Fall mortality of the boll weevil in fallen cotton squares, with emphasis on parasite-induced mortality.
Studies were conducted in the northern Texas rolling plains from mid-September to early November in 1977-79 to determine the mortality of Anthonomus grandis Boh. in cotton squares. Apparent and real mortalities were determined for the immature stages, egg to 1st instar, 2nd to 3rd instar, pupa and teneral adult, for each weekly field-collected cohort. Total real A. grandis mortality increased from 40 to 70% in early October to 100% by late October each year. Parasites caused a significant amount of indispensable A. grandis mortality during early October, but parasitisation was not high enough throughout the autumn to effectively control A. grandis.