Developing a fungicide resistance service for citrus packers
A 12-month project aimed to develop a fungicide resistance service and provide resistance management advice/training for citrus packers has been completed.
The project was funded through the South Australian River Murray Sustainability Program and involved conducting resistance monitoring on five major citrus packers from the Riverland and surrounds, on four occasions from October 2015.
Craig Wooldridge, E.E Muir & Sons postharvest technical consultant at Renmark, jointly participated in surveys, resistance management training and provided a local resource for packers.
The program team also included Peter Taverner, Nancy Cunningham and Nancy Leo from SARDI.
The overall survey results provided a revealing depiction of the fungicide resistance pattern during 2016. Each packer had different experiences but there were a few consistent trends.
- The ‘summer break’ did not always lead to a total loss of fungicide resistance acquired the previous season.
- The use of the combination of thiabendazole (TBZ) and imazalil (IMZ) controlled decay but did not halt single fungicide resistance developing within one season.
- Resistance to the fungicide TBZ is acquired before resistance to IMZ.
- Sampling in different areas of the packing line resulted in different levels of spores and the proportion resistant to a fungicide. The results in packing lines and cool rooms of the same packer can be very different.
The program also included a component of awareness and training for packers. Packers gained understanding as a result of participating in the fungicide resistance surveys.
- The fungicide-amend plates used in the surveys provide a visual guide of mould growth, which highlighted their risk.
- The information and training provided options for maintaining or improving their situation.
- The surveys identified potential problem areas, leading to a changes in cleaning and sanitation.
- Survey plate tests can be used to verify the treatment efficiency.
- The surveys provide an early warning system that resistance is developing and can be used to guide an alternating fungicide program.
You can download the full report of project’s findings here