The best way to get rid of red thread is proper fertilization, mowing, and
irrigation of the turf. There are plenty of fungicides available that will
control and prevent it, but they will not cure it completley. You can use any
of the following:

Thiophanate-methyl- sold as clearys 3336, also as scotts lawn fungus control.

Mancozeb- cleary's protect or mancozeb flowable.

Propiconazole- also known as banner maxx. also sold as simply "garden
fungicide" by ferti-lome.

Again, chemicals are your last resort, and proer cultural practices are always
the best way to keep fungus away.

Toad