In vitro and in vivo Application of Eco-friendly Treatments to Control Postharvest Stem-end Rot of Naturally Infected Avocado (cv. Pollock)

Purpose: Stem-end rot (SER) is an endophytic fungal infection of avocado causing significant postharvest losses, affecting its marketability. This study was conducted to identify effective concentrations of selected eco-friendly essential oils and chemicals to control SER pathogens by conducting in vitro bioassays and to develop treatments to control SER in naturally infected avocado (cv. Pollock) using less hazardous alternatives to synthetic fungicides.

Research Method: In vitro disc volatilization and poison food bioassays were conducted to identify inhibitory concentrations of some essential oils and chemicals against SER pathogens. Avocado fruits were subjected to eco-friendly fumigation and dip treatments and their pathological, physicochemical and sensory properties were assessed after 7 days of storage at 15 °C.

Findings: Disc volatilization bioassay revealed that 5 µL/plate clove oil was most effective against Lasiodiplodia theobromae, Diaporthe nelumbonis and Fusarium oxysporum. According to Poisoned food bioassay, 5% (w/v) sodium bicarbonate and 0.07% (v/v) acetic acid were highly effective against the test pathogens. SER incidence of avocado fruits has been successfully delayed for 7 days after subjecting to fumigation treatment with clove oil and dip treatments with sodium bicarbonate and acetic acid, followed by storage at 15 °C. None of the treatments adversely affected physicochemical and sensory properties of avocado.

Originality/Value: Treatments could be further improved by conducting a medium-scale in vivo trial to obtain good quality avocado with higher consumer acceptance.