Water infrequently and deeply during early morning hours. Watering in the afternoon or late evening is problematic. Grass that is freshly fertilized is particularly susceptible to disease. Fertilize only as recommended for your variety of grass, at the right time and in the proper amount.
When reseeding, choose varieties that are resistant to fungal disease. Plant a blend of resistant grasses to reduce the chance of loss from disease in the future. For a thorough discussion of lawn care in Texas go to http://aggie-turf.tamu.edu.