Foliar Diseases Alter Carbohydrate and Protein Levels in Leaves of Alfalfa and Orchardgrass

Abstract

The percentage of crude protein (CP), total nonstructural carbohydrate (TNC) and dry matter (DM) levels were investigated with alfalfa [Medicago sativa] and orchardgrass [Dactylis glomerata] infected with Phoma medicaginis and Stagonospora arenaria, respectively. In alfalfa, the TNC and CP were decreased and the DM increased when the infection severity level was > 80%. Crude protein was significantly reduced in orchardgrass leaves at the 20% disease level. TNC at the 50% disease level, and DM was increased at all levels of disease. Crude protein was higher in healthy new growth from diseased alfalfa plants than CP in regrowth from healthy plants. In bulk-harvested orchardgrass the TNC percentage, TNC yield, and DM yield were reduced. Foliar diseases reduced the TNC and CP of both alfalfa and orchardgrass leaf tissues sufficiently to adversely affect the quality of the forage and that the loss of TNC was greater than that of CP.