Growth habits and behavior of cotton plants and bollworms, pink (PBW), spiny (SPW), and the American bollworm (ABW), both separately and as they interact were studied and quantified under field conditions and various dates of planting in Middle Egypt. Accumulated thermal units for bollworm generations (from January 1st) were used to determine the comparable plant growth stages in the common dates of cotton planting. Number, size, and locations of different fruit structures were, also determined and used as indicators for each generation. This method accurately and simply expresses bollworm generations and will help the growers to make the better control decisions and to reduce their reliance on pesticides for bollworm management.