Fall Mortality of the Boll Weevil 1 in Fallen Cotton Squares, with Emphasis on Parasite-Induced Mortality 2

Abstract

Studies were conducted in the northern Texas rolling plains from mid-September to early November 1977 to 1979 to determine the amount of fall boll weevil, Anthonomus grandis grandis Boheman, mortality occurring in cotton squares. Apparent and real mortalities were determined for the immature boll weevil stages—egg to 1st instar, 2nd to 3rd instar, pupa, and teneral adult—for each weekly field-collected cohort. Total real boll weevil mortality increased from 40 to 70% in early October to 100% by late October each year. Parasites caused a significant amount of indispensable boll weevil mortality during early October, but parasitization was not high enough throughout the fall to effectively control the boll weevil.