Acta Phytopathologica et Entomologica Hungarica 53 (2), pp. 213–220 (2018) DOI: 10.1556/038.53.2018.006 Efficiency of some Medicinal Plant Extracts and an Entomopathogenic Fungus, Metarhizium anisopliae Separately and in Combination with Proteus® Against the Large Cabbage Butterfly, Pieris brassicae L. F. KHORRAMI*, A. SOLEYMANZADE, Y. GHOSTA and F. POUSHAND Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran (Received: 15 February 2018; accepted: 5 April 2018) 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 hor- tensis, Trachyspermum ammi, Ziziphora tenuior, Cuminum cyminum, and Foeniculum vulgare methanolic ex- tracts 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 LC 50 value equivalent to 43.49 ppm. Proteus® also exhibited a high efficacy (LC 50 =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. Keywords: Botanical insecticide, Metarhizium anisopliae, Pieris brassicae, Proteus®, synergistic effect. Cabbage (Brassica oleracea L.) is a prominent vegetable that is consumed either processed or raw (Rokayya et al., 2013). Brassica crops are attacked by many species of insect pests that cause significant damage to them (Neupane, 1999). One of the most important pests of cabbage is the large cabbage butterfly, Pieris brassicae L., which has been recorded as a considerable and cosmopolitan pest of cabbage, cauliflower, and broc- coli (Hasan and Ansari, 2010). In addition to a direct damage, the large larvae pollute the host plant with their feces (Pfiffner et al., 2009). Today, applying chemical insecticides are still considered as the most important strategy to manage insect pests. Proteus® is a contact and systemic insecticide with two active ingredients (thiacloprid and deltame- thrin) with different modes of action. On the other hand, considering the disadvantages of synthetic pesticides such as adverse effects on environment and human health (acute toxicity, cancer, neurological damage, birth defects, and reproductive and developmental harm) and beneficial organisms suppression (such as parasitoids and predators) (Salunke * Corresponding author; e-mail: fkhorrami.khorrami20@yahoo.com 0238–1249/$ 20.00 © 2018 Akadémiai Kiadó, Budapest