Eradication efforts to rid the United States cotton producing areas of the boll weevil (Anthonomous grandis grandis) Boheman are underway as all areas have either entered or have agreed to enter eradication. The key component of the eradication is the application of ulv malathion. It is critically important that the susceptibility of the boll weevil to malathion is clearly understood for completion of eradication. Any explanation in variation in mortality response from laboratory assays will help define expected susceptibility and delineate it from true resistance. We conducted a series of laboratory assays that determined the roll of age, sex, weight and physiological condition on the boll weevils response to malathion.