Originally Posted by LawnMowerKing10
Tall Fescue. I am in Northern Virginia. My lawn is a little larger than half an acre I believe.
Now that we know what we are dealing with; Make sure that your watering practices are in place and not watering before the lawn can dry off. Have you put down any high Nitrogen fertilize as Riggs pointed out.
You've got to be able to apply the fungicide properly. I use 4 gallons of water per 1000sq ft of turf. So you have got to have proper equipment to do that. A fungicide such as Daconil [Chlorothalonil] (Manicure from John Deere Landscapes) is a folliar type and needs to dry on the leaves along with a good surfactant (MSO) to open the grass blades to accept the Daconil. Along with the Daconil a good systemic non strobin fungicide is needed. the Strobins (class 13 I think) are not effective on brown patch. Cleary's 3336[Thiophanate] would be the first to use. If the fungus is really active, reapply in 14 days. Mix both of these and apply. Remember to let it dry and then irrigate the lawn in about 1-2 days after. Do not mow for three days after the application. Hold your fertilize until later when it is cool. If you don't have the capability of applying enough to really get the fungicide down to the roots or covering the plant crown, I would hire a pro in your area that has the equipment. He might be a better bargain than buying these expensive chemicals. However, I would insist on knowing what he is applying and how much he is putting down. Some of these so-called pros are flying by the seat of their pants and only hoping for results. Check to see if he is a licensed pro. We have some good people on here that might be in your area. Isn't Fairfax to the west of DC?