Antifungal evaluation of some leaves extracts and fungicide against Fusarium oxysporum f.sp. lycopersici causal agent wilt of tomato

Abstract

Abstract. Osman AOA, Mohamed IS. 2017. Antifungal evaluation of leaf extracts and fungicide against Fusarium oxysporum f.sp. lycopersici causal agent wilt of tomato. Bioteknologi 14: 1-8. Fusarium-wilt can attack tomato plants, and it is considered a crop threatening disease of the worldwide. Research was conducted to study the anti-fungal activity of various aqueous leaf extracts, i.e., peppermint, sweet basil plants and river red gum, beside fungicide Revus Top® on the growth of the fungi Fusarium oxysporum f.sp. lycopersici, a causal agent of wilt in tomato. In addition to an untreated-control, the experiment took three levels concentration for each aqueous plant extracts, i.e., 25, 50 and 100% and fungicide and applied to tomato plants.  Their inhibitory effects were investigated in terms of retarding the fungal growth percentage. The results revealed that despite the inhibitory effect of fungicide against the fungal growth was more dominant, which range from 83.2% to 100% (no growth was recorded), all levels of concentration of aqueous leaf extracts of the three test plants significantly inhibited the growth of Fusarium test compared to the control treatment. Over the course of the experiment, aqueous extracts of river red gum exposed relatively high inhibition zone (44.1, 53.1 and 53.1%) followed by sweet basil (36.8, 51.5, and 54.4%) and peppermint aqueous extract as well (35.5, 39.6 and 39.6%), respectively. There is a common preference that the highest concentration of the plant extracts (peppermint, sweet basil, and river red gum 100%) and fungicide (100%) gave the significantly highest inhibition zones percent (41.9%, 48.5%, 39.3%, and 99.3%) respectively compared to the untreated control. The results showed that the increase of the dosage of aqueous leaf extracts would consistently increase their antifungal activity. Apparently, the test fungus differs in its response to the different concentrations; but overall, growth inhibition increased with the concentration. The study results may be considered promising and serve to encourage others to carry out a phytochemicals analysis of different parts of river red gum plant using different solvents so to determine the bioactive ingredient in each of these parts.