Malathion ulv (ultra low volume) is the main insecticide and ultra low volume is the application technology used by the Boll Weevil Eradication Programs on cotton in the United States. This study compares 12 oz. to 16 oz. per acre of Fyfanon ULV (95% a.i. malathion) under actual Program conditions in Hidalgo County Texas. Five pairs of fields (38 acres/field) were selected on a large cotton farm. One of each pair was sprayed by aerial application with 12 oz./acre and the other with 16 oz./acre. Leaf samples were collected from each field and boll weevils were held on these leaves in petri dishes for 48 hours. The first two applications were seven days apart starting shortly after the first square stage of cotton. These leaf samples were collected and tested with boll weevils every other day including 8 and 11 days after the 2nd application. Five, later, applications had leaf samples collected only on the application day. Cotton plants were individually examined for the whole growing season in both treatments. Fruiting records and insect counts were made. No significant difference was found in field infestations between the two rates of malathion ulv or in boll weevil control.