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WineEast Blanc Du Bois is a hybrid bunch grape crossed in 1968 by John A. Mortensen at the Central Florida Research and Education Center. Blanc Du Bois Takes Root A winegrape found in Texas and the southeast is tolerant of Pierce's disease By Fritz Westover he southeastern United States is a difficult climate for grape production. Frequent and heavy rainfall combines with warm temperatures and high humidity during the growing season to provide ample moisture to encourage the spread of a multitude of fungal diseases in grapes. The most notable grape varieties grown in the southeast have long been the Muscadines (Muscadinia rotundifolia), because their thick berry skins and foliage resist many common fungal diseases. Most importantly, this species is resistant to Pierce's disease3 T (PD), a major bacterial grapevine disease in the southeast. Fortunately, pioneer growers and winemak- ers in the southeastern U.S. have paved the path for some alternative winegrape varieties with tremendous potential. This article will cover the white winegrape variety Blanc Du Bois, and a follow-up piece in Wine East will discuss the red variety Lenoir. Pierce's disease in the southeast The PD bacterium (Xylella fastidiosa) is a major problem in the southeast. It has been identified in susceptible grape variet- ies as far west as Texas,2 eastward into Georgia1 and as far north as Virginia.6 grape strain of this disease is found in wild The • Wine East HIGHLIGHTS: • The most common Pierce's disease- tolerant white bunch grape variety in Texas and the southeastern U.s. is Blanc Du Bois. • Texas has 150 acres in production, making 20 commercial wines from dry to dessert. • Blanc du Bois is an early variety, with bud break in March and har- vest beginning in early July. The variety is catching on because of its suitability for southern grow- ing regions and the -like flavors that make it commercially appealing. grapes that grow in the woods surrounding vineyards and is brought into the vineyard to susceptible cultivated varieties by xylem feeding insects such as sharpshooters. European grape varieties (Vitis vinifera) are highly susceptible to PD. Commercial vine- yards growing varieties such as Cabernet Sauvignon, Merlot and Chardonnay have succumbed to this disease within a few years of planting in southeastern states. The PD bacterium and its vectors favor the mild winter temperatures of the south- east and are hosted by a multitude of wild plants, making the production of V. vinifera varieties a bleak endeavor in this region. Risk maps of the southeastern region have been produced by North Carolina State University (see Pierce's Disease Risk in the Southeastern United States on page 76)1 to illustrate areas at high risk for PD such as those areas not historically receiving one to three days of winter temperatures at or below 10°F. Blanc Du Bois: a Texas triumph Blanc Du Bois (Blahnk-Du-Bwoh) is a hy- brid bunch grape that was crossed in 1968 by John A. Mortensen at the University of Florida's Central Florida Research and Edu- cation Center in Leesburg, Fla. This variety was developed by crossing European V. vin- ifera selections such as Golden Muscat with native Florida grapes and was officially re- leased by Mortensen in 1987 as a Pierce's disease-tolerant winegrape for white wine production in the humid southeast.4 The grape was named in honor of Emile DuBois, an influential grapegrower and winemaker in the Tallahassee, Fla., area. Wines & Vines FeBRUARY 2012 75 vinifer a