Since fungi need a fairly moist environment to live in the presence of a fungi in grasses, would be an indication that the envionment of that grass is too wet. While spreading corn meal, in the spring, might be a short term aid in suppressing that problem the long term solution would be to look at the environment that allows that fungi to grow and fix that.
To establish what any spreader is dropping you need a measured distance to run it over to determine what setting is close to what you want to spread.

If you know you have 1,000 square feet and want to apply 20 pounds of stuff, pour out 20 pounds of stuff, set the spreader to 1/2 of all the way open, and spread until you have used up the 20 pounds. You might find yourself opening the spreader as you go just to make it go faster. Spreaders are not made for organic fertilizers.

Normally the advice is to apply fertilizer once in the late spring and twice in the fall. If you are going after a disease, I would apply every month as soon as it warms up. That might be February or April depending on where you live.