Bioactivity of volatile organic compounds associated with Euphorbia hirta L. essential oil against fungi causing fruit rot disease of pawpaw (Carica papaya L.)

Abstract

Pawpaw (Carica papaya L.) is an important perishable fruit which is highly susceptible to fruit rot disease. This research evaluated bioactivity of volatile organic compounds (VOCs) associated with Euphorbia hirta L. essential oil (EO) against fungi causing pawpaw fruit rot. The EO extraction was conducted using steam distillation and VOCs were characterized by GC–MS. Mycelial growth bioassay was evaluated using the poisoned food technique at six essential oil concentrations: 0, 400, 800, 1200 1600 and 2000 ppm. Lasiodiplodia theobromae and R. stolonifer were pathogenic on re-inoculation to healthy pawpaw fruits. GC–MS analysis identified 29 and 50 VOCs from the leaves and roots of E. hirta, respectively. The EO from both plant parts effectively inhibited conidial germination and mycelial growth of R. stolonifer and L. theobromae. Therefore, E. hirta EO could further be explored as an organic approach in the in vivo inhibition of pawpaw fruit rot disease.