An extensive study was conducted during 2007 and 2008 in three major tomato production areas of Cyprus, where Tomato yellow leaf curl virus (TYLCV) is commonly found, to assess the incidence and prevalence of naturally infected weed species that could serve as TYLCV reservoirs. Approximately 4,000 of the most common dicotyledonous plants belonging to 122 species from 25 families were collected, identified, and tested for TYLCV presence using serological and molecular methods. The tests included a previously reported conventional polymerase chain reaction (PCR) assay and a real-time TaqMan PCR assay developed and optimized in this study. Real-time PCR was found to be the most sensitive technique, and enabled the detection of TYLCV in 461 samples of 49 different species belonging to the families Amaranthaceae, Chenopodiaceae, Compositae, Convolvulaceae, Cruciferae, Euphorbiaceae, Geraniaceae, Leguminosae, Malvaceae, Orobanchaceae, Plantaginaceae, Primulaceae, Solanaceae, Umbelliferae, and Urticaceae. The results further indicated that the host range of TYLCV in Cyprus is far more extensive than previously documented and, therefore, new management strategies are required. These should focus on the control of alternative virus hosts during the growing season and in crop-free periods.

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In a survey during 2000–2002 to determine the identity and prevalence of viruses affecting cucurbit crops in Cyprus, 2993 samples of cucumber, zucchini, melon and watermelon were collected from the five major cucurbit‐growing areas in Cyprus. Zucchini yellow mosaic virus (ZYMV), Papaya ringspot virus type W (PRSV‐W), Watermelon mosaic virus (WMV), Cucurbit aphid‐borne yellows virus (CABYV), Cucumber mosaic virus (CMV) and Squash mosaic virus (SqMV) were detected by enzyme‐linked immunosorbent assay (ELISA), and Cucurbit yellow stunting disorder virus (CYSDV), Beet pseudo‐yellows virus (BPYV) and Cucumber vein yellowing virus (CVYV) by reverse transcription polymerase chain reaction (RT–PCR). ZYMV was the most prevalent virus of cucurbits in Cyprus with an overall incidence of 45%. PRSV‐W, CABYV and WMV were detected in 20.8%, 20.8% and 7.8% of the samples tested, respectively. CYSDV was detected in most greenhouse cucumber samples with yellowing symptoms (88.1%), whereas BPYV and CVYV were found in only 2.4% and 9.5%, respectively, of samples. CMV and SqMV were not detected in any cucurbitaceous crop during this survey.

The results of the study suggest that a high risk for selection of QoI-resistant strains exists in crops heavily treated with QoIs, in spite of the widespread occurrence of the cytb intron in B. cinerea populations. The developed real-time TaqMan PCR constitutes a powerful tool to streamline detection of the mutation by reducing pre- and post-amplification manipulations, and can be used for rapid screening and quantification of QoI resistance.

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