Issue link: http://read.dmtmag.com/i/51841
VINEYARD 1. Vine defects such as incom- plete graft unions, incomplete root systems and poorly healed disbudding sites correlate with physiologically immature wood and the presence/activity of fun- gal pathogens. These pathogens are air and water borne. Select a nursery with clean working surfaces and good sanitation practices, as this will tend to correlate with better product quality. Extended cold storage can result in uneven and irregular vine development, as in these off-colored spur tissues of dormant bench graft. SOURCING VINES The world over, it is traditional to blame the nursery when things go wrong in the vineyard. Certain- ly this was true at the turn of this century, when the requirement for rootstocks new to the California industry prompted rapid propaga- tion, poor product quality and cries of "Black Goo" (now recognized as Petri disease). Clearly, though, nurseries can be at fault for sell- ing misidentified scion or rootstock varieties, diseased, or physically imperfect vines. Consider the fol- lowing when ordering vines: 2. Evaluate source rootstock and scion blocks for disease symptoms and check to see that the blocks you examine or request are the ones used for your orders. In my experience, nurseries tend to exchange rootstock and scion materi- als to fill inventory shortages. Plants derived from California Department of Food and Agri- culture (CDFA) certified increase blocks are supposed to be virus-free, but a recent study demonstrated that this is not always the case. In an indepen- dent analysis of 2009 riesling samples (originally published in Wine Business Monthly), 37%, 20%, 13%, 43%, 20% and 60% of 420A, 3309C, 101-14 MG, Riparia Gloire, 1103P and 1616C CDFA certified increase blocks, respectively, were positive for leafroll or corky bark viruses when tested between 2000 and 2010. 3. Where possible, select younger increase blocks and check with the Foundation source (Founda- tion Plant Services, UC Davis, for CDFA materials) as to the recall of any materials. 4. Perhaps one of the most frus- trating practices at some nurser- ies is to fail to notify clients that their order will not be filled. This data is available to the nursery or client up to six months in advance of vine delivery. There- fore, examine plants in the nurs- ery row to estimate the quantity of high-quality vines available to fill your order. 5. CDFA standards relating to vine- quality characteristics such as root system, graft union and top growth are minimal. Experience has shown that an average of about 25% of dormant bare-root product shipped from California nurseries fails to meet minimum standards. Most nursery con- tracts provide a 48-hour post- delivery period for inspection and rejection of vines. Use this time to your advantage. 62 VINEYARD & WINERY MANAGEMENT JAN - FEB 2012 WWW.VWM-ONLINE.COM