What was it all about?

A number of agrichemicals including insecticides, fungicides, growth regulators and herbicides are used to produce citrus fruit of excellent quality. While use of integrated pest management is widespread in Australia, it is anticipated that in the near future, lower residues on produce will be necessary to fulfil market requirements.

This project began investigations into lower residue production, known as the zero residue concept for citrus.

The work began with a review of current chemical use in Australia and how this compares with overseas citrus production. A search was made for information on chemical residues, chemical degradation rates and any emerging technologies that allow reduced chemical use.

Since a number strategies would be needed to reduce chemical residue across different cultivars, growing regions and chemical use groups, a technical expert group was established to develop strategies from grower to point of sale.

The final stage was identifying gaps in the proposed strategies and in relevant research and development.

Key findings included…

• Zero residues could be attained by the Australian citrus industry but achieving the lowest residue (ultra-low residue) is a far more realistic and practical goal
  
  
• Not enough is known about the rates at which particular agrichemicals degrade
  
  
• Successful ultra-low residue citrus production will rely on the development of a suite of tools and strategies, including residue prediction tools, low residue pest and disease management strategies and regional demonstration orchards
  
  
• The best strategy would be for researchers to build alliances with companies and groups that have a good chance of meeting ultra-low residue targets
  
  
• Reducing postharvest chemical residues should be an integral part of any ultra-low residue program.

The researchers recommended increasing participation in the National Residue Survey citrus program, and collating data from grower spray diaries to provide the necessary data on chemical use and degradation of residue over time.