Harvest with customer requirements in mind

With harvest approaching, the emphasis in the orchard has to be on how to obtain the best market result for the crop we have managed to produce.

The Fuji on the left were chemically thinned with Benzyladenine and consequently had a lighter crop load and better fruit colour than the Fuji on the right, which were not chemically thinned so carried a heavier crop. Fruit maturity and, particularly, fruit colour have been delayed compared to in the fruit on the left.

In any year there will be a huge range of fruit quality in the crop depending on the growing conditions experienced and the amount of effort put into crop husbandry.

Premium fruit should get premium prices, with lower returns for poorer fruit quality. Generally, all the fruit may have some value if the appropriate market outlet can be found for it. But often the lower-value fruit return may not cover the direct costs of harvest, transport, packaging and marketing, in which case that fruit is best left in the orchard. Preferably this fruit should be removed before harvest to reduce the labour requirement over the busy harvest period.

Incidentally, with the rise in popularity of cider there has been an increase in demand for acid juice, creating an outlet for fruit thinnings. Collection and sale of thinnings can substantially contribute to offsetting thinning and crop grooming costs.

Understand the market opportunities

The apple market comprises numerous sectors, with supermarkets taking the bulk of the crop provided the fruit meets their quality and supply requirements.

Within the supermarket sector there will be a range of grades with various price levels relating to variety, quality and supply period.

Outside of the supermarkets there is a range of other relatively small-volume markets, including export and specialist niche markets, as well as lower-quality outlets and processing.

Growers need to understand the relationships between all these outlets, their quality requirements and likely returns.

Before harvest, the crop needs to be carefully assessed to determine to which market outlets it is best suited.

The high-price premium markets need well-coloured, blemish-free fruit. Initial purchases are generally made on appearance. Repeat purchases depend on the consumers’ eating experience. For repeat purchases the initial sample needs to be crisp and juicy and have the characteristic variety flavour. Once consumers get a taste for a variety they are often prepared to overlook small visual defects such as light hail damage provided the fruit meets their expectation in regard to eating quality.

While appearance is very important, fruit condition will always win out in the long run.

The biggest turn-off for consumers is mealy, soft, juiceless fruit – all attributes associated with harvesting over-mature fruit. At the immature end of the spectrum, starchy, flavourless fruit is also a turn-off for consumers.

Good harvest management will avoid these pitfalls. For the best results, fruit needs to be picked at optimum maturity for the market for which it is intended.

The apples on the left are on the opposite side of the tree and not directly exposed to the reflective mulch. Note the difference in colour development compared to the apples on the right, which had reflective mulch on both sides of the tree.

Understand the fruit maturity progression

Within an apple orchard, even for most varieties, there will be a range of maturity both within the tree and across the blocks.

Factors that can determine fruit maturity include:

  • Crop load.
  • Orchard slope and orientation.
  • Fruit location within the tree.
  • Tree health and stress.

Among rootstocks, more dwarfing rootstocks (particularly M26) usually ripen fruit ahead of higher-vigour stocks such as MM106 and M793. Often there can be a 7–10-day spread in maturity across these rootstocks. Check dwarf rootstock blocks first for maturity.

With some varieties crop load has a huge effect on time of harvest maturity. This is particularly relevant for varieties prone to alternate cropping. ‘On’ and ‘off’ trees in a mixed block, for instance, will differ in their fruit maturity, with the light-crop trees ready to be picked before those with a heavy crop.

Warmer north- or west-facing slopes can mature fruit before south- or east-facing slopes. In locations with marginal winter chilling, the colder-facing slopes may perform better than the warmer slopes. Spring frost can influence fruit maturity within a block. Frost-prone areas within a block may mature fruit later because of loss of earlier-flower fruit being compensated for by fruit set on later weaker flowers, often on lateral buds of one-year-old wood which normally would fail to set. Fruit on lateral buds of one-year-old wood is invariably one or two sizes smaller than spur or terminal buds and ripens later.

Within the tree there can be a range in fruit maturity – some of this caused by late flowering – and as a general rule we have found upper-tree fruit will lag behind lower-tree fruit in fruit maturity parameters but is often much higher in skin colour.

Tree health and stress alters fruit maturity and will affect its suitability for storage.

Use objective maturity tests to measure fruit maturity. Testing needs to commence three or even four weeks before the expected harvest date so that the progression of maturity can be plotted against time. Once a pattern emerges it may be possible to forecast the harvest date. Use a recognised sampling procedure for these maturity tests. The objective is to get a good picture of the maturity status of the majority of the crop. This is different to the sampling required to identify which fruit on the tree is ready for harvest. The latter should include only the fruit which you think may be ready for harvest.

As part of planning your harvest strategy it may be worth doing a separate upper-tree maturity sample to determine if the upper tree needs to be picked at all in the first selective pick. Usually a full maturity test is not necessary for this sample because the starch iodine test will do the job rapidly and on the spot.

Selective picking and market allocation

Unless bloom periods are very compressed and the tree canopy is very uniform and open, apples require maturity-based selective picking to harvest uniform lines of high-quality fruit.

