Bees as biocontrol agent delivery vectors: A preliminary study for geraldton waxflower flowers

Abstract

Flower fall from cut Geraldton waxflower (Chamelaucium uncinatum) during transport and handling is principally associated with pre-harvest infection and postharvest invasion by the fungal pathogen Botrytis cinerea. As a first step towards a biological disease management program, the potential use of honey bees (Apis mellifera) as vectors of Trichoderma harzianum (Trichodex®) for biological control of Botrytis on waxflower flowers was investigated. Two modifications to basic beehive design were tested to enable and/or enhance acquisition of biocontrol agent by bees. Based on experiments with these designs, a third improved design is proposed herein. Laboratory and limited field studies were conducted to determine if bees successfully acquired biocontrol agent and delivered it to waxflower cv. 'Lollipop' flowers. Bees acquired T. harzianum upon exit from the Trichodex® inoculum dispenser at 5960 ± 1197 (n=5) colony forming units (cfu)/bee. However, despite demonstrated removal of Trichodex® from the hives by bees and transfer of T. harzianum to artificial flowers (viz. plastic trays containing honey), transfer of biocontrol agent to waxflower 'Lollipop' flowers was not achieved in the course of this study.