In Vitro and In Vivo Activity of Selected Plant Extracts against Papaya Carica papaya L.) Anthracnose (Colletotrichum gloeosporioides)

Anthracnose is the major postharvest disease of papaya wherever the fruit crop is grown. The present investigation was conducted with the objectives of evaluating plant extracts for their activity against Colletotrichum gloeosporioides in vitro and for controlling anthracnose on artificially inoculated ‘solo’ papaya fruit. Plant specimens were collected from Ambo and Haramaya, Ethiopia, dried under shade and extracted using methanol. Out of 18 plant extracts tested, nine of them showed activity against C. gloeosporioides. Methanol extract of Echinops sp. of 10 μL from the concentration of 50 mg/ml resulted in the highest inhibition zone of 13.5 mm against mycelial growth of C. gloeosporioides. Spore germination of C. gloeosporioides was reduced by 98.7%, 97.7% and 97.3% over the control by extracts of Echinops sp., Thymus serrulatus and Ocimum lamifolium, respectively. Among four botanicals evaluated in vivo as 10% and 25% aqueous extracts, Echinops sp. at 25% concentration kept disease severity score at 1.3 out of 5 (i.e. less than 1% fruit surface affected) and maintained quality of papaya fruit during 14 days experimental period. Further study is necessary on sensory analysis and developing botanicals as natural fungicides