Diseases can develop and spread rapidly when grass remains moist overnight. After seedlings emerge, light applications of nitrogen will help produce a dense, healthy stand of grass. Very low rates of soluble nitrogen, such as 2 to 4 ozs. Seedling diseases such as Pythium and brownpatch must be controlled to maintain a thick, healthy stand of winter grasses. Application of a preplant fungicide and the use of treated seed will go a long way toward producing a disease-free turf.
Diseases are much more effectively controlled on a preventative rather than a curative basis.
Once a disease becomes a problem it can set overseeded grasses back several weeks. Strict attention must be given to spray schedules for disease prevention for the first several weeks after planting. Where overseeded fields are covered with tarps during wet conditions, a fungicide such as Subdue or Aliette must be applied before covering to reduce Pythium. Broadleaf weeds such as lawn burweed, chickweed and clover can be controlled after winter grasses are established. Products such as Trimec, Weedone DPC, Turflon II Amine and Confront can be used if label directions are followed.