INCIDENCE OF VIRUSES ON AUTOCHTHONOUS AND INTRODUCED OLIVE VARIETIES IN CROATIAN ISTRIA DETECTED BY THREE DIAGNOSTIC TECHNIQUES.

A survey on viruses infecting olive trees was performed in Croatian Istria. Major olive viruses were detected using molecular (RT-PCR), biological (bioassay on indicator plants) and serological (DAS-ELISA) diagnostic techniques. Specifically, fifteen olive varieties from a total of 62 olive trees have been tested for the presence of eight viruses. Cherry leaf roll virus (CLRV), Strawberry latent ring spot virus (SLRSV) and Olive latent virus-1 (OLV-1) were detected by one-step RT-PCR in ten autochthonous and five introduced olive varieties. The most frequent found was CLRV, detected in 11.3% of tested trees both in autochthonous and in introduced varieties, while OLV-1 and SLRSV were detected only in autochthonous varieties and in lower incidence. In order to confirm the results obtained by one-step RT-PCR, inocula prepared from the flowers were used for inoculation of herbaceous indicator plants. Symptoms on herbaceous hosts were monitored and CLRV and SLRSV were detected by DAS-ELISA, confirming the results of molecular test. The most successful mechanical transmission was on Chenopodium quinoa, while the most evident symptoms were observed on Cucumis sativus L. cv. Sunčani potok plants. [ABSTRACT FROM AUTHOR]