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A Technical Guide for Wine Producers
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RECENT ARTICLES | WYNBOER HOME
1 PLANNING - Visit your nursery and inspect the vines that have been grafted for you to ensure that they are true to type, vigorous and disease free. - Plan irrigation schedule of various blocks. - Plan the application of nitrogen top fertiliser carefully, especially when vineyards are very vigorous. - Make the necessary arrangements and book contractor for soil that must be prepared now or in December. If soil is too dry, sensible irrigation will help create the correct soil moisture conditions. - Plan the necessary actions with regard to soil preparation, fumigation, drainage, irrigation and trellis systems. Contact VinPro (SA) agricultural economists for information about:
On a monthly basis, compare the actual expenditure with the budgeted expenditure and make adjustments if necessary.
2 VINEYARD PROGRAMME Obtain weed control for the entire season, especially in irrigation vineyards, towards the end of the month by applying a mixture of pre- and post-emergent herbicides aimed specifically at pre- and post-burgeoning. In vigorous vineyards and vineyards where botrytis rot occurs annually, no nitrogen top fertilisation should be applied. Young blocks undergoing green shoot development may be given small, regular (every 2 - 3 weeks) N-applications. Soil water content and climatic conditions should be taken into account when irrigating so as not to induce excessive shoot growth. To schedule irrigation and prevent excess, use aids such as pan evaporation figures, tensio and neutron moisture meters or even soil samples obtained with an auger or profile pit. - Oidium should still be controlled preventatively seeing that the weather conditions in the second half of the month are usually very favourable for the development of this disease (See October guidelines). - Downy mildew may pose less of a threat in certain areas due to the weather being drier and the wind more prominent, but if weather conditions are wet, stick closely to the control programme. - Chemical control of grey rot is only possible if foliage management is effective and N-fertilisation and irrigation in particular are applied discerningly. - Summer treatments to control mealybug should consist of spot spraying of individually marked vines by hand. Note the withholding period and follow IPW guidelines. - Snout beetles should only be controlled if the damage has dire financial implications. Ensure that the whole vine as well as the soil in the immediate vicinity of the trunk is properly doused. - The treatment of thrips should be applied during flowering and repeated after three weeks, if required. - The various canopy control actions improve aeration, drying and sunlight penetration as well as effective spraying of individual vines. - Suckering is the most important practice to obtain optimal foliage density. During the first suckering, which is done early, all shoots that are not on bearers, must be removed. With the second suckering action, regrowth, infertile and weak shoots with bunches are removed. In overly vigorous vines, the lateral shoots in the bunch zone may also be removed. - Tucking in of shoots between trellis strands should be done in good time to prevent the shoots from bundling at a later stage. Distribute shoots evenly between strands. - Tip / top shoots sensibly, especially in cultivars that are susceptible to botrytis. Tipping is more beneficial than topping, seeing that early topping causes lateral development in the bunch zone, resulting in compaction. The first tipping is done when shoots measure approximately 60 cm. - Breaking out of leaves ensures better aeration, light and pesticide/fungicide penetration, especially in the bunch zone. One third of the leaves in the bunch zone may be broken out, as well as excessive leaves throughout the foliage - ensure that this is done evenly - from pea berry stage or véraison. To prevent sunburn, take care not to break out too many leaves on the north and west facing sides. Where botrytis is a problem, breaking out of leaves may already begin at the berry set stage. - For environment specific advice, contact your viticultural consultant and study the VinPro (SA) Consultation Services publication "Guide for establishing a vineyard" as well as the video entitled "Groenlootontwikkeling". - The laterals on the young trunk of second foliage vines should all be removed (not the leaves), except for two laterals to be kept as future cordon arms and attached flat to the wire strand. - The cordon arms of third foliage vines must be suckered so that one shoot only is retained per bearer position. Apply crop control by leaving just one bunch per strong shoot. Tip the longest shoots so that even shoot growth is obtained. - Sucker fourth growth vines depending on vigour, leaving one or two shoots with all the bunches per bearer. - The regrowth of fifth foliage vines is suckered, as well as a third of the leaves in the bunch zone. Also thin out bunches hanging together in clumps. - Crop control, especially in young vines, is not only important for the lifespan of the vine, but may also result in poor quality grapes and harm subsequent crops (see video entitled "Oesbeheer"). A more detailed version may be ordered from Mrs Gerda Kriel at 021-8073027. Compiled by: VinPro (SA) Consultation Services |
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