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The very good start to the growing season this year (2001) in Hawke's Bay and Gisborne has set the crop for good fruit size, and an earlier harvest.
Fruit size at 50 days out from full bloom appears to be sitting right on the trend line for a good fruit size year. Compared with recent seasons, fruit size by calendar date is running about 9 days ahead. It is probable that this advancement in fruit development is already locked in, so we can expect harvest to also be earlier. We can therefore expect substantial quantities of normal Royal Gala to be ready for harvest in Hawke's Bay by the second week in February. Blocks on dwarfing rootstocks, or those treated with dormancy breaking chemicals will be even earlier than this.
The early season has important implications in regard to pesticide application. Minimum withholding periods need to be carefully calculated, so that the risk of having to delay harvest and risk over-mature fruit while waiting for withholding periods to expire is avoided.
Summer Pruning
With the good thinning and high natural drop this year, vigour on some Royal Gala blocks is rather high. Shading from excessive water shoot growth in some of these blocks is becoming a problem and could adversely affect fruit sizing, and particularly colour development. If not already completed, plucking out of water shoots needs to be done now while it is still possible to pull them out without using secateurs. Most blocks have already had the lower tree suckers pulled, so it is mainly the upper tree branches that require attention. Because we are now getting into some hot weather, the risk of sunburn is high, so be careful to leave enough leaf to provide partial shade for sunburn control. Also make sure that good, well-positioned shoots coming off the main leader are retained. These are your future replacement branches.
Check crop loading carefully
Although fruit size is big and indicating a good fruit size year, carrying excess crop load is still a risk. Fruit sizing on overcropped trees can stall. Obvious signs of this can be seen about 90 days out from full bloom in the Royal Gala. At this stage, fruit on heavy crop trees can already be as much as 3 mm behind trees with an optimum crop load, and if the overcropping is allowed to continue, the difference can quickly rise to 5 mm or more over the next couple of weeks, then by harvest be 6 or 7 mm, which translates into a crop two or three size counts lower.
Overcropping also delays harvest, lowers sugar levels and weakens colour development, so fruit pressure will become marginal before satisfactory fruit colour occurs.
Fuji, Pacific Beauty and Pacific Rose are particularly sensitive to the adverse effects of excess crop level on fruit colour development.
Last year we saw very good dividends obtained on late season touch-up hand thinning targeting areas in the orchard where the trees were clearly struggling to handle the crop.
Weak, low-vigour trees fail to respond well to chemical thinners and it is also difficult to persuade hand thinners to take sufficient fruit off this type of tree.
Pest and Disease
Many orchards are carrying significant black spot infection this year. Once this disease is established in the orchard, there is risk of further infection if weather conditions favourable to the disease occur over the summer. Later varieties, particularly Braeburn and Fuji, often experience prolonged wet weather near harvest, and can contain substantial latent black spot infection at harvest if late season fungicide cover is neglected.
Prolonged periods of rain during summer also favour black spot infection. In orchards with established black spot infection, it is important to apply protectant fungicide sprays prior to forecast prolonged periods of wet weather.
The warm early season will also favour certain insect pests, which may have more generations than normal. At present there are reports of heavier than normal codling moth catches in the pheremone traps.
Woolly apple aphid is showing signs of getting going too.
Leaf rollers will also be plentiful if dry weather sets in, forcing those living on pasture and roadside outside of the orchards to seek greener pastures within the orchard.
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