Abstract
This study aimed to test the biocontrol efficacy of cumin (Cuminum cyminum L.), basil (Ocimum basilicum L.) and geranium (Pelargonium graveolens L.) essential oils, as a safe alternative for wilt and root rot of sweet basil (O. basilicum) caused by Fusarium oxysporum, F. solani and F. monihforme. Results showed that F. oxysporum AUN 520 and F. oxysporum AUN 524 caused 41% and 35% of basil wilt, respectively. However, F. solani AUN 537 and F. monihforme AUN 670 did not cussed any wilt symptoms but caused high degree of root and crown rot of the plants. Results, obtained from the in vitro test, approved the efficiency of the three oils in suppression of the growth of the tested fungi. Basil essential oil caused the highest inhibition of the four fungi. The three oils succeeded to protect the basil plants against the phytopathogenic fungi either in pots or under field conditions. In vivo, basil essential oil reduced the wilt percentage to 4.3% and 4.6% compared to 31.2% and 40.3% that were caused by F. oxysporum AUN 524 and F. oxysporum AUN 520, respectively. In addition, this oil involved in reduction of the root and crown rot of the basil plants to 88 to 94% of the infected plants. Under greenhouse conditions, application of basil oil increased the productivity of the treated plants significantly compared to the untreated control. The tested oils showed a promising efficacy in the control of basil root diseases, as well as stimulation of the overall growth and the productivity. For the first time, the results on field scale recommend the application of the essential oils as good alternatives to the chemical fungicides in the control of root diseases of the basil plants. (C) 2018 Friends Science Publishers