Sean Gresham, Ph.D.
Now that the end is in sight for harvest 2024, everyone deserves a rest, some care and attention – the trees included. The next month or so is the prime time to ensure next year’s crop is set up nicely before the trees go into dormancy. The primordial cells that will become fruit in 2025 are already on the tree as differentiated buds. From now until leaf fall, the trees accumulate nutrients and carbohydrates that they use next spring to push out new growth and help set fruit. A bit of post-harvest care can help to get a running-start next season.
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- Post-harvest foliar fertilisers – as the leaves senesce, they draw nutrients and carbohydrates into the tree. It has been a challenging season for many blocks recovering from flooding and a cool spring followed by warm dry summer. Leaf tests will indicate which nutrients are lacking. Nitrogen and Boron are the most important followed by a number of other macro and micro nutrients.
- Sanitation for wood-invading disease – cankers and die-back will be more obvious before leaf fall so is the prime time to aggressively remove to reduce inoculum going into leaf-fall. Fungicide applications over leaf fall and pruning also help protect wounds from infection.
- Sanitation for foliar and fruit diseases – Leaf-fall urea applications were standard practice for reducing overwintering blackspot – until it was shown this prolongs susceptibility of leaf scars to disease infection. Consider ground-based application onto the fallen leaves if blackspot carry-over is a concern. Remove any remaining fruit from trees as they can harbour a multitude of fruit diseases.
- Drainage – A flush of new root growth usually occurs in autumn but can be limited by inadequate soil oxygen if soils are excessively wet. Now is a good time to assess effectiveness of drainage under ‘normal’ autumn conditions this year.
- Irrigation – If rain doesn’t come, tree health and spring potential is limited as the tree continues to accumulate carbohydrates until dormancy. Keep an eye on the soil moisture levels and irrigate if necessary, especially if soil was maintained at controlled deficit going into harvest.
- Pruning plan – Post-harvest is a good time to set priorities for pruning while trees are in full canopy and harvest is still a fresh memory. It is also the last chance for vigour-controlling pruning.
