Fungicidal activities of certain methanolic plant extracts against tomato phytopathogenic fungi

Abstract

The fungicidal activity of five methanolic plant extracts from Lantana camara, Salvadora persica, Thymus vulgaris, Zingiber officinale and Ziziphus spina-christi were evaluated for their antifungal efficiency on tomato phytopathogenic fungi, Fusarium oxysporum, Pythium aphanidermatum and Rhizoctonia solani, the causative agents of tomato damping-off diseases. Three of five plant extracts were effective against thees phytopathogenic fungi. T. vulgaris and Z. officinale extracts were strongly active and showed fungistatic and fungicidal activities against the phytopathogenic fungi with minimal inhibitory concentration (MIC of 4 mg ml-1 and minimal fungicidal concentrations (MFC) of 8 mg ml-1 except F. oxysporum which was less sensitive and its MFC reached to 16 mg ml-1 of Z. officinale extract. On the other hand, S. persica extract showed a moderate antifungal activity while L. camara and Z. spina-christi were not effective against tomato phytopathogenic fungi except P. aphanidermatum which was completely inhibited at 10 mg ml-1 of L. camara extract. Carbendazim fungicide was more effective than all methanolic plant extracts inhibiting mycelial growth of all phytopathogenic fungi at 8 ppm and a huge concentration reached to 8 mg ml-1 of the effective plant extract was required to attain the same effect. Analysis of the effective plant extracts by GC/MS revealed that T. vulgaris extract was mainly composed by thymol (38.73%), carvacrol (19.31%), β-cimene (10.13%) and α-terpinolene (5.94%) while Z. officinale was mainly composed by Gingerol (46.85%), cedrene (8.39%), zingiberene (7.41%) and α-curcumene (7.32%) respectively. These effective plant extracts may contribute to development of potentially effective and environmentally safer alternative fungicide to control tomato damping- off phytopathogenic fungi. Key words: Fungicides, plant extracts, fungitoxic properties