Determination of efficacy of some essential oils and plant extracts against Fusarium oxysporum f. sp. radicis-cucumerinum, causal agent of crown and root rot of cucumber

Root and crown rot caused by Fusarium oxysporum f. sp. radicis-cucumerinum is one of the most important diseases limiting cucumber production in greenhouses and fields in Turkey and around the world. In this study, the efficacy of anise (Pimpinella anisum), juniper (Juniperus communis), pine (Pinus pinea), eucalyptus (Eucalylptus obliqua) and neem (Azadirachta indica) essential oils, and calendula (Calendula officinalis), milk thistle (Slybum marianum), dandelion (Taraxacum officinale), reishi mushroom (Ganoderma lucidum), field horsetail (Equisetum arvense) extracts on the inhibition of the mycelium growth and disease development by Forc were determined at 50, 100, 200 and 300 ml/100 l water/acre doses in in vitro and vivo conditions. Essential oils of anise and pine were determined to be the most efficient oils against the fungus in in vitro. Anise oil inhibited mycelial growth of Forc over 95 % at the doses of 100, 200, 300 ml while pine oil inhibited at the same rate at 200 and 300 ml doses. Eucalyptus and juniper oils reduced the mycelium growth of the fungus at the rate of %55-83 at the same doses. The plant extracts of calendula and field horsetail prevented Forc mycelium develepment at the rates of %30-42 at 200 and 300 ml doses. In In vivo studies, anise and pine oils prevented the disease develeopment by Forc almost %100 at 200 and 300 ml doses. The oils of eucalyptus and juniper were effective less than %35 at the same doses. The calendula extract did not prevented the root and crown rot of Forc in in vivo assays. The results of this study indicate that the essential oils of anise and pine could be used to control Forc starting at the seedling stage in cucumber production. The proper formulations of these essential oils must be developed and tested in greenhouse and field conditions to determine their potentials as biological fungicides.