MICROORGANISMS FOR HEALTHY VINE

Biocontrol of downy mildew

Picture: Günter Brader, AIT

Picture: Christina Morauf, SAN Agrow

Picture: Christina Morauf, SAN Agrow

Downy mildew of grapevine is a disease caused by the Oomycete Plasmopara viticola, which can result in massive damage up to complete crop loss. An outbreak of downy mildew depends on weather conditions and can affect leaves, young twigs and fruits. To combat downy mildew, a number of fungicides and copper salts are used, both with problematic effects on the environment. The application is preventive, an outbreak itself can only be controlled with great difficulty. The approval of a number of substances, which are effective against downy mildew will expire in the near future and further registration will be viewed critically across Europe due to the effects on the environment.

European vine varieties are mostly sensitive to downy mildew infection, while American grapevines are more tolerant. One reason for that is that a crucial step in the infection cycle is the entry of flagellated zoospores into the stomata of the plant, which happens more frequently in the European varieties. Eliminating this step of the infection cycle reduces the problem.

In the present project we are investigating yeasts and bacteria for their ability to colonize leaf surfaces and stomata and thus or through interference prevent zoospores from infection. For biocontrol applications there are also substances of natural origin that can induce resistance to fungal diseases. Here, microorganisms with the novel mechanisms of action as well as resistance-inducing substances are to be tested for their compatibility and combined applications in vines are to be tested for their effectiveness against downy mildew.

Ultimately, the project aims to achieve new sustainable ways of controlling downy mildew in grapevine, with the long-term goal of achieving similar applications in other diseases caused by oomycetes (e.g. late blight of potatoes).

Lead Researcher:

Dr. Günter Brader

Senior Scientist / Bioresources
Department Bioresources (AIT)

guenter.brader@ait.ac.at
+43 50550-3650
www.ait.ac.at