This study was conducted to determine the effects of different irrigation systems on the inundative release of the egg parasitoid Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) against Ostrinia nubilahs Hubner (Lepidoptera: Pyralidae) in the second crop maize in the Cukurova region of Turkey in 1999 and 2000. O. nubilalis, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and T. evanescens were reared in a climatic room under constant temperature of 25 +/- 1 degrees C, relative humidity of 65 +/- 10%, and an appropriate light regime (16:8 LD). Trichogramma evanescens was applied twice at a rate of 75,000 parasitoid ha(-1) at 10-day intervals at the beginning of the oviposition period of the third generation of O. nubilahs in the second crop maize. Irrigation was an important factor for the effectiveness of T. evanescens and significant differences between the 2 irrigation systems tested were observed. The efficiency of T. evanescens was higher under flood irrigation than sprinkler irrigation conditions. Egg parasitism was 81.0% and 84.3% with flood irrigation, and 66.3% and 69.2% with sprinkler irrigation in 1999 and 2000, respectively. The reduction rate of infested plants with O. nubilalis was 80.0% and 88.3% with flood irrigation, and 60.7% and 68.9% with sprinkler irrigation in 1999 and 2000, respectively. Yield increased approximately 1500-2000 kg ha(-1) under flood irrigation as compared to sprinkler irrigation.