The study evaluated age-specific mortality of heliothine larvae on flower buds (squares) of conventional non-transgenic and VipCOT cotton cultivars. Cotton flower buds were infested with a single (2-d, 4-d, 6-d, or 8-d-old) heliothine larva. The larvae were inspected every 2 d, offered additional squares, and survival of each larva was recorded. Cumulative larval and pupal survival, complete larval stadia, and 1-d-old pupal weight was recorded for each larva.