Scientific and Technological Objectives

The relationships between tasks of different Workpackages are illustrated in graphical presentation for research on downy mildew of grapevine and scab in apple.

Development of potentiators of resistance and organically based fungicides (Workpackage 4)

Potentiators of resistance and organically based fungicides suited for organic grapevine and apple production under European conditions will be screened for control of Plasmopara viticola in grapevine by WBI DE and FiBL CH and control of Venturia inaequalis in apple by U. Copenhagen, former U Copenhagen DK (former KVL) and U Aarhus DK (former DIAS). Timing and application and formulation methods for potentiators and organically based fungicides in grapevine and apple will be improved. For all candidate compounds, the economic feasibility of mass production and possible environmental risks will be assessed in an early stage during the screening process.

Development of novel biocontrol agents against Plasmopara viticola and Venturia inaequalis (Workpackage 5)

The effect of micro-organisms isolated from Plasmopara viticola infected crop residues of grapevine on the viability of Plasmopara viticola oospores will be tested and efficient antagonists will be selected by PRI NL. Endophytic and epiphytic micro-organisms will be isolated from green and senescing apple leaves. The effect of application of micro-organisms to scabbed leaves on ascospore production of Venturia inaequalis and leaf decomposition will be assessed. Hyperparasites of Venturia inaequalis obtained from infected apple foliage will be isolated and identified by PRI NL and U Copenhagen DK (former KVL). The possible role of hyperparasites in reducing Venturia inaequalis conidial sporulation and ascospore production will be assessed.
For all candidate antagonists economic feasibility of mass production and possible environmental risks will be assessed in an early stage during the screening process by PROPHYTA DE.

Components for Integrated Management Systems (Workpackage 6)

The selection pressure of potentiators of resistance and organically based fungicides and forced evolution on Plasmopara viticola in grapevine will be quanitied under controlled conditions and in the field by ETHZ CH. The obtained knowledge will be used to minimise risks of forced evolution of Plasmopara viticola in response to novel control measures and resistant cultivars in grapevine to ensure sustainability of novel control measures.
In apple orchards, the effect of cultural practises on micro-organisms naturally present on or in green and senescing leaves and their interaction with Venturia inaequalis ascospore production will be identified by PRI NL. Methods will be developed by PPO NL to increase earthworm populations and their ability to decompose leaves as ascospore source of Venturia inaequalis. Stimulating naturally occurring micro-organisms and earthworms will lead to enhanced leaf decomposition and suppression of Venturia inaequalis ascospore production.

Integration of different control measures to maximise disease control of Plasmopara viticola in organic grapevine and of Venturia inaequalis in organic apple production (Workpackage 7)

Field experiments will be carried out, combining known control measures incl. ‘pipeline’ products and control measures developed by REPCO. ECOVIN DE and BIOFRUITADVIES NL will advice in the choice of control measures to be tested and will dessimate results to organic growers.
Experiments in grapevine on control of Plasmopara viticola will be carried out by IASMA IT and GRAB FR in experimental and practical organic vineyards. Copper alternatives will be compared with untreated and copper fungicides. Disease severity of Plasmopara viticola will be recorded and microvinification including sensory analysis will be performed.
Experiments in apple on control of Venturia inaequalis will be carried out by PPO NL in an experimental organic orchard. Combined applications of control measures to leaves in autumn will be directed at the reduction of ascospore production. The results of the treatment schedules are examined by counting ascospores produced in spring. In other field experiments, applications will be directed on the summer epidemics with applications of potentiators of resistance, organically based fungicides and possibly hyperparasites. Scab infections on leaves and fruits will be assessed.