Fungus
This is the prime time for fungus to develop. Hot muggy days and warm wet nights are the main cause. If you are watering your lawn be sure it is done early in the morning instead of late at night. This will allow the water to evaporate throughout the morning, while allowing the soil to absorb the water.
Improper mowing heights can also encourage disease and fungus to develop. Keep your mower deck heights between 3 and 3.5 inches. This will help the roots develop deeper into the soil, and the extra height on the grass helps shade out weeds. The best weed defense is a thick healthy lawn.
We are also seeing a little bit of wilt on trees. The super hot days the last few weeks with little water is causing the leaves to curl and wilt a little bit. If you have a newer tree and are seeing this, most likely you need to get some water on it and keep up the watering until the tree starts looking healthy.