An increasing global population, decreasing amount of arable land available for crop production in the United States, and an increased global demand for protein in the human diet encourage crop and livestock producers to seek solutions to improve the efficiency of producing large crop yields. Corn silage is one of the most commonly used forages included in dairy diets in the United States. For producers, feed costs are often the most expensive part of the operating budget. Corn yield losses may increase the cost of feed and limit herd size. The complex interaction of fungi and corn plants in the field threaten yields, decreasing the efficiency of food production and, also, the nutritive quality of feedstuffs for ruminants. By metabolizing sugar compounds within the plant cell, fungal infections on corn plants reduce the nutritional contents available for ruminant diets. Applications of fungicides can aid in protecting corn plants from fungal infection, therefore, limiting yield losses and increasing the nutritive quality of the plant material. The field of knowledge of feeding ruminants corn silage from corn treated with foliar fungicide is still narrow, but findings from previous research highlight the negatives of making and feeding silage from diseased corn plants. This presentation will summarize the knowledge available on fungi and plant relationship, limiting plant infection by applying fungicide, and how corn silage from corn with fungicide application affects dairy cow performance. It is concluded fungicide application on corn used to make corn silage for dairy cows may improve the nutritional composition of the feedstuff, as defined by increases in milk components and feed conversion, reductions in fiber concentrations, and improvements in ruminal digestibility.