Evaluation of plant extracts for antifungal activity against Colletotrichum gloeosporioides, the incitant of leaf blight in small cardamom and anthracnose of black pepper

Abstract

Stress imposed by biological entities is considered as the major production constraint encountered by black pepper and small cardamom in India and elsewhere. Among the fungal diseases, leaf blight and anthracnose incited by Colletotrichum gloeosporioides in cardamom and black pepper, respectively, are the most prevalent and economically important diseases. In the present study, 35 plant species were evaluated to assess antifungal property against the targeted pathogen under in vitro conditions. Phytoextracts of Solanum nigrum (5%), S. torvum (20%) and Azadirachta indica (5%) exhibited maximum inhibitory effect whereas, Leucas aspera, Costus igneus, Datura stramonium, Lantana camara, Glycosmis pentaphylla and Adhatoda vasica promoted growth of the pathogen. Microscopic observations revealed abnormal morphological and structural alterations of hyphae, including increase in size and number of vacuoles, anomalous branching and abnormal swelling at hyphal tips. Information emanated from the present study indicates that, the efficacious plant species identified as potential sources of bioactive antifungal molecules could be further exploited to devise management strategies based on bio-prospecting.