Issue link: http://winesandvines.uberflip.com/i/816747
May 2017 WINES&VINES 39 GROUNDED GRAPEGROWING roots, as they can stay submerged for weeks with little damage (many rootstocks have ge- netics from vines that grow in riparian areas). Once the vines have leafed out, however, if they are in wet areas they may grow poorly and exhibit nutrient deficiencies. Generally all will be well once the ground dries out, and shoots will once again start to grow. The one rootstock to worry about is 5BB, which is susceptible to Phytophthora root rot. Serious damage may occur to vines planted on this rootstock, and it should not be used where saturated soils are likely to occur. If you planted cover crops, you will probably have abundant growth following a wet winter. This is positive for soil health, as exudates from the roots encourage soil microflora that helps aggregate soils, cycle nutrients and suppress soil pathogens. Similarly, the cover crop's above- ground portions are a source of carbon and nitrogen (especially legumes). Getting cover crops mowed down and incor- porated into the soil may be challenging due to the extra biomass. Extra mowing and disking passes may be required. There inevitably will be wet sections of the vineyard that can sink your equipment. Try to work around those areas as best you can. It can also be a problem for no-till vineyards, as the wheel ruts will stay there for- ever, and you may need to re-till, level and reseed those areas at some point. In vineyards managed as no-till, you will probably have to mow extra into the late spring and summer, as the extra soil moisture will keep things growing longer. Beneath the vine, weed control may also require extra attention. If you are doing it with cultivation, you may have some problems get- ting weeds under control. The early passes normally done in late November or December were not possible this season. This means that when you eventually get into the vineyard, there will be much larger weeds that require multiple passes. Those fortunate enough to have sheep grazing during the dormant period will have a much easier time, as the sheep can feed when the vineyard is too wet for equip- ment to operate, and they keep weeds fairly well grazed down, requiring less tillage. If you are using herbicides, application tim- ing will determine how well your weed control is likely to perform. Early applications are likely to lose their effectiveness due to biological and chemical degradation (yes, bacteria and fungi can use herbicides as a food source), and there might also be some leaching. A second applica- svfg@sbcglobal.net 4163 Chadbourne Road, Fairfield, CA 94534 Very competitive pricing, call today: 707- 425 - 2503 We Have Macro Bins! Authorized Macro Plastics Dealer CONSIDERATIONS 1 If your pumps did get flooded, do not operate them before having them ser- viced to remove silt and moisture. 2 If you are using herbicides, applica- tion timing will determine how well your weed control is likely to perform. A second application may be required for summer weeds. 3 The foundation of a strong powdery mildew program is early season sprays with wettable sulfur or Stylet oil when vines have 3 to 6 inches of growth. 4 Pulling leaves after fruit set is also going to help reduce mildew in developing clusters, as lower humidity and sunlight exposure lessen disease development. 5 If you are growing varieties with large berries and/or tight clusters, you might want to use fungicides as odds are cluster weights and berry sizes will be larger than usual, predisposing fruit to Botrytis infections. 6 The key to leafhopper control is to start early, before large populations become damaging. Often biological control is adequate, but you may need to spray if populations are building quickly.