Pieris brassicae (Lepidoptera: Pieridae) causes great qualitative and quantitative damage to cabbage crops. The present research was conducted to assess the synergistic/antagonistic interactions of Satureja hortensis, Trachyspermum ammi, Ziziphora tenuior, Cuminum cyminum, and Foeniculum vulgare methanolic extracts with Metarhizium anisopliae and Proteus® against P. brassicae pupae under laboratory conditions. The tested methanolic extracts when combined with M. anisopliae and Proteus® possessed synergistic efficacy (except for M. anisopliae + ammi). Probit analysis of extracts revealed S. hortensis as the most effective extract with LC50 value equivalent to 43.49 ppm. Proteus® also exhibited a high efficacy (LC50=48.88). The results support the potential of cumin, fennel, savory and ziziphora methanolic extracts to improve the efficacy of M. anisopliae. Results demonstrated that all tested extracts integrated with Proteus® provide more effective control of P. brassicae than Proteus® alone.