Dual culture bioassay showing a colonized strip of Trichoderma spp. overlaid
on V8 agar colonized by Phytophthora ramorum (A). Every week, a 1 cm by 4.5 cm
strip was removed, divided in half (a, b) and cut into nine (1–9) 0.5 cm plugs (B),
which were placed either on Rhododendron ‘‘Cunningham’s White’’ leaf disks (C) or
on V8 agar supplemented with benomyl (D).