiology which is essential to develop resistant cultivars.