A release of 1500 of Catolaccus grandis (Burks) was done in an insecticide free cotton field without detectable boll weevil infestation. Sample stations consisting of infested cotton squares were placed every 30 meters in four directions from the point of release. Parasitism was detected in the first sample (after 3 days of exposure) at 120m North, 90m South, 30m East, and 90m West from the point of release.