By MONETTE TAYLOR | South Central Texas Edition

Dr. George McEachern indicates the length a grape vine should be pruned ... about 5 feet ... to provide the best grape crop. -- Staff photo by Taylor

March 2, 2006 - With the passing of SB 877 in the Texas Legislature and the signature of Gov. Rick Perry on May 9, 2005, Texas grape growers are looking for a brighter future for state wineries and vineyards.

Although growing grapes for wine has become more evident in the past few years, the acknowledgement that wine can be shipped to customers … straight from wineries … has encouraged new producers in this area of agriculture.  

According to the Texas Wine and Grape Growers Association in Grapevine, there are around 100 wineries located in the state, at this time, with approximately 3,700 acres of vineyards. It is reported that the Texas wine and grape industry contributes about $200 million to the state economy and provides around 1,800 jobs.

On Feb. 16, grape growers gathered in Cat Spring for the 14th Annual Gulf Coast Grape Growers Field Day, to hear the latest from Texas Cooperative Extension members, from the types of grapes that grow the best in South Central Texas to how to prune vines and harvest the grapes.

Grapes that have been better suited for Texas include the Cynthiana or Norton, Blanc du Bois, Black Spanish, Favorite and Muscadines, with various varieties of European grapes such as Chardonnay, Chenin Blanc, Riesling, Sauvignon Blanc … on the white list … and Cabernet Sauvignon, Grenache, Merlot, Pitot Noir and Syrah on the red list.

Dr. George Ray McEachern, professor and Extension horticulture specialist, presented a program concerning pruning for an “optimum shoot size.” McEachern noted that in the “Coastal Region of Texas where the growing temperatures and the light intensity are much greater, vines can be very vigorous, thus needing more space per vine.”

He encouraged growers to leave more buds per mature vine at pruning to reduce the shoot size. According to McEachern, that shoot size is between 3/8 to 1/2 inch in diameter, and the shoot length is four to five feet. In the four to five feet, there should be 15 to 22 mature leaves. Due to weather conditions, he explained that Texas grape vines are larger than those in other states.

A one-year-old shoot should be the best for grape production, and McEachern suggested pruning to the buds or nodes, and advised leaving as many buds as possible. Normally, that would be between 15 to 22 buds per shoot, he said. In Texas, he suggested that the vines should be planted 16 inches apart for optimal growth and production.

Another speaker was Dr. Jim Kamas, assistant professor and Extension horticulturalist (fruits).  He explained several, major fungal diseases that can occur in the Gulf Coast area. Kamas noted that the “big three” include Downy Mildew, Powdery Mildew and Black Rot.

Before growers can address the diseases, Kamas cited three areas of understanding that would help growers: understanding the biology, susceptibility, and fungicide characteristics of the diseases.

Powdery Mildew is a problem all over Texas, he noted, and can become a problem when temperatures are hovering around 50 degrees and only .01 inch of rain. The plants are most susceptible two weeks pre-blooming, or 30 days, post-blooming. Canopy management is very important for this disease, but there are various fungicides that can be used on the vines, including Nova, Elite and DMI.

Black Rot has been appearing more frequently, due to leaf wetness, with the same time frame as the Powdery Mildew, but is found in clusters. Most Black Rot is found when temperatures reach between 75 and 80 degrees, noted Kamas. The same fungicides can be used to help rid the vines of this problem.

Downy Mildew is more “complicated,” explained Kamas, and while dark, wet canopies can cause the disease, drought conditions can cause leaves to drop off the vines, too, causing a loss of fruit and fruit quality. He noted that Ridomil is a good fungicide for this problem.

Finally, Kamas explained that the major management tools for successful vineyard production includes sanitation, site selection, and canopy management, correct fungicides and protecting large pruned wounds. He did say there are still some unknown diseases that continue to “crop up” and a grower’s best bet would be to contact the county’s Extension agent.

(For more information, growers are encouraged to join the Texas Wine and Grape Growers Association at  www.txwine.org and Texas Department of Agriculture for rules and regulations.)