Influence of fungal pathogens and environmental conditions on disease severity, flower fall and desiccation of harvested Geraldton waxflower 1. Studies with model packages

Abstract

Summary. Flowering sprigs of Geraldton waxflower (Chamelaucium uncinatum Schauer cv. ‘Alba’) inoculated with Botrytis cinerea, Alternaria alternata or left uninoculated (control treatment) were kept in sealed plastic containers (model packages). Three relative humidity treatments (75, 90 or 100%) by 4 temperature treatments [5, 10, 20 or 5/20° C (alternated daily)] were maintained. An additional treatment of ethylene absorbent (Purafil) sachets in the model packages was included. Disease severity, flower fall and desiccation were monitored over 22 days. Both disease severity and flower fall were reduced in treatments with no inoculum, at lower temperatures (5, 10 and 5/20°C) and under reduced relative humidities (75 and 90%). However, desiccation was a problem at 75 and 90% relative humidity and at 20 and 5/20°C. Ethylene scrubbing at 100% relative humidity did not significantly reduce disease severity or flower fall. Considered collectively, our results show that postharvest disease severity, flower fall and desiccation can be minimised by keeping waxflower at ≤10˚C and ≥90% relative humidity.