For very destructive diseases such as Pythium the threshold for that particular disease would be zero. The approach described above for dollar spot can also be used for weeds. Again, thresholds should be established for all turf pests and for all catagories of turf. The ultimate goal is to use these thresholds to make decisions on whether or not to spray, so it is important that thresholds are established. Don't forget to consider the conditions of the turf.
Weak turf can tolerate fewer pests than healthy vigorous turf.
Resources - Gather up literature on turf pest biology, life cycles, identifying features and damage symptoms. This chart will tell you which diseases are likely to occur at any time during the season. This will also alert scouts about what to look for at any particular time during the season. This will help them identify insects they find in the field. In addition, slide sets and videos are also useful for training staff.