Usually at least three picks are required, and sometimes more.

For many blocks and varieties the first picking pass is a light skin pick designed to take off any advanced-maturity fruit (many of which may have some sun-tinting injury) in order to make the first main pick more uniform in maturity.

As this first pick may have some mixed maturity, including fruit from lighter-crop trees likely to have poor storage behaviour. Fruit from this pick should be marketed rapidly rather than destined for long-term storage. This usually happens, because there is good demand in the markets for fruit at that stage in the season.

The next pick, the first main pick, will comprise fruit with the best long-term storage potential. This is the portion of the crop which should be set aside for the longest storage.

The third pick, or second main pick, will also comprise mainly good-quality fruit suitable for medium- or long-term storage. It too should go into storage to be sold after all of the short-term stored late-pick fruit that usually depresses prices has passed through the market.

In a well-managed orchard there should not be much of the crop remaining after these two main picking passes, and that which does remain will be of generally poorer quality and have very limited storage life.

Fruit from these last picks needs to be sold rapidly and in many instances onto lower-grade market outlets rather than as a premium-brand product.

Left: Scirose trees after picking at the beginning of the harvest window. Right: Harvested Scirose fruit from a strip pick at commencement of the variety harvest window.

Pit and blotch

This post-harvest condition is tree related for pit and blotch-prone varieties, which include Braeburn, Jazz™, Kanzi™ and Granny Smith, as well as high-vigour, lighter-cropping Fuji and numerous other varieties, should growing conditions favour these disorders. Incidence is closely aligned with particular trees that have lighter crops and high tree vigour.

A good foliar calcium program is the first line of defence for pit and blotch. Unfortunately, these programs do not completely eliminate the problem.

However, incidences in the harvested crop can be minimised by identifying trees most likely to produce pit and blotch-prone fruit and harvesting their crop separately so that this fruit does not end up in the main harvest. Cool storage of fruit from these trees in air for between four and six weeks will allow any pit or blotch symptoms to express so affected fruit can be culled from the line. This will get the majority of affected fruit out and if the crop is then sold quickly further pit and blotch expression will be minimal.

Controlled-atmosphere (CA) storage tends to suppress pit and blotch expression until after the fruit has spent some time in non-CA storage, then symptoms may occur. It is, therefore, unwise to put fruit with significant pit and blotch risk into CA storage.

The six apples on the left are upper-tree fruit; the nine on the right are lower-tree fruit. Maturity in the upper tree is lagging. None of this fruit is ready for harvest but two of the lower-tree fruit need to be skin picked to even up maturity. There would be no need for this skin pick to take upper-tree fruit.

Handling damage

Bruising and stem punctures can cause significant fruit loss between the tree and market. Every time an apple is moved there is potential for injury.

Over the years many studies have been done into handling problems. It is a myth that picker finger bruising is responsible for apple bruises. Bruises are caused by either fruit-to-fruit contact or fruit contact with something hard.

Common causes of bruising include dropping rather than placing fruit into the picking bag or bucket, emptying the bucket into the bin, rough handling of the bin and use of poor-quality bins.

On the orchard, handling damage can be minimised by good staff training, having smooth tracks and making sure bin handling machinery is carefully driven to prevent any dropping or jarring of the filled bin.

Fruit maturity at the time of harvest can have quite an influence on its susceptibility to handling injury (particularly stem punctures). As fruit maturity advances, fruit susceptibility to injury increases. The extent to which this happens is variety dependent.

Many of our varieties are partial reds for which market requirement demands a colour level at the top end of variety capability. This means that fruit colour development often lags behind internal maturity, leading to delayed harvest while waiting for better colour development.

The key to easier fruit handling and harvesting at optimum maturity for longer-term storage lies in growing a crop which will colour well and reach the necessary colour early in the ripening period.

There are a number of tools and techniques which can be implemented to maximise fruit colour development.

Thinning and crop load have a huge influence on fruit colour development. For many varieties, thinning to spaced singles is an effective way to maximise fruit colour development because it removes the problem of inter-fruit shading within the bunch. The resultant reduction in crop load will help to improve fruit colour, too.

Where yields are high enough to justify the expense, reflective mulches are very effective for improving colour. The experience in New Zealand has been that the best responses to reflective mulches comes from their use in blocks and varieties that already have good colour potential.

Varieties and blocks with poor genetics in regard to fruit colour do not respond well to colour enhancement tools. Such blocks are best replaced with better colour strains or varieties.

Another characteristic to recognise about fruit colour is that it will brighten during storage. It’s the amount of surface area colour on fruit at harvest that is important, not its brightness.


Acknowledgement

This article has been produced as part of the Future Orchards® program. Future Orchards is a strategic levy investment under the Hort Innovation Apple and Pear Fund. It is funded by Hort Innovation using the apple and pear levy and funds from the Australian Government, and is delivered by APAL and AgFirst.

About the Author:

Horticultural Consultant, Agfirst, New Zealand