Multinucleate Rhizoctonia sp. a pathogen of Chrysanthemum

Abstract

Potted chrysanthemum plants (Chrysanthemum Indicum Groep, sin. Chr. x grandiflorum) originating from Mala Pruga, Zemun Polje, exhibited a variety of symptoms including stem and leaf necrosis, as well as bud and flower rot. Necrosis started on stems, which were previously cut in order to provoke flowering. Further on, necrosis spread and covered larger plant areas, and after a period of three weeks killed the plants. From diseased plants fungal isolates were obtained which proved to be pathogenic to healthy stems of chrysanthemum. According to macroscopic and microscopic as well as some biological properties the causal agent of chrysanthemum stem necrosis was identified as multinucleate Rhizoctonia sp. (Rhizoctonia solani).

Na saksijskim biljkama hrizanteme (Chrysanthemum Indicum Groep, sin. Chr. x grandiflorum) sa lokaliteta Mala Pruga, Zemun Polje, uočeni su simptomi u vidu sužavanja i nekroze stabljika, sušenja pupoljaka, cvetova i listova. Nekrotični proces započeo je na mestima gde su stabljike sečene u cilju provociranja obimnog cvetanja biljaka. Odatle, nekroza se širila da bi posle tri nedelje od pojave prvih simptoma zahvatila čitavu biljku. Iz obolelih stabljika izolovana je gljiva čija je patogenost potvrđena veštačkim inokulacijama zdravih stabljika hrizanteme. Na osnovu morfoloških (makroskopskih i mikroskopskih) i bioloških odlika, fitopatogena gljiva prouzrokovač nekroze hrizanteme, identifikovana je kao višejedarna Rhizoctonia sp.(Rhizoctonia solani).