Purdue Wine Grape Team Newsletter

Dear Indiana Winemakers,


I had the pleasure of attending the American Society for Enology and Viticulture Eastern Section annual meeting recently. About 100 academic and industry colleagues attended the conference in Dunkirk, NY, in the heart of the Lake Erie region. The presentations were excellent and I want to share a few important updates on viticulture from the meeting. You can see all the abstracts, including those in enology at www.asev-es.org.


Sour rot management: Many growers experience the dreaded sour rot each year at harvest. Discoloration of the berries, a strong smell of vinegar, and presence of fruit flies characterize this fruit rot. Sour rot is caused by miscellaneous yeasts and bacteria. Research by Megan Hall, graduate student working with Dr. Wayne Wilcox at Cornell shows that fruit flies are integral to the development of this rot. Controlling the fruit flies reduces the rot problems significantly. In field trials with Vignoles, integrating antimicrobials with insecticides provided 50% control of the disease, with negligible control by either component alone. Since we now have spotted wing Drosophila to contend with in Indiana, this is just an added benefit of late season insecticide sprays. 


Early leaf removal reduces cluster compactness and rot problems: Two speakers, Cain Hickey of Virginia Tech and Bryan Hed of Penn State, discussed early bloom leaf removal as a management practice to help reduce fruit set, and thus cluster compactness. While most leaf removal is done 1-3 weeks after fruit set, removing leaves earlier, just prior to bloom, will cause a reduction in carbohydrates available to the clusters, and reduces fruit set. While this can reduce yield slightly, the advantages of loose clusters far outweigh any minor yield reduction. Every grower knows that tight clusters rot much more readily than loose clusters. Keep your clusters loose with early leaf removal.


Managing vine vigor in the Midwest is a constant battle, especially in wet years. Dr. Justine Vanden Heuvel of Cornell is looking at the use of under vine cover crops to help manage vigor, improve soil quality, and reduce nitrogen leaching. She showed improvement with cover crops of native vegetation and white clover compared to herbicide treated and cultivated treatments. Several growers in Indiana practice this method of vigor management, even if not intentionally.


In a similar project, Dr. Tony Wolf of Virginia Tech discussed the use of root restricting bags for reducing excess vine vigor. Now in the 5th year of their project, the results are impressive. He showed a significant improvement in vine balance and fruit quality in root-restricted vines. Probably not something we'll consider in Indiana, but interesting nonetheless.


Finally, Dr. Wayne Wilcox, grape pathologists at Cornell was this year's recipient of the Outstanding Achievement Award. Wayne gave a great talk summarizing about 20 years of research on grape diseases. His work and that of others laid the foundation for how we manage grape diseases. From timing of fungicide application to cultural management techniques, this collective research has made it possible to grow grapes in the East. Congratulations to Wayne.


There are the kinds of topics we are looking at for the 2016 Indiana Horticultural Congress. If you have ideas on topics you would like to see presented, please let us know. 



Bruce Bordelon

Professor of Viticulture


Jeanette Merritt
Christian Butzke

Jill Blume

Bruce Bordelon