Cox’s Orange Pippin and clones for medium (December/January) to long-term storage (February/March)
Picking dates of Cox for storage should be guided mainly by firmness of the fruit at the point of harvest. To achieve 6 kg firmness in fruit stored in CA (1.2% O2 <1% CO2) at 3.5oC until January or March, the minimum firmness at harvest should be 8.2 and 8.7 kg respectively.
Growers should not rely entirely on fruit firmness especially in years when the change in firmness is too gradual to provide a clear indication of when to pick. In this situation the change in starch pattern should also be used. Cox for long-term storage should be picked when the percentage of the cut surface stained blue/black is between 80-90% and no lower than 70%.
When starch levels remain high then firmness can be used to decide when to harvest. However, where firmness remains high but starch declines to 90-80% then picking should commence and be completed by the time that starch declines to 70%.
Growers should start testing for starch and firmness about 2-3 weeks before the expected/predicted date for the commencement of harvest for long-term storage. Experience has shown that mid-August is an appropriate time to begin monitoring Cox maturity in order that a reliable ‘trend’ can be established.
‘Trend’ lines are normally too variable to accurately predict when fruit will achieve critical levels of starch or firmness. However, approximate predictions can be made using an average figure for starch loss of 2% per day and firmness loss of 0.1 kg per day (‘Effigi’ penetrometer fitted with an 11 mm probe).
Greatest benefits from SmartFreshTM application are achieved on fruit picked at the correct stage of maturity for storage. However, starch coverage should be less than 70% in order to reduce susceptibility to stem end russet browning.
Cox’s Orange Pippin and clones for immediate sale or short-term (October/November) storage.
Cox apples with an average starch iodine staining pattern of less than 70% (black) have a higher potential eating quality but are only suitable for short to medium term CA storage (Table below). They should remain in an acceptable condition for up to 3 months in CA (1.2% O2 <1% CO2) storage at 3.5oC.
In many cases particular producer or marketing groups have developed their own maturity ‘standards’ in order to supply their retail customers with fruit of a higher sensory quality for a limited period.
Harvest maturity parameters issued by the Quality Fruit Group for Cox apples intended for immediate sale and for CA storage for different periods. (N.B. Air storage of Cox apples should be terminated by mid-October unless SmartFreshTM is applied after harvest
| Marketing periods | Minimum values at harvest | |
|---|---|---|
| Firmness (kg) (Penetrometer fitted with an 11 mm probe) |
Starch (% cut surface stained black) |
|
| Feb/March | 8.6 | 75 |
| Jan/Feb | 8.2 | 70 |
| December | 8.0 | 60 |
| Mid November | 7.7 | 60 |
| Mid October | 7.5 | 50 |
| Immediate | 6.5 | <50 |