In vitro bioassays of some plant extracts against Banana anthracnose caused by Colletotrichum musae

Abstract

Anthracnose of banana caused by Colletotrichum musae is an invasive disease, which is difficult to control in the export process. Plant extracts used to control plant diseases are gradually becoming substitutes for traditional fungicides because they are safe for the human body and environmentally friendly. The study was conducted to record the prevalence of banana anthracnose in two locations and to determine the best medium for the growth of C. musae and botanical extracts for managing the fungus under in-vitro conditions. Six media viz., Ripen banana peels media (RBPM), Unripen banana peels media (URBPM), Ripen banana flash fruit media (RBFFM), Unripen banana flash fruit media (URBFFM), Banana leaf media (BLM) and Potato dextrose agar media (PDA), four botanical extracts including Garlic (GC), Mint (MT), Eucalyptus (EC) and Neem seed (NS) at 2, 4 and 6% concentrations were tested against the fungus and the control (CL) remain untreated. Potato dextrose agar media (PDA) was used as a standard semi-synthetic growth media. The prevailing frequency of the disease was high in the investigation area. The maximum linear mycelial growth of the C. musae was recorded on PDA (85 mm) followed by URBFFM (40 mm), RBFFM (26 mm) whereas the lowest mycelial growth was recorded on BLM (20 mm) and URBPM (8 mm). In-vitro experiments showed that PDA was the best medium for the mycelial growth of C. musae. Moreover, tested botanical extracts showed high variation in reducing the colony growth of the fungus. EC was found most effective in reducing the colony growth of the fungus followed by NS, GC and MT. These results suggest that all the botanical extracts may be potentially useful for controlling anthracnose of bananas, EC extract can be effectively used for the field experiment