Pathogenicity of Phytophthoraspecies to ornamental plant Plectranthus scutellarioides

Pathogenicity of seven Phytophthoraspecies (P. plurivora, P. citricola, P. lacustris, P. gonapodyides, P. chlamydospora, P. pseudocryptogeaand P. hydropathica) to ornamental plant Plectranthus scutellarioideswas evaluated. Susceptibility of the tested plant to the selected pathogens was analyzed by a baiting technique with detached leaves and an infection of cuttings. P. pseudocryptogeawas determined as the most aggressive pathogen to the coleus plant according to the results of both methods. P. lacustris, P. gonapodyides, P. chlamydosporaand P. hydropathicainduced comparable disease symptoms on tested leaves as well as cuttings. P. plurivoraand P. citricolademonstrated less aggressiveness to leaves of P. scutellarioides, but strongly inhibited the growth of the roots of the cuttings. All tested Phytophthoraspecies were recognized as a real threat for coleus plants in their natural habitat, but they could also compromise its cultivation in greenhouses, nurseries and parks. In addition, the ability of the fungicide azoxystrobin for an effective control of Phytophthoraspecies was proved.