What was it all about?

This project aimed to optimise avocado yields, fruit quality and tree health by improving the management of diseases affecting fruits, roots and whole trees.

The work included assessment of rootstocks under high Phytophthora root rot pressure; evaluation of improved applications of phosphorous acid; evaluation of improved integrated approaches for managing post-harvest diseases; and investigation of management options for brown root rot.

The researchers found a number of measures that can be incorporated by avocado growers to improve productivity in the medium and long-term.

Their advice included:

• Take extreme care when planning and planting orchards, particularly if replanting an old avocado block. Trees are more likely to die if planted into a site soon after removal of declining trees.
• Significant increases in avocado productivity can be achieved by adoption of Phytophthora root rot tolerant rootstocks, with Dusa currently available and new rootstock SHSR-04 being evaluated by ongoing industry work
• Growers should review their spray technology and ensure that pesticides and other treatments are delivered as efficiently as possible
• Greater productivity from healthier trees can be achieved by more efficient use of phosphonate as a low-volume spray application
• Industry standard fungicide sprays still provide the best quality fruit. Industry standard copper + late season strobilurin sprays most consistently reduced damage from anthracnose, but stem end rot remains more difficult to control.

Full recommendations from the research have been made available to growers through field days, via the media and in printed materials.