Physical Factors
Climate
Waikato blueberry growers again experienced a severe frost event on 26 September 2002, with temperatures between 0oC and -5oC for seven hours. This was followed by a further week of ground frosts in early October, although not as severe. For the third year in succession frost caused extensive damage in blueberry production areas, on varieties which were just starting to bloom.
The same frost events, particularly on 26 September and 5 October 2002, caused extensive damage to early season strawberry flowers in Auckland and Waikato.
For raspberry, boysenberry and blackcurrant growers, winter chilling was only moderate, followed by cool conditions in late September and early October.
Fine, warm weather from mid-flowering resulted in good fruit set for blackcurrant, boysenberry and raspberry crops.
Production
Blueberry yields improved this season (refer Table 1), with the extent of frost damage not as great as in the previous season. Total crop volume is estimated to be up by 6% this year on the 2001/02 season.
The level of anticipated production increase for the blueberry industry has not been realised over the past three years due to the effects of frost damage. There is concern about the capacity of the industry to handle, and profitably place, all fresh export blueberries when a growing season without frost damage occurs. Another impact of spring frosts was that the harvest was late and there was relatively little fresh product available for export in November. This has traditionally been a high value market window for New Zealand fresh blueberry exports.
The consequence of early spring frost for strawberry growers was that the volume of crop harvested and supplied in October was very light. Due to warm and favourable weather conditions through the latter part of October and into November 2002, strawberry flowering continued into the season and yield harvested in November and December was very high. Total harvested yield was better on average than for 2001/02 by about 8-10%.
The absence of heavy rains during the harvest season ensured greater, marketable strawberry yields. There was less fruit lost due to fruit or plant root rots.
Strawberry plant sales indicate a 15% contraction in planted area anticipated for 2003/04. Plant sales were around 19 million in 2002, compared with the 16 million plants that are anticipated to be sold this year. The reduction reflects a number of smaller growers leaving the industry. Some larger growers are actually expanding planted area for 2003/04.
For raspberry, boysenberry and blackcurrant growers, the main effect of moderate winter chilling was that flowering was prolonged, resulting in a longer harvest. Fine weather prevailed at harvest allowing for good recovery rates of harvestable yield. The longer harvest period meant that more passes were required by mechanical harvesters to pick the crop. This means that canes may have been subjected to increased damage during more frequent harvest machine passes. The effect on plant health will not be evident until the next growing season.
Boysenberry yield recovered to the industry average of 15.0 t/ha this season. There continues to be expansion in planted areas by established growers who have already made the investment in high cost capital items for harvest and post-harvest activities.
Many young blackcurrant plantings in the first or second season of production achieved yields greater than 10 t/ha in 2002/03. The favourable weather conditions at flowering and harvest resulted in higher than predicted average yields and total production in 2002/03.
Table 1: Long-term Average and Seasonal Berryfruit Yields (t/ha)
Crop |
Long-term |
2000/01 |
2001/02 |
2002/03 |
Blueberries |
6.0 |
5.4 |
5.4 |
5.8 |
Strawberries |
23.0 |
25.0 |
24.0 |
26.0 |
Raspberries |
6.0 |
4.8 |
4.8 |
6.0 |
Boysenberries |
15.0 |
9.6 |
8.25 |
15.0 |
Blackcurrants |
5.0 |
4.5 |
3.6 |
6.4 |
Sources: NZ Berryfruit Growers' Federation Inc, Strawberry Growers New Zealand, Blackcurrants New Zealand Ltd and NZ Boysenberry Council
Contact for Enquiries
Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0623
Fax: +64 4 894 0741
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