BLACK GOO DISCLAIMER: Like much on the www. this is free and you know what you get for free! Anyway, this is a history of our attempts to solve problems in the vineyard. They do not reflect "official" views.
A) A short history of vine decline
Malvasia Bianca was originally planed in 1989 and the first 100 vines grew like weeds, have continued to do so and yield an average of 25 lbs of fruit per vine. In 1995, 500 more vines were planted, given extra trellis space to spread and to our surprise and disappointment, failed to show sustained growth. These vines are less than 200 ft. from the original plantings! Frustrated by the waste of effort/money/time, last year we initiated an approach, which hopefully will solve the problem. It involves the retraining from fixed cordon/Smart-Dyson/ballerina trellis to a vertical shoot positioning system (VSP) where the fruiting cane is always replaced. The first photo shows a vine exhibiting poor renewal growth typical of 90% of the vines. In the Spring of 1999, several of the vines were decapitated, and during the subsequent growing season, showed explosive renewal from the head, indicating that although the side arms of the vines were atherosclerotic, the main trunk was fine. This vine was then pruned down to two canes, two buds retained for renewal canes and the vine tied down to a lower single wire and additional 3 pairs of vertical catch wires installed We will update these photos during the growing season and show the additional feature of this retraining procedure. As the rows were over 10 ft wide, the use of VSP meant we had wasted at least 3 ft of row width. As we have also reached the end of usable vineyard space and had 400 Corvina Veronese vines arriving, we decided to take a lead from a Dry Creek area vineyard and plant new vines 2.5 ft away from the Malvasia vines and stagger the placement of the plants. We are currently preparing the ground for planting and will update this event in future listings. As of 04/25/00 the vines are in the ground and if it ever gets warm they may grow!
B) BLACK GOO
The demise of these vines was broadly ascribed to the general term of "black goo" disease. This has recently attracted attention in California as a cause of young vine decline. While the etiology of the disease is not clear, it is apparent that gradual death occurs unless steps are taken. Perhaps even if! We have attempted to have the best of both worlds by replanting a new variety close by ( see above Corvina plantings) and at the same time, attempting to renew the ailing Malvasia vines. The following photos demonstrate the general appearance of the diseased vines and the progress we are making in renewing the vigor by going to a training system in which old wood is removed each year so that the problems associated with "atherosclerosis" can be avoided. In essence, we are replacing year old wood with new wood. We will keep a log on this vine during the 2000 season as well as the 2001 season to see if the Malvasia vines can be rescued.
C)As of May 12/00 it certainly appears as if the vines will prosper!
The response to amputation has been amazing. The section below shows the cut site and the dry "black goo" as it appeared May 12th. The succulent growth has appeared out of every possible node! All this from a vine that could barely put out 6 inches of growth from spurs the previous year. The excess shoots will be removed and the four best retained for VSP management next year (two for fruiting canes and two for renewal buds). The two largest canes are already over 3 feet long! The vine was amputated in March. The expectations are that this vine (and the other 200 that were similarly treated this year and show similar growth response) will continue to grow well under VSP. The big question is if these aggressive canes not only will be fruitful but will in fact pump nutrients next year! It is possible that we will have to "amputate" part of the fruiting cane next year in the Spring to encourage growth. D) I submitted these pages without posting what had happened to last years experimental vines that were treated in a similar manner. Below is a photo taken May 24th of a typical vine renewed as described, that showed strong cane replacement in 1999, and now is showing strong flowering and shoot growth that appears to be exactly what the doctor ordered. This is one arm only of the vine. Here, for the doubters, is a current picture on the right from the 2002 harvest, showing abundant fruit and renewal. The vine on the left was amputated in 1999. It does have two trunks, and one trunk cam be amputated again as required.