Processing gin trash through flat-blade centrifugal fans to kill pink-bollworm larvae (pectinophora gossypiella Saunders) has long been an accepted method of control. Specifications for the operation of pink bollworm fans from 48.3 to 82.6 cm (19 to 32.5 in.) diameter are part of USDA, APHIS regulations. Gins are now being built that use pink-bollworm fans up to 107.3 cm (42.24 in.) in diameter. It was necessary to determine pink-bollworm mortality using the larger diameter fans. Results indicated that fan tip speeds above 3,962 m/min (13,000 ft/min) resulted in 100% mortality of pink-bollworm larvae contained in green bolls regardless of fan wheel diameter.