The efficiency of natural enemies as key factors in success of any biological control program depends on different elements including the quality of their herbivore hosts. Similarly, it may be influenced by nutritional status of host plants in turn. This study was carried out to determine the parasitism capacity of Trichogramma principium (Sugonjaev & Sorokina) on Helicoverpa armigera (Hübner) reared on tomato plant cultivars using different amount of nitrogen fertilizer.
