Susceptibility of different prunus rootstocks to natural infection of plum pox virus-Turkey (PPV-T) in Central Anatolia

Sharka is the most damaging viral disease of Prunus spp. and the causative agent is plum pox virus (PPV). PPV is widespread and poses a serious problem in stone fruit crops in Turkey. A unique strain of PPV has so far been identified in Turkey and called as PPV-Turkey (PPV-T). The aims of the present study were to describe the efficiency of PPV-T transmission via aphids and to identify the susceptibility of different Prunus rootstocks against PPV-T strain under natural inoculum in Kayseri province located Central Anatolia Region of Turkey. This experiment was established in a small residential orchard where PPV-T infected apricot and plum trees were detected. Five different Prunus rootstocks from which 200 individuals were planted in PPV-T infected orchard and experiment was designed in a randomized complete block desing with 10 replications per block. All rootstocks were regularly tested by DAS-ELISA and RT-PCR during 2015–2017. The results showed that the most susceptible rootstocks in terms of PPV-T infection were Nemaguard, Myrobalan 29B and Myrobalan 29C with the infection rate of 3.61%, 2.74% and 1.04%, respectively. On the other hand, GF677 and Garnem were never found infected with PPV-T. Aphis gossypii, A. craccivora, A. spiraecola, Brachycaudus helichrysi, Hyalopterus pruni, Myzus persicae, Macrosiphum euphorbiae were detected as most abundant aphid species in experimental plot. In 2015, the highest percentage of viruliferous aphids was found as A. gossypii (100%), followed by B. helichrysi (77.8%), A. spiraecola (55.72%), M. persicae (46.05%) and H. pruni (30.76%) whereas it was 100% for A. gossypii and M. euphorbiae followed by A. spiraecola (76.32%), M. persicae (73.1%), H. pruni (62.06%) and B. helichrysi (61.53%) in 2016 by squash real time RT-PCR. The present study showed that PPV-T was effectively transmitted by different aphid species in natural conditions in Kayseri district. It was concluded that Nemaguard and Myrobalan which were found to be the most sensitive rootstocks to PPV-T should not be preferred by growers as Prunus rootstock where PPV poses a high risk.