Resumen
Tomato is a commercially important vegetable throughout the whole world and its availability all the year is grossly affected by anthracnose disease, hence, the need for an effective bio-control that is affordable and user friendly. This study therefore investigated the inhibitory effect of ethanol extracts of Azadirachta indica and Tabacum nicotianaon the mycelium growth of fungi associated with anthracnose disease of tomato. Tomatoes that showed black circular lesions with concentric ring and black spores were bought from Aleshinloye market in Ibadan; samples (3×3mm) from the sterilized margin of the lesion were inoculated on potato dextrose agar and observed for mycelium growth for five days. The obtained cultures were then sub cultured to obtain pure cultures which were introduced into healthy tomato fruits to confirm koch?s postulate. The in-vitro antifungal effects of ethanol extracts of Azadirachta indica and Nicotiana tabacum on isolated fungus causing anthracnose disease of tomato was investigated using agar dilution method. Based on cultural and microscopic characteristics of conidia, Colletotrichum coccodewas identified as organism causing anthracnose disease of tomato. The antifungal effect of the two ethanol plant extracts revealed that Azadirachta indica had the highest inhibitory effect of (45.00cm) at 100mg/ml and the least effect of (38.00cm) at 50mg/ml. Nicotiana tobacum equally had its highest inhibitory effect of (58.00cm) at 100mg/ml and lowest effect of (40.57cm) at 50mg/ml. This result also showed that Nicotiana tobacum had the highest inhibitory effect on Colletotrichum coccode than Azadirachta indica. Conclusively, the use of Tobacco and Neem plant extracts has antifungal activity against Colletotrichum which is responsible for Anthracnose disease of tomato. The plant could be a veritable and cheaper substitute for conventional drugs since the plant is easily obtainable and the extract can easily be made via a simple process of maceration or infusion.