Recurrent plant disease problems most often point to a soil problem, so what is the status of your soil?
How much organic matter is in that soil?
How well does that soil drain?
How well does that soil retain moisture?
What is the animal life in your soil?
What does your soil smell like?

Here is a link that might be useful: About Dollar Spot

unfortunately i have had too much experience with fungi over the last 3-4 years. first off, cornmeal does not work on any fungus after systemic fungicide like baking soda is applied because you have eliminated the beneficial fungi for a prolonged period. in addition, first you have to identify the type of fungus and treat with effective fungicide. i have dealt with dollar spot, leaf spot, stripe smut, rust, snow mold and powdery mildew (if it looks like it snowed, you may have powdery mildew). anyhow, cornmeal completely suppressed my dollar spot over the last few years, partially suppressed leaf spot. it does not work against rust or powdery mildew which i successfully spot spray with baking soda (just in a few small shaded areas). Small patches of snow mold were simply raked out and grass grew in fine over these small areas. Stripe smut was worse than ever this summer due to heat and humidity and i had spreading 1-2 foot patches of thinning/brown grass with charcoal gray dust spore clouds when walked on. i broke down and used scotts lawn fungus control a few weeks ago which appears to have suppressed the smut. in summary, cornmeal is affective for some fungi but not for others and once you decide to use systemic, you must wait a few months for cornmeal to again become potentially effective.

Since plant diseases are not a normal thing, jk11, it too sounds like you need to look at your soil to see what the problem is.

i send soil samples off to Umass every 2 years, pH 6.8, nitrogen usually low, K was low, but now normal, P normal, organic content normal, earthworms thriving, i see many when extending beds and doing new plantings. i've added whatever fertilizer Umass recommends after each soil analysis. problems could be soil, environment or culture. my culture includes mowing high (3 in.), 1 in water/week and fertilize 3-4 times per year plus milorganite in july/august. the only times i have issues with fungi is during environmental stressors, and the outbreaks are usually confined to less than 5% of entire lawn - prolonged heat/humidity/rain. in mass it has rained only 1.2 in. in last 2 months, with record breaking heat and humidity (one 10d stretch over 90 degrees), not ideal weather for cool-season mix of kbg/tttf.

How well does your soil drain? What does "organic content normal" mean? How much is in your soil?
Are the UMASS recommended fertilizers synthetic?
Nitrogen levels vary depending on soil temperature which affects soil bacterial activity, but low Potash (K) levels indicate a lack of sufficient organic matter in the soil to hold what you have been applying. Since cool grasses (such as would be grown in Massachusetts) tend to wnat to go dormant in the hot, dry summer weather feeding, even an organic fertilizer is largely a waste of money, time, and energy, applying any ferttilizer 3 to 4 times a year is largely a waste of money, time, and energy.
Keep in mind that the 1 inch of water per week is a starting point and under ideal conditions. If your weather is hot and dry your lawn may need more water, while if the weatjher is cool and wet it may not need any water. Watering a little bit daily (most in ground systems do that) creates good conditions for both "weed" growth and plant diseases. Watering less often but longer, so the water penetrates the soil deeper, makes conditions that cause grasses to root deeper which creates a healthier stand of turf and prevents the "weed" seeds on the soil to get the moisture they need to germinate. Mowing high aids in shading the soil so those "weed" seeds do not get the sunlight needed for germiantion, often, helps reduce soil moisture loss from evaporation because the soil the turf grass is growing in is cooler, can crowd out any "weeds" that might germinate, and provides the grass plants with more leaf to manufacture the nutrients those blades of grass do so the grass sends out more which thickens the stand of grass which shades the soil more to prevent more "weeds" from growing. A good, healthy stand of turf grass is also better able to withstand plant diseases.

soil drains fine, no puddles/pooling even in a few of the lower spots, graded with 10-12" loam pre-hydroseed 4 years ago, organic content between 7.2% or above on all tests (normal 4-10% per umass lab), earthworms and earthworm predators (robins)in abundance, last K and P levels in med-high range. water on average 1" per week, 1 time/week, but during recent heat wave, low rainfall-- increase to 2x per week when grass shown signs of stress (drying/wilting, retained footprints for prolonged time).

Since plant disease of any kind is not normal if plants do have one they are a symptom of a problem, so if you continue to have diseases in your turf you need to look at the why. Synthetic fertilizers are known to contibute to plant disease and is one reason the companies that manufacture them also manufacture the, not environmentally friendly, means of controlling those plant diseases.
However, if everyone around you has a plant disease the cance that your plants will also have that disease increase exponentially and whatever you use to control that disease may not be effective since reinfection will occur as soon as the treatment is over.