Diflubenzuron (Dimilin), applied at a rate of 1 oz. active material per acre in 112 gallon of cottonseed oil, was effective in reducing egg hatch of native populations of boll weevils infesting commercially grown cotton. Dimilin was aerially applied over approximately 700 acres at 7 day intervals and over 600 acres at 10 day intervals. Five plots of 5-6 acres each from the two treatments and from an area where no Dimilin was applied were sampled weekly for egg hatch, numbers of adults per acre and numbers of adults captured in pheromone-baited traps placed around the fields. Hatch did not exceed 859 in the 7-day interval fields and was as low as 309. Results of the trap data indicated that the native population present in the 10-day interval fields at the start of the test was much lower than that present in the control or the 7-day interval fields. Very little data was collected from the 10-day fields, but egg hatch did not exceed 509. The number of adults per acre in the 7-day interval fields peaked at about 40% that of the controls and in the 10-day interval fields about 5% that of the controls.