Activity of some plant oils and extracts against Collectotrichum gloeosporioides

Abstract

The antifungal effects of a range of plant extracts and oils were studied in a series of in vitro experiments against Colletotrichum gloeosporioides isolated from black pepper (Piper nigrum L.). Spore germination of the fungus was completely inhibited by cinnamon (Cinnamomum zeylanicum Blume.) oils as well as by water or ethanol extracts from galangal (Alpinia galanga L. Willd.) rhizomes and cardamom (Elettaria cardamomum Maton.) leaves. Ethanol extracts were more efficient in inhibiting spore germination than water extracts. Phytotoxicity symptoms were not observed or were minimal on pepper leaves and berries or red pepper fruits when treated with cardamom extract and galangal extract and a group of oils of cardamom, Eucalyptus, lesser galangal, lemon grass, lemon myrtle, neem, pepper black and tea-tree, but were pronounced with cinnamon oils. Cardamon oil was non toxic, but was required in higher concentrations to completely inhibit germination.