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Both pipfruit and summerfruit crops continue to run early. As far as we can estimate, the harvest season is running somewhere between seven and ten days earlier than last year.
Examples we have at the moment are Firebrite nectarine - harvest commenced last year on 5 January. This year the last pick was on 4 January.
A Royal Gala grower comparing fruit size this year with last year says fruit size is fifteen days ahead of last year. I would estimate that about half of this difference is due to additional fruit size potential, while the other half of it is due to the effect of the early season.
The implications for the harvest are that:
- There will be significant crop ready for picking seven to ten days earlier than last year.
- Pesticide withholding periods will need to factor this in, and application of growth regulators such as ethylene inhibitor, aminoethoxyvinylglycerine (AVG) sold as Retain, will need to be adjusted to take account of the earlier harvest.
As flowering was short and this year there is generally little fruit being carried on lateral bud of one year wood, we can expect the harvest period to be compressed down to maybe as little as 2 weeks for a particular block. This means that harvesting needs to be well-organised and carefully planned. If the weather continues to be warm and sunny, the fruit is going to mature very rapidly.
As the Gala group accounts for 30% or more of production on many orchards, this means there will be a lot of fruit ready to harvest in a short period, so some consideration needs to be given to spreading the harvest.
These days, a lot of orchards grow the variety on a number of different rootstocks so this will give some spread of harvest.
Those on dwarf rootstocks sprayed with dormancy breakers, eg Hicane will be ready first, then untreated dwarf rootstocks and MM106 treated with dormancy breakers. These are followed by unsprayed MM106, M793 and young trees which carry most of their fruit on lateral bud of one year wood.
The strain of Gala tends to also influence block maturity. The blush red strains, Regal and Regala, tend to be earlier than Royal Gala, and the super red strains such as Brookfield and Galaxy may be behind Royal Gala by a day or two.
AVG shows good potential as a harvest management tool.
We now have three to four years experience with AVG as a harvest management tool for the Gala group.
Applied three to four weeks prior to anticipated normal harvest date, it is possible to delay harvest by about seven to tend days and with this delay secure a lift in fruit size as well.
This year, we estimate the optimum AVG application period for optimum harvest delay response to be somewhere between the 15th and 20th January for Hawke's Bay. Districts which normally harvest later will have correspondingly later applications.
Last year some trial work was done with AVG applications close to harvest. These showed no harvest delay effect, but markedly improved the quality of later picked fruit, enabling a much higher percentage of the later pink fruit to make the export quality.
Experience shows AVG to suppress colour development, so its use is not recommended for blocks with poor colour history. On the other hand, it is a very useful tool to reduce excess colour development on super red blocks which have a tendency to become too dark.
Spray concentration and spray coverage are both critical to a satisfactory result. The recommended rate is 830 g/ha of the commercial product, plus organo-silicone surfactants applied in 800 to 1,200 l of water per hectare.
The manufacturer recommends morning application under slow drying conditions. Silicone wetters are super efficient wetting agents and if water rates are too high for the target, or dew present at time of application, there is a high risk that much of the product would be lost through excess run-off. To prevent this, the trees must be dry at time of spraying.
Our experience suggests that applying concentrations around about 830 g of commercial product per 1,000 l applied with TX nozzles on a rig set up to about 600 l/ha under normal spraying conditions slowed up to apply about 1,000 l/ha will give a very good job.
AVG is a useful tool for use on other varieties as well as the Gala group. Southern Snap is the most responsive variety we have come across. It also has powerful stop-drop properties, which can be useful for blocks which are susceptible to pre-harvest fruit drop. Braeburn and Fuji often suffer from this problem.
Although Braeburn is not as responsive as the Gala group in regard to harvest delay, application about three weeks prior to harvest will hold back starch advancement and give some harvest management benefit.
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