NATURAL EXTRACTS OF MUSHROOM AND GARLIC AS BACTERICIDE ALTERNATIVES AGAINST POTATO SOFT-ROT BACTERIA, Erwinia carotovora subsp. carotovora

Current study aimed to search for safe and effective natural products to control the potato soft-rot disease, Erwinia carotovora subsp. carotovora. Antibacterial efficiency of edible mushroom extracts (MEs) and garlic essential oil (EO) were compared with two bactericides; streptrol and oxolinic acid as well as two fungicides; mancopper and copper oxychloride. Bioassay experiments were conducted using the paper disc diffusion and potato slices methods. Results showed that both natural extracts and synthetic pesticides exhibited marked in vitro antibacterial activity particularly streptrol and the chloroform extract of the mushroom which showed 3.4-fold inhibitory effect compared with garlic EO. Also, the chloroform extract of mushroom showed similar activity to mancopper and copper oxychloride. Mixing garlic oil (1 mg/ml) with streptrol or oxolinic acid (at 0.05 mg/ml) synergized the inhibitory effect of both synthetic bactericides. The overall results suggest the potential use of the edible mushroom extracts and garlic essential oil for the control of soft-rot disease on potatoes. INTRODUCTION Potato (Solanum tuberosum L.) is the most important vegetable crop in Egypt for both local consumption and exportation. Potato