Seems like Doxy might be a better choice for the fall especially the way the seasons go in Massachusetts. However, if you just got a bite or diagnosed, Doxy or Tetra is a good choice and should start to kick the crud out of what ever is there. May take awhile. On the other hand it might not do anything. As you can see my answer is varied, just like Lyme.
The dollar spot fungus survives unfavorable temperature and moisture conditions in plant tissue and thatch as dormant, compact masses of mycelium, called sclerotia. Low nitrogen and potassium levels in the soil have been reported to increase the severity of dollar spot. Some rather severe outbreaks of dollar spot have been brought under control by the application of soluble nitrogen fertilizer. However, the beneficial effect of nitrogen is thought to be due to rapid recovery of the grass during periods of reduced disease activity.
However, in most cases, adequate fertilization (without over-fertilization) can help your grass outgrow dollar spot. A TruGreen expert can help you decide how to tackle the problem so your turf recovers to be the lawn you love once again. To protect against or identify dollar spot lawn disease, call 866.688.6722. You can also browse our website at TruGreen.com to find out how to protect your yard year-round with industry-leading lawn disease control.