COTMAN is a cotton expert system that among other things calculates heat units from cutout which aids in timing insecticide and crop termination. This study evaluated COTMAN rules for both seasonal and physiological cutout fields in scheduling crop termination in the Texas High Plains. COTMAN predicted crop termination satisfactorily for both physiological and seasonal cutout fields in the central and southern areas of the High Plains. The dates set for seasonal cutout in the northern area based on a 30-year weather database were not realistic and would have significantly reduced yield compared to terminating the crop at NACB (nodes above cracked boll) = 4. The seasonal cutout dates typically allow for only two weeks of blooming and would not allow for the irrigated lint yields typically observed for the northern area. Based on tests conducted in 2000, COTMAN rules for insecticide termination for late-season boll weevil management do not adequately address situations where boll weevil infestations are severe. Grower control programs are typically insufficient to minimize infestations prior to the nominal termination point of 350 heat units past cutout.