Laid Bermuda sod in May. Sod did great in following weeks. Plenty of rain. Now it's June and temps of 95 in NC. I irrigate regularly. Sod is fading to whitish brownish in one corner. Not seeing it anywhere else. Is this disease or just heat stress. Help!
It could be just heat stress. This is assuming the soil bed was adequately prepped and loosened to prevent compaction and ensure good soil/root contact. If the location holds standing water or the roots are unable to penetrate and grow into the native soil due to compaction it could also cause large patches to die, not uncommon. To prevent drought stress and disease, water only early morning. Watering in the afternoon and evening favors development of turf diseases like brown patch. Here is a link to diseases of warm-season grasses https://content.ces.ncsu.edu/diseases-of-warm-season-grasses
You may want to contact your county's Cooperative Extension office and request a site visit to determine if disease is present. They may suggest sending a sample the Plant Disease and Insect Clinic in Raleigh for a firm diagnosis. Another suggestion is not to over-fertilize new sod as vigor and drought stress also favor disease development on new growth. Some of these cultural practices should help. Here is a lawn maintenance calendar for bermudagrass. https://content.ces.ncsu.edu/bermudagrass-lawn-maintenance-calendar
Hope this some of these tips will help your turf get started in the right direction.