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w i n e G R O WIN G IBMP in wine (ng/L) from the shaded treatment in resulting wines were found. IBMP degradation patterns can differ between vintages and can sometimes overcome the effect of bunch sun exposure, in combination with the average temperature of the vintage and number, time of occurrence and length of heat waves experienced in the 20 18 16 14 12 10 8 6 4 2 0 Fresh fruit Mature fruit Harvest date Both sides exposed Shaded Figure 10: The concentration of IBMP (ng/L) in Merlot wines for the both sides exposed and shaded treatments, harvested at fresh and mature fruit stages. No decrease in IBMP concentration was observed during ripening from fresh to mature fruit stages, for both treatments. A noticeable difference in wine IBMP concentration was observed between the treatments: ~ 12ng/L for wine from exposed bunches and ~18 ng/L for wine from shaded bunches. South African grapegrowing region.2,10 • Removing all leaves and lateral shoots in the fruit zone on one side of the canopy is an effective tool to reduce IBMP concentration in a wine. The choice of the canopy side to remove leaves has to be chosen properly according to row orientation and site location to prevent possible sunburn in warm climatic conditions. The timing of leaf removal is crucial to reduce IBMP concentrations in grapes. Leaf removal performed before véraison (at berry pea size) results in a significant decrease of the IBMP concentrations in grapes, whereas treatments applied after véraison had little or no effect on IBMP concentration in grapes.10,14,16 • By removing only laterals from the fruit zone and retaining basal adult leaves of the primary shoot intact, sufficient light will be allowed into the fruit zone. Selective opening of the fruit zone would however, be more time consuming than removing both laterals and basal leaves simultaneously. • In a warm/hot climate, similar results can be obtained by indirectly increasing light in the fruit zone using a modified VSP trellis such as the Smart Dyson, the sprawling VSP (allowing light to penetrate the canopy and to reach bunches through the top of the canopy/diffuse light penetration) or implementing a new Lys training system.5 Early leaf removal before véraison seems to be an efficient tool to reduce the concentrations of IBMP in grape berries. As proposed by other authors, the IBMP concentration in the grape berry is not only light- but also temperaturedependent, which could, according to the site and vintage details, counteract the effect of the light intensity. Further research on this topic is needed, mainly to understand the complex relationships between fruit and wine composition, and ultimately wine sensory description. PWV Acknowledgements Funding was provided by WINETECH and THRIP (South Africa) and by the Slovenian Research Agency (Project L4-2042) and the Slovene Human Resources Development and Scholarship Fund (K.S.). The authors would like to thank Distell (Stellenbosch, South Africa) for providing the Sauvignon Blanc vineyard (Deon Joubert and family) in the Overberg area. We thank Eikendal Estate (Stellenbosch, South Africa) for providing the Merlot vineyard. pr actica l win ery & vin eya r d JANUARY 20 14 33