Efficacy of stingless bee (Heterotrigona itama) propolis aqueous extract in controlling anthracnose and maintaining postharvest quality of chilli (Capsicum annuum) during storage

Abstract

Anthracnose, mainly caused by Colletotrichum spp., is one of the fungal diseases resulting in major economic losses affecting chilli production worldwide. Propolis extract from honeybee has been discovered for its antifungal properties, which can potentially reduce postharvest decay. Therefore, the present work investigated the efficiency of aqueous extract of stingless bee (Heterotrigona itama) propolis in controlling postharvest anthracnose and maintaining quality of chilli. Colletotrichum capsici was isolated and characterised from infected chilli. Stingless bee propolis extract at different concentrations of 1, 2, 5, and 10% were assessed in vitro to inhibit the mycelial growth of C. capsici. The best concentration in inhibiting C. capsici growth was thereafter selected for in vivo experiments. All tested concentrations of stingless bee propolis extract inhibited the mycelial growth of C. capsici the highest being 35% inhibition from the treatment of 10% propolis extract. The extract at this concentration was therefore tested in vivo, and showed effectiveness in reducing the percentage of disease severity in chilli. The propolis extract was also efficient in reducing weight loss, retaining firmness, pH, total soluble solid, and colour (a* value) throughout 21-day storage at 10°C. The present work demonstrated that aqueous extract of stingless bee propolis could have the potential to control anthracnose disease and delay deterioration, thus maintaining the postharvest quality parameters of chilli. This natural product from stingless bee has the prospect to be an alternative to synthetic fungicide.