Agens koji je izoliran cijepljenjem iz pitospora [Pittosporum tobira (Thunb.) Ait] bez panašire

Abstract

A pathogen, transmissible by means of bark grafting, has been isolated from Pittosporum tobira plants showing dendritic-like vein clearing, yellowish chlorotic spots, leaf roll, terminal rosettes and leaf deformation symptoms. The material has been found and collected around Dubrovnik and the Peninsula of Lapad at the Yugoslav seashore. This disease is somewhat similar symptomatologically to the vein clearing virus disease of Pittosporum. Nevertheless, the pathogen isolated by us could not be transmitted mechanically. Further investigations are required in order to solve the question of whether Pittosporum vein clearing disease, Pittosporum variegation disease, and Pittosporum dendritic vein yellowing disease — a name proposed for the disease described here — are caused by the same pathogen, and to establish the virus or mycoplasma nature of these pathogens. According to our preliminary observations, leafhopper species (not yet identified), which occur on Pittosporum tobira in a large number, play a possible role in the spread and distribution of the pathogen. Main aims of further investigations in this field are the identification of possible insect vectors, determination of mode of transmission of the pathogen, as well as host range studies.Pomoću cijepljenja korom izoliran je iz vrste Pittosporum tobira patogeni agens koji je na toj biljci uzrokovao simptome u obliku prosvjetljivanja žila nalik na dendrite, žućkastih klorotičnih pjega, uvijanja lista, stvaranja vršnih rozeta i deformacija lista. Materijal je sakupljen na obali oko Dubrovnika i poluotoka Lapada. Ta bolest, koju sam ovdje opisao, po simptomima ponešto nalikuje na virusnu bolest prosvjetljivanja žila pitospora, proučenu i opisanu već ranije (Corte 1957). Međutim, patogeni agens nismo mogli prenijeti mehaničkom ino- kulacijom. Potrebna su daljnja istraživanja da se riješi pitanje da li isti uzročnik izaziva bolest prosvjetljivanja žila pitospora, bolest šarenila pitospora (Brierley 1944) i bolest dendritskog žućenja žila pitospora. Posljednji naziv predlažem za bolest koju sam ovdje opisao. Isto tako trebalo bi raščistiti pitanje da li je uzročnik virus ili mikoplazma. Prema mojim prethodnim istraživanjima na širenje uzročnika vjerojatno utječu neke vrste cvrčaka; te vrste nisu još identificirane, a vrlo su česte na pitosporu