Although fungus season is still a couple months away, it never hurts to be prepared. In Virginia, the most common Spring/Summer fungus problems can be divided into two groups: Cool season and Warm Season.
Red Thread
Red thread is one of the earlier Spring fungal problems that is very common in our area. It is characterized by small, irregular, reddish/pink areas. Malnourished or acid ridden lawns are more susceptible to this disease. The good news about Red Thread is that it very rarely leaves permanent scarring. Hotter weather ends it reign before it can permanently damage the turf (usually). A preventative broad spectrum fungicide in early April will usually prevent this nusiance.
Dollar Spot
Dollar Spot is a warm season fungus. It is characterized by a small, white blotch. Multiple blotches will appear in clusters. This disease will not permanently damage the lawn. A good soil base usually is a good long term solution to this problem. Organic fertilizers offer the best long term solution. If you want to prevent this fungus, use a fungicide in late April to prevent it.
Brown Patch
Probably the most damaging fungus we see in the area is Brown Patch. This fungus is characterized by 6 to 12 inch rings that die from the inside outward. This fungus is extremely aggressive and destroy a heathy lawn in just a few weeks. This fungus is active during the hottest part of the Summer with high humidity. Prevention is best cure. Applying Fungicide every month from May to August should do the trick.