Application of Essential Oils Extracted from Peel Wastes of Four Orange Varieties to Control Anthracnose Caused by Colletotrichum scovillei and Colletotrichum gloeosporioides on Mangoes

Abstract

A huge amount of orange peel waste is annually discharged into the environment. Processing of this waste for the control of post-harvest fruit diseases can reduce environmental pollution. Essential oils (EOs) from fruit peels of Citrus reticulata × sinensis (Sanh cultivar) and Citrus sinensis (Xoan, Mat and Navel cultivar) were investigated for their ability to control anthracnose caused by Colletotrichum gloeosporioides and Colletotrichum scovillei on mangoes. EOs were extracted by hydro-distillation and analyzed by GC-MS and GC-FID. The antifungal activity of the EOs was determined by in vitro and in vivo assays. The Mat cultivar had the highest extraction yield of 3% FW, followed by Xoan (2.9%), Sanh (2.2%), and Navel (1%). The chemical composition of the EOs was similar, with limonene as the main compound (around 96%). The antifungal activity of EOs was not different, with a minimum fungicidal concentration of 16% for both fungi. The disease inhibition of EOs increased with their concentration. The highest inhibition of anthracnose caused by both fungi on mangoes was achieved at 16% EO. EOs had no adverse effect on mango quality (pH, total soluble solids, total acidity, color and brightness of mangoes), except firmness and weight loss at high concentrations (16%). Orange EOs can be used as bio-fungicides to control mango anthracnose at high concentrations.