Phomopsis control in the Limestone Coast

Abstract

This trial showed that spraying on a calender date of regular intervals is unsuited for the control of Phomopsis and suggested that control is likely to be most effective if protectant sprays are applied before and as close as possible to a rain event.

Summary

To demonstrate the importance of spray timing and to provide a site suitable for a vineyard walk to demonstrate symptoms, trials were initially set up in 2008 in vineyards known to be infected with Phomopsis. After two fungicide applications in spring the trials were abandoned as the weather was dry and unsuitable for the disease development. One trial was repeated in 2009 where different spray timings of the fungicide Polyram were applied either I,2,3 or 4 times at approximately 14 day intervals from green tip bud burst. Assessments in late November showed that the amount of disease was similar in all treatments including the unsprayed. The trial demonstrated how effectively Phomopsis carries over for several seasons on infected wood.

The results of this trial and descriptions of the fungus and its biology were presented at a work shop and vineyard walk in December 2009.