The Australian downy mildew simulator identified many false positive infection periods and may need modifying for Marlborough conditions. As no disease was detected, no sprays were applied from six weeks after bud burst. The absence of downy mildew disease may be attributed to extremely low levels of primary inoculum because of rigorous spray programmes in previous years. Powdery Mildew Wetness is not a prerequisite for powdery mildew infection. There was no difference between the standard and target treatments.
Powdery mildew is an inoculum-driven disease, ie.
Thus it is important to reduce the carry-over of primary inoculum from one season to the next. This can be achieved by controlling disease levels within a season. This includes the correct identification of disease, knowledge of crop phenology along with the stages that it is susceptible to different diseases and weather monitoring. For a disease management system to be most effective, information should be specific to each vineyard. Managed correctly, the disease management system will reduce the number of fungicides required on the vineyard thus saving the grower time and money.