Replicated experiments were conducted in 2000 and 2001 in the same cotton field to examine the effects of irrigation and nitrogen (N) rates on the time required to terminate insecticide applications. In both years irrigation increased days to reach insecticide termination. In the year 2000, irrigation increased returns above the specified costs of irrigation and insect control but in 2001 irrigation dramatically decreased returns above the insect and irrigation costs. Only in 2001 was N measured. In 2001 increased N decreased returns above the cost of N and insect control numerically under both irrigated and non-irrigated conditions but were significantly different at the P=0.05 level of probability in irrigated plots fertilized with 180 lb/A N.