Influence of Silicon on Managing Rice Diseases in the Everglades Agricultural Area

Situation or issue identification: Research in plant disease control generally has focused on resistant cultivars and/or fungicides. However, each of these methods of disease control has its own weaknesses. Development of new races of pathogens may break down genetic resistance. Fungicides are under intense national and international environmental scrutiny for their role as suspected or known ground water contaminants. This project evaluated an alternative approach to disease control by investigating the effect of the element, silicon, found in varying concentrations in plants, on several rice diseases, such as blast. Rationale for research support resources: Silicon is one of the most abundant elements in the earth's crust, and most soils contain considerable quantities of this element; however, repeated cropping can reduce the levels of plant-available silicon to the point that supplemental silicon fertilization is required for maximum production. Low-silicon soils (Oxisols and Ultisols) are typically highly weathered, leached, acidic, and low in base saturation. Organic soils (Histosols) are also considered low-silicon soils. These soil conditions are commonly found in crop producing areas of the Southeastern USA, Brazil, Colombia, and other areas of Latin America, Africa, Asia and Australia. Silicon is known to reduce the severities of blast, brown spot, scald and other rice diseases. Recently, research demonstrated that silicon will enhance host plant resistance and control blast as well as brown spot to the same degree as a fungicide.

Measurable or potential impact in terms of social, economic, and/or environmental factors resulting from expenditure of research support funds: Research in plant disease control generally has focused on resistant cultivars and/or fungicides. However, each of these methods of disease control has its own weaknesses. Development of new races of pathogens may break down genetic resistance. Fungicides are under intense national and international environmental scrutiny for their role as suspected or known ground water contaminants. This project evaluated an alternative approach to disease control by investigating the effect of the element, silicon, found in varying concentrations in plants, on several rice diseases, such as blast. Rationale for research support resources: Silicon is one of the most abundant elements in the earth's crust, and most soils contain considerable quantities of this element; however, repeated cropping can reduce the levels of plant-available silicon to the point that supplemental silicon fertilization is required for maximum production. Low-silicon soils (Oxisols and Ultisols) are typically highly weathered, leached, acidic, and low in base saturation. Organic soils (Histosols) are also considered low-silicon soils. These soil conditions are commonly found in crop producing areas of the Southeastern USA, Brazil, Colombia, and other areas of Latin America, Africa, Asia and Australia. Silicon is known to reduce the severities of blast, brown spot, scald and other rice diseases. Recently, research demonstrated that silicon will enhance host plant resistance and control blast as well as brown spot to the same degree as a fungicide.

Collaborating organizations/agencies and teaching/research/extension partnerships: USAID; USDA-OICD-NCSE; Conservation, Food and Health Foundation, Inc.; Calcium Silicates Corporation; University of Florida; CIAT; IRRI; EMBRAPA and Universidade de Uberlandia, Brazil.

For more information contact: Lawrence E. Datnoff