Figure 1. Inoculation method for following the early infection process.

A piece of sunflower hypocotyl and an agar plug with actively growing mycelium of S. sclerotiorum were placed at a distance of about 1 mm in a Petri dish with wet filter paper. A: Aerial mycelium developed and when prospecting hyphae came in contact with the host surface dome-shaped infection cushions (arrows) developed at 12–24 hpi. B: Detail of Figure 1A; prospecting hyphae (hy) of the aerial mycelium with water droplets and two infection cushions (cu).