Electrospun Essential oil encapsulated nanofibers for the management of anthracnose disease in Sapota

Abstract

Control of anthracnose disease caused by Colletotrichum gloeosporioides by use of essential oils encapsulated in nanofibres made of polyvinyl alcohol has been attempted in this study. Essential oils from plants of subtropical origin, thyme oil and betel leaf oil were incorporated in electrospun mats at different levels. The Scanning Electron Microscope analysis revealed size of the nanofibers between 180 and 302 nm. Effective Dose (ED50) values for the pure oils and their blends (1:3; 1:1; 3:1) ranged from 77 to 148 ppm. The blended essential oils demonstrated additive effect for inhibition of the pathogen with Abbott index >0.5. Oil loading capacity, determined using Gas Chromatography Electron Capture Detector ranged from 40.15–75.88% and was found proportional to feed content. No major effect of incorporation of thyme oil and betel oil on polymeric structure was observed in Fourier-transform infrared spectra. A Band near 876cm−1 and 1250 cm−1 signified the presence of both thyme and betel oil respectively. The composite nanofibers with blended oils at three levels showed inhibition zone from 6.6 mm to 11.6 mm on 3rdday of incubation, which increased further upto 24 mm on the 6th day. Sapota fruits inoculated with Colletotrichum gloeosporioidesrecorded disease severity of 83.33 %, 8.39 % and 6.72 % when packed in corrugated fiber board boxes with composite nanofibers as compared to control fruits (100 %) on the 6th day of incubation at 28 °C. Burning symptoms on skin were observed on fruits kept in contact with same level of essential oil infused sterile cotton balls highlighting the importance of encapsulated oils for disease control.