You may often think of cover crops as a way to prevent erosion and add diversity to your rotation, but they have another less obvious but very tangible benefit – they can create a physical barrier against soil insects and diseases. Foliar diseases in corn can be greatly reduced where cover crops and no-till/reduced tillage practices are used. Not only does crop rotation break up disease pressure, but a physical residue barrier left on the soil surface from a cover crop also blocks the ability of fungal spores to splash up from soil with raindrop impact to make contact with the leaves. This is the primary early-season vector for fungal diseases like Northern Corn Leaf Blight that overwinter in soil and corn plant residue. Spores are also blown in by wind, but this is usually later in the season when there is less potential to impact yield.