Detection of viruses in olive trees in Croatian Istria

Abstract

Following identification of four viruses in a general survey of olive trees throughout Croatia, a detailed survey was conducted in 2009 in the field collection of the Institute of Agriculture and Tourism in Poreč (an important reservoir of Istrian native olive germplasm) in order to evaluate the sanitary status of the most important Croatian Istria olive cultivars. Twenty five samples from symptomatic or symptomless trees were collected from five autochthonous and four exotic cultivars. All the samples were tested by RT-PCR for the presence of: Olive leaf yellowing associated virus (OLYaV), Cherry leaf roll virus (CLRV), Strawberry latent ring spot virus (SLRSV), Arabis mosaic virus (ArMV), Olive latent virus-1 (OLV-1), Cucumber mosaic virus (CMV), Olive latent virus-2 (OLV-2) and Tobacco necrosis virus D (TNV-D). Six of the 25 plants were found positive to CLRV; all infected plants showed leaf and fruit deformation and leaf yellowing. Four positive samples were from the native cv. Buža whereas the other two were from two exotic cultivars: Ascolana tenera and Frantoio. The presence of CLRV,  either in native or imported plants, highlights the importance of strict phytosanitary regulations to prevent incursion of key virus diseases.