I have never seen evidence for any bass spawning later than early July. Cessation of RES breeding each year seems more nutritional in nature as I can get year round breeding with them like for bluegill when properly fed indoors. Stoppage of RES breeding seems to start about time of year their diet splits of from what BG consumes. In culture setting I can get later RES spawns where plankton blooms are really strong and forage not limiting for adults.

Aquaculture
Cooperative Research / Extension
Lincoln University of Missouri