We have a had a very wet spring. If it turns hot and humid quickly, that could mean fungal outbreaks. Fungus spreads through mycelia, which will “jump” from spot to spot. Mycelia look like spider webs on the lawn that appear prior to damage occurring. If you see these “webs”, then apply  Lawn Fungus Control . Applying
Love Your Soil - at the same time as
Lawn Fungus Control - will help water penetrate the root zone and stay off the leaf, where most fungus occurs.