Three drops (each app. 30 μl) of a Plasmopara viticola
sporangia suspension were added to the abaxial leaf surfacesurface
at three intersections of main veins of each leaf covering
an area of approximately 0.5 cm2. Control plants were
treated with 30 μl of tap water in place of the sporangia
solution in the same configuration as for the inoculum on
treated plants. Plants were covered over night with wet
polyethylene bags. After 12 h the bags were removed and
infrared images were taken every 24 h. On day eight, plants
were kept in a darkened moist chamber over night at 100 %
relative humidity to induce the sporulation of Plasmopara
viticola