Development of a dot immunobinding assay to detect Phytophthora spp. in naturally dark‐rooted woody plants

Summary An indirect dot immunobinding assay (DIBA) with a PAb raised against an isolate of P. cinnumomi was evaluated to detect Phytophthora spp. in naturally dark‐rooted woody plants. Screening of different modifications of the procedure were done with root samples of Chamaecyparis lawsoniana non‐infected and infected with P. cinnamomi. With the optimised DIBA procedure, root infection could be diagnosed by a clearly defined halo around the spot and by a colour change in the spot using Fast Red or Fast Blue substrate. Detection of different Phytophthora species in Chamaecyparis plants from commercial nurseries was successful with the optimised procedure.