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March 2018 WINES&VINES 61 the crew may have to follow up later with a second pass. Labor efficiency is likewise re- duced if shoot removal is performed after the base of shoots have begun to lignify, which makes removal slower. Therefore, finding the "sweet spot" in growth stage for implementa- tion of each vineyard-management practice, as well as the ability to predict that window of opportunity, is critical. Vineyard pest and disease control programs are implemented with great consideration to grapevine phenology. Growers who have read articles or attended talks by grape pathologists such as Dr. Wayne Wilcox of Cornell University will recall that the greatest window of disease susceptibility is from the period beginning two weeks before bloom and extending four weeks past fruit set. This is the time when growers should be using their best products and can- opy-management practices for preventing fun- gal diseases on the fruit and the canopy. Additionally, a fungicide with a long pre-har- vest interval (PHI), such as mancozeb (with a PHI of 66 days), must be taken out of a spray program based not on calendar date, but on a phenological indicator. In 2017, for example, growers in Texas stopped using mancozeb products a full two weeks earlier than average due to record-early bud burst dates. The life cycles of grapevine insect pests also are tied closely to grapevine phenology. A grape berry moth, for example, must have a young flower or berry cluster to lay eggs in to ensure a food source for its larvae. If egg laying occurs too far before bloom, survival of the next generation will be impacted. Research by Teixeira, Mason and Isaacs at Michigan State University showed that the majority of adult males entered commercial vineyards from ap- proximately 150 to 750 growing degree-days (GDD), with the GDD accumulation beginning March 1 (base temperature 47° F). Additional work by Mason and others found that it was preferable to use the bloom date of a common wild grape species (Vitis riparia) as the begin- ning of GDD accumulation for grape berry moth emergence and egg laying instead of using a calendar start date. The use of a phenology-based start date for GDD accumulation based on an indicator spe- cies common to a region is referred to as a 251 Gambee Road, Geneva, NY 14456 Phone: 315-759-2118 Toll free: 888-234-6752 Fax: 315-789-1848 Email: tanks@vancemetal.com Website: www.vancemetal.com Quality Rugged 12 gauge, Custom & Stock Stainless Tanks Catwalk Systems • Pump Over Carts • Custom Hoppers, Chutes & Bins WINE EAST GRAPEGROWING Young vines tend to have shallower root systems that are more sensitive to fluctuating conditions in the soil surface, including temperature and moisture.