Winegrape berry splitting - a big problem
Trials with Stopit applications on Sauvignon Blanc, to test its effectiveness in reducing the incidence and severity of berry splitting, proved to be very successful. Williams and Kettle Ltd conducted the trials at Stirling Vineyards Meeanee property in Hawkes Bay in the 1999/2000 season. Sauvignon Blanc was specifically chosen for this work as this variety is prone to berry splitting. Other varieties can also give problems in some seasons.
Grape berry splitting can be a big problem for growers. As well as the reductions in potential yield and quality, the damaged berries are susceptible to botrytis infection. When grape berries are expanding quickly over veraison they are more prone to splitting. Calcium is a critical nutrient for the grape through this period as it is important for cell division. It is a main constituent of cell walls and membranes and gives the cell walls strength and elasticity, which can reduce the risk of splitting.
Stopit was used for the research, as many grape growers have been using the product in past seasons and commented they were getting a reduction in splitting. Also recent trials from Chile on table grapes have shown big reductions in splitting where Stopit was applied. Stopit is a formulated liquid calcium from Phosyn, international specialists in crop nutrition. It contains spreaders, stickers and absorption agents, which improve performance and crop safety.
Repeat applications of Stopit resulted in a reduction of splitting incidence from 82% down to 50% and the severity was reduced from 5% down to 1% (See graph). This season the research is continuing as it is thought that with an extra Stopit application the results can be enhanced further.
Author: Michael Waites, New Zealand
Published: January 2001