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    First report of shoot blight and branch canker of Pyrus communis by Neoscytalidium novaehollandiae in Turkey
    (SPRINGERONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2021) Oksal, E; Ozer, G
    Turkey is the world’s fifth-largest pear (Pyrus communis L.) producer with a production of 503.000 tons and a cultivated area of 26.000 ha (FAOSTAT 2020). In June 2019, symptoms of shoot blight and branch canker showing intensely dark wood discoloration, and dieback were observed on about 10% of pear trees (cv. Deveci) in two commercial orchards, 70 km away from each other in Battalgazi (38.466659 N 38.343073E) and Doğanşehir (38.085506 N 37.896307E) districts in Malatya province, Turkey. Small pieces of symptomatic tissues (5–10 mm2) were excised from symptomatic tissues of stems/branches and subjected to surface disinfection by immersing them in 1% NaOCl for 1 min and in sterile water twice. Pieces of tissues were then plated onto potato dextrose agar (PDA). Finally, four isolates were obtained after an incubation period at room temperature for five days and purified on PDA. The isolates were developed as dark gray to black with abundant arthroconidia in aerial mycelia. Arthroconidia (n?=?50) were thick-walled, 0 to 1 septate, rod-shaped, 5.1 to 9.7?×?3.1 to 4.6 ?m, and formed singly or in arthric chains. Pycniospores (n?=?50) produced on pine needles on 1.5% water agar were hyaline, ellipsoidal, 0–1-septate, 2.9 to 4.2?×?11.9 to 14.3 ?m. These morphological characteristics were consistent with the description of Neoscytalidium spp. by Phillips et al. (2013). The internal transcribed spacer (ITS) and the large subunit (LSU) of rDNA, and the translation elongation factor 1-? (EF1a) gene for a representative isolate (Mlty_01) were sequenced (GenBank accession Nos. MT041243, MT038898, and MT710710), and comparisons with those of Neoscytalidium novaehollandiae Pavlic, T.I. Burgess & M.J. Wingf. strain WAC12693 (EF585538, EF585551, and EF585576) showed 99–100% nucleotide identity for ITS, LSU, and EF1?, respectively. To confirm the pathogenicity of the isolate, five 2-year-old branches of pear cv. Deveci were wounded by removal of a plug of tissue with a depth of 2-mm and a 5-mm diameter cork borer and inoculated by 5-mm mycelial plugs from one-week-old culture. Sterile mycelial plugs were used as controls. Inoculated branches were immediately transferred to a growth chamber at 24 °C in a 12-h photoperiod. After one-month, necrotic lesions were observed on all inoculated branches, while all controls remained healthy. The fungus was re-isolated from lesions successfully. To our knowledge, this is the first report of shoot blight and canker on pear trees by N. novaehollandiae in Turkey and worldwide (Farr and Rossman 2020).
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    First report ofNeoscytalidium dimidiatumcausing shoot blight, dieback and canker of apricot in Turkey
    (SPRINGERONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2020) Oksal, E; Yigit, T; ozer, G
    Turkey is the largest apricot (Prunus armeniaca L.) producing country worldwide with almost 17 million trees producing fruits (TUIK 2019). In June 2018, shoot blight, branch dieback and canker symptoms were observed on about 9% apricot trees in the orchards examined in Malatya province (Turkey), which is alone responsible for 15.8% of world production of apricots. Symptomatic tissues were excised from stems and branches of diseased trees and superficially disinfected with 2% sodium hypochlorite for 2 min, twice rinsed, and air dried. The pieces were placed into Petri dishes containing potato dextrose agar (PDA) and incubated at 25 °C in the dark for 7 days. A total of 17 isolates were identified as Neoscytalidium-like based on macro- and micro-morphological characteristics of colonies. The colonies developed a dark green color. Conidia formed as arthric chains from mycelia were dark brown, thick-walled, 6.7 to 11.7?×?2.4 to 4.6 ?m (n?=?50), ovate to rectangular and observed to have 0- to 1-septa (Phillips et al. 2013). Pycnidia emerged on pine needles in the culture were stromatic, immersed, and dark brown to black. The internal transcribed spacer (ITS), the translation elongation factor 1-? gene (EF1-?), the ?-tubulin gene (BT2), and the large subunit of rRNA (LSU) gene sequences from a reference apricot isolate of Neoscytalidium sp. (Kale4-C) were amplified, sequenced, and deposited in the GenBank database (Accession Nos. MK788362, MK803351, MK803352, and MK803393, respectively). A BLASTn search of the resultant sequences showed 99.35–100% sequence homology with those of Neoscytalidium dimidiatum (Penz.) Crous & Slippers strain CBS 145.78 (ITS MH861121, EF1-? KF531795; BT2 KF531796; LSU DQ377922). Pathogenicity tests conducted by inoculating 2-year-old branches with 5-cm mycelial plugs of the reference isolate. Plugs were placed in wounds made with a sterile blade in the inner bark of plant branches. Non-colonized agar plugs were used as control. Inoculated and control branches were maintained in a growth chamber at 25 °C in a 12-h photoperiod. After three weeks, dark-brown discoloration was observed on all inoculated branches, whereas all controls remained symptomless. The fungus was re-isolated from lesions successfully to fulfill Koch’s postulates. To our knowledge, this is the first report of N. dimidiatum causing shoot blight, dieback and canker of apricot in Turkey (Farr and Rossman 2019).