Efficacy of essential oils in the control of cumin root rot disease caused by Fusarium spp.

The aim of this study was to evaluate the effectiveness of some natural safe essential oils in control of cumin root rot disease to reduce the pollution of environment as a result of wide distribution of synthetic chemicals which are employed as fungicides. Pathogenicity test of eight Fusarium isolates belonging to six species (F. oxysporum, F. solani, F. moniliforme, F. dimerum, F. equiseti and F. lateritium) isolated from root-rot symptomized cumin plants has proved their ability to infect the same crop involving in emerging symptoms of root rot disease in various degrees. In vitro, essential oils extracted from cumin, basil and geranium showed the highest antagonistic effect against the candidate pathogens and produced significant inhibition zones against them. Under greenhouse conditions, the treatment of cumin seeds with 3 essential oils resulted in the reduction of mean disease rating of root rot caused by all Fusarium spp. Both Fusarium oxysorum 112 and F. moniliforme 235 which gave the highest mean disease rating, were significantly inhibited by geranium and basil oils. All growth parameters (e.g. plant height, shoot fresh weight, root fresh weight and number of branches) which were altered as a result of infection with different Fusarium spp., were recovered when the essential oils were applied. Results of field experiment during two successive seasons have confirmed the results obtained from laboratory and greenhouse treatments, indicating that the three selected oils have a promising effect in the control of root rot disease of cumin as biological alternatives to chemical pesticides either singly or as a part of integrated control to conserve and protect the natural environment from chemical pollutants. (C) 2010 Elsevier Ltd. All rights reserved.