A Guide to Grapevine Abnormalities in South Africa - P.G. GOUSSARD

PART 1

In practice, where the productive and sustainable performance of any vine is associated with an expected life expectancy of at least 25 years, the quality of establishment material is very highly rated. Given the local situation regarding plant improvement, an urgent and important appeal is made to producers to at all times insist on certified nursery vines from registered nurserymen/growers. In this way one can ensure that only the best available material is planted. A further recommendation could also be to build a trustworthy relationship between producers and growers, in which case experience has shown that the latter would not be reluctant to act if problems are experienced with young plantings – especially regarding virus associated phenomena (Photo 1), as well as cases of problems with graft unions (Photo 2) and root formation (Photo 3). The same approach could apply where problems associated with delayed or absence of bud burst, yellowing of foliage, stunted shoot growth (Photo 4) and complete die-back (Photo 5) of young vines should occur. In this regard certainty must be obtained concerning among others the presence and contribution(s) of Petri’s disease (black goo) and blackfoot to the discolouration, decay and blockage of vascular tissue associated with the abovementioned situations (Photos 6, 7, 8 and 9). Besides plant material, correct and careful soil preparation, handling of grafted vines when collected from nurseries as well as correct and scrupulous planting procedures are of equal great importance so as to obtain a minimum life expectancy of 25 years and even more, but also to ensure continued sustainable and profitable returns. In this regard complete and richly illustrated guidelines regarding correct soil preparation practices, planting of vines and young vine development procedures have been set out in detail by Archer & Hunter (2010). The precise compliance with these recommendations then makes it easier to ascertain the cause(s) of specific problem situations as indicated above, should they occur.

A Guide to Grapevine Abnormalities in South Africa • 9