Issue link: http://winesandvines.uberflip.com/i/670981
86 WINES&VINES May 2016 GRAPEGROWING WINE EAST duced Botrytis incidence (per- c e n t c l u s t e r s w i t h r o t ) a n d severity (percent area of clus- ters with rot) in five and four seasons, respectively, and was as effective as two additional Botrytis fungicide applications (at bloom and at pre-harvest), suggesting potential to reduce fungicide inputs. The results also showed that delaying leaf removal until vé- raison provided little to no ben- efit, with an average bunch rot-reduction of only 14% com- pared with no leaf removal. In harmony with our earlier stud- ies, Botrytis development in- creased with the number of berries per cluster and berries per centimeter of cluster (com- pactness). The number of berries per cluster was significantly re- duced by leaf removal at trace bloom in 2007, 2010 and 2011 (see photos on page 87), and by 10 mg/L gibberellin in 2007 and 25 mg/L in 2011. The number of berries per centimeter was sig- nificantly reduced by leaf re- m o v a l a t t r a c e b l o o m a n d gibberellin in 2007, 2008 and 2011 (see table on page 83). In general, bloom gibberellin sprays were less effective at re- ducing rots than leaf removal at trace bloom (see table on page 84). Like leaf removal at trace bloom, gibberellin sprays at bloom reduced harvest rots in almost every year, but reductions were significant only in 2008 at 5 mg/L and in 2010 at 25 mg/L, for incidence and severity, re- spectively. It should be noted that gibberellin is labeled for ap- plication to some seeded wine grape varieties during early pre- bloom stages, but the bloom ap- plication is experimental and not on the label. Unfortunately, in the trials at LERGREC, applications made ac- cording to the label recommenda- tions were not as effective as bloom applications. The label restrictions are designed to avoid the potential for negative effects on bud development that can occur on some varieties in the subsequent year after applica- tion. We experienced this in our studies with Riesling during 2010 and 2011, when bloom sprays of gibberellin at 25 mg/L resulted in excessive shot berries and re- duced cluster development and yield the following season. Con- versely, no negative effects were observed on return yield in our studies with Vignoles at similar rates (Hed et al. 2011). T h e s e a n d o t h e r s t u d i e s ( D a s s a n d R a n d h a w a 1 9 6 8 , Pearson and Riegel 1983) con- firmed that the effects of gib- b e r e l l i n a p p l i c a t i o n w e r e complex and dependent on va- riety, rate, timing and even sea- son. The low rates of gibberellin used in the Chardonnay study had inconsequential effects on yield, but there was variability i n t h e b e n e f i c i a l e f f e c t s o n Botrytis bunch rot and cluster development from season to season. Nevertheless, when av- eraged over the six seasons, bloom gibberellin applications of 10 and 25 mg/L to Chardon- nay reduced rot more and cost l e s s t h a n t w o a d d i t i o n a l Botrytis-specific fungicide ap- plications; some incentive to define the spectrum of activity of gibberellin more clearly as well as its potential usefulness on other varieties (particularly hybrids), for which there is lim- ited information. None of the treatments had significant effects on juice compo- sition, though average Brix trended higher numerically in leaf removal at trace bloom in com- parison to the check in almost every year. The one exception was leaf removal at post-fruit set, which reduced titratable acidity in 2007, 2011 and 2012 when compared to the check. Trace bloom leaf removal sig- nificantly reduced yield in 2008, but not in subsequent seasons (2009-12), and did not reduce return bloom (the number of clusters per shoot). These results may be partly an effect of leaving non-defoliated canes at the head of vines for renewal after 2007, Wine Packaging by Packaging Designed & Manufactured by a Wine Maker, for a Wine Maker 4138 Vineyard Road Stewartstown, PA 17363 Tel: 800-292-3370 Fax: 717-993-9460 Phone: 717-993-2431 Naylor Wine Cellars is a lifetime member of Wine America, Pennsylvania Wine Assoc, Ohio Wine Producers and NY Wine & Grape Foundation WPN is a premier supplier to over 2,000 wineries and wine & spirits shops. Our auto bottom carriers & shippers are the perfect sturdy solution for your retail & online sales! www.NaylorPackaging.com Features & Benefits - Extra sturdy construction for the most protection - Quick & easy to pack & set up - Folds to conform to many different bottles - Trademarked design - Bio-degradable - Quick delivery from our stock - Lies flat for easy storage - Takes up half the space of comparative packages - Tested & approved by UPS and Federal Express as a preferred method of shipping bottles - Custom imprinting and packaging is available to display your logo, enhancing your brand image