In this research, the effect of essential oils of Fennel (Foeniculum vulgare), peppermint (Mentha piperita) and Lavender (Lavandula angustifolia) and Trichoderma harzianum antagonist fungus isolates on Penicillium digitatum, causal agent of citrus green mold in in vitro and in vivo (on fruit) Was reviewed. In doula culture test, between essential oil and pathogen, the Fennel essential oil had the most effect (49.42% inhibition) and peppermint essential oil had the least effect (8.39% inhibitory) on preventing the growth of Penicillium mycelium. The essential oils of fennel and lavender with a 1500 μL / L concentration were used for in vivo tests. The 6 Trichoderma isolates were used in doula culture test. The isolate 2 had the highest effect (51.2% inhibition) and isolate 6 had the least effect (33.14% inhibitory) on inhibiting the growth of the disease agent. The isolates 2, 3 and 5 which had the highest inhibitory in laboratory were selected for in vivo tests. Orange fruits were inoculated with suspension pathogen at a concentration of 105 × 1 spore in 1 ml sterile distilled water and then treated with essential oil. Fennel essential oil was more effective than lavender in controlling Penicillium fungus on fruit. The antagonistic isolates effects on citrus green mold at 4 and 20 ° C was studied using two methods of immersion and spraying of fruits with suspension of antagonists. The highest prevention percentage of disease, against the infected control was observed of Trichoderma harzianum isolate 2 with 57.6% inhibitory and the least was isolate 5 with 13.41% inhibitory All essential oil and antagonist treatments compared to infected control, had significant difference in both in vitro and in vivo conditions, but among the all essential oils and antagonists, isolate 2 had the highest percentage of disease control in both conditions.
