ISHS Acta Horticulturae 754: International Workshop on Advances in Grapevine and Wine Research
BIOLOGICAL CONTROL OF PLASMOPARA VITICOLA: A MULTISITE APPROACH |
| Authors: | A. Vecchione, L. Zulini, I. Pertot, R. Musetti |
| Keywords: | organic viticulture, downy mildew, copper replacement, biocontrol agents, Vitis vinifera |
| Abstract:
In organic viticulture Plasmopara viticola control is mainly based on copper. The expected restrictions in the European Union on copper in organic agriculture stimulated the research of alternatives and the optimisation of copper use. The reduction of copper can be achieved by alternatives such as biocontrol agents (BCAs), natural products or formulations that allow lower dosages of copper maintaining an adequate efficacy against the disease. Peptidates of copper are as efficacious as traditional copper formulation at ¼ of the rate, however in particular circumstances such low rate can shows phytotoxic effects. BCAs used singly are often not able to control sufficiently P. viticola. For this reason an approach to control P. viticola by interfering at different stages of its life cycle with strategies combining the various alternatives, seems more promising. We initiated a screening of bacteria, yeast and other fungi isolated from plant and soil materials for activity against P. viticola oospore germination, and inhibition of sporangiophore production on infected leaf disk. We identified 5% of the 1,764 microorganisms having oospore germination inhibiting capacity and only 0.8% inhibiting sporangiophore production. In our work we performed different trials to test the effectiveness of a large amount of products and potential BCAs against P. viticola in controlled conditions and field trials. Most of the natural product has low efficacy with high disease pressures and high costs. BCAs are active only for a short time after application and if they act as resistance inducers they are not able to completely control the disease. We conclude that only a strategy oriented at controlling P. viticola at multiple site and stages of it life cycle using BCAs or alternative products, can successfully and reliably avoid P. viticola damages. | |
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