Together for the Better: Improvement of a Model Based Strategy for Grapevine Downy Mildew Control by Addition of Potassium Phosphonates.

Gottfried Bleyer,Stefan Schumacher,Fedor Lösch,René Fuchs

doi:10.3390/plants9060710

Abstract

Grapevine downy mildew is one of the major diseases in viticulture. To control this disease, a more effective strategy has been developed and established based on growth and model data as well as on a combination of fungicides. For this purpose, the systemic plant protection product potassium phosphonate (PP) was combined with two contact fungicides. Treatments were carried out according to the different experimental conditions after the growth of 400 cm2, 600 cm2, and 800 cm2 leaf area per primary shoot. PP increased the effectiveness of the preventive fungicides whenever high infection pressure was the case. The experiments also show that it is possible to extend the treatment intervals from 400 cm2 to 600 cm2 new leaf area when PP was added. However, none of the tested treatments were sufficient for the extension to intervals of 800 cm2. These data show that PP can be a key factor in the reduction of the application of synthetic or copper-based fungicides.

Highlights

Grapevines are grown on approximately 7.4 million hectares of land worldwide [1]
Most of this area is cultivated with Vitis vinifera L. which has been used for human consumption for more than 5000 years [2]
The results of this study show that PP can improve the effect of contact fungicides and that it could be an important option to ensure yields in organic farming in the event of a possible re-approval

Summary

Introduction

Grapevines are grown on approximately 7.4 million hectares of land worldwide [1]. Most of this area is cultivated with Vitis vinifera L. which has been used for human consumption for more than 5000 years [2]. More than 10,000 cultivars of Vitis vinifera are known, which have been developed through natural crossings, somatic variation events, and breeding, but only 2500 are used for wine production or direct consumption all over the globe [3]. Since P. viticola and V. vinifera developed on different continents and were mutually exposed just 150 years ago [5], the plants were never challenged to develop any defenses against this pathogen during evolution [6].

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