First Report of Diplodia pinea on Pseudotsuga menziesii in Turkey

Abstract

and Bt2a/Bt2b, respectively (2). The DNA sequences of fungal isolates from California showed 99 to 100% homology with the ex-type Diplodia seriata De Not. (1) CBS 112555 deposited in GenBank. DNA sequences from three California isolates were submitted to GenBank with accession numbers KC937062, KC937065, KF481957, KF481598, KF481959, and KF481960. Pathogenicity tests were performed in March 2011 on 3-yearold Bartlett pear trees planted at an experimental farm in Davis, CA. A single, circular, 2-cm pruning wound at the top of the trunk was inoculated on each of three single-tree replications using 2-cm mycelial plugs from 14-day-old colonies growing on PDA. After inoculation, mycelial plugs were covered and sealed with Parafilm and aluminum foil for the duration of the trial. Three control trees were inoculated using sterile PDA plugs. Twelve months after inoculation, UCD103 and UCD105 were consistently re-isolated from the margin between necrotic and healthy tissue using the same methods described for the original isolation, and UCD102 was reisolated in two out of three plants. The average lesion lengths of UCD102, UCD103, UCD105, and control plants were 12.5, 17.3, 23, and 1 mm, respectively. Control lesions were short and sterile, and .seemed to be a physiological reaction from the plant. A second pathogenicity test was completed in 5 months beginning in June 2012. UCDI05 was consistently re-isolated, and UCD102 and UCD103 were re-isolated in two out of three plants. The average lesion lengths for UCD102, UCD103, UCD105, and control plants were 2, 3, 5, and 1 mm, respectively. Compared to grapevine (Vitis vinifera), the pathogen grows more slowly in pear tissue under natural conditions. To our knowledge, this is the first report describing D. seriata as a causal agent of pear branch canker in California. Canker diseases can reduce the lifespan of perennial plants, ultimately leading to long term economic losses for growers (3).Since 2010, a new foliar and fruit disease was observed in pomegranate {Púnica granattim L.) orchards in Alicante Province (eastern Spain). Symptoms included black spots on leaves and fruits, as well as chlorosis and premature abscission of leaves. Fungal isolates were obtained by surface-disinfecting small fragments of symptomatic leaf and fruit tissues in 0.5% NaOCl, double-rinsing in sterile water, and plating them onto potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate. Gray-to-black colonies were obtained, which were identified as Alternaria sp. based on the dark, brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (4). Conidia {n = 100) measured (12.2-) 20.2 (-27.6) x (5.7-) 9.2 (-12.0) um, and had 3 to 6 transverse and 0 to 5 longitudinal septa. Single spore cultures were obtained and their genomic DNA was extracted. The internal transcribed spacer (ITS) region of rDNA and partial sequences of the beta tubulin gene were amplified and seque...

New and unexpected host associations for Diplodia sapinea in the Western Balkans

“…This could have lead to an increase in pathogen pressure (Ennos, ) which, along with the above‐mentioned stress factors, allowed D. sapinea to cross‐infect nearby ornamentals. High propagule pressure and geographical proximity have also been hypothesized to be the cause of the outbreaks of D. sapinea in a P. menziesii plantation in Turkey (Kaya, Lehtijärvi, Kaya, & Dogmus‐Lehtijärvi, ) and in nurseries of pine species in the USA and South Africa (Bihon et al., ; Palmer & Nicholls, ; Stanosz et al., ).…”

The pine pathogen Diplodia sapinea is associated with the death of large Douglas fir trees

“…Diplodia sapinea has previously been shown to be pathogenic towards very young Ps. menziesii (Kaya et al, 2014;Zlatković et al, 2017), but our study reports for the first time that this pathogen has the potential to kill older and larger Douglas fir trees as well. Post-mortal infection by D. sapinea is unlikely because the trees died recently and did not show root rot, infections by other pathogens or attacks by bark beetles or other insects that could have contributed to their death.…”

Occurrence and genetic similarity of Diplodia pinea on shoots and cones in seed orchards of Pinus spp. in north-western Turkey

“…The pathogen was noted on dead twigs and canker samples of P. elderica and P. brutia in Kahramanmaraş in 2005. Several years later it was found on Pseudotsuga menziesii in İzmit province (Kaya et al 2014). Studies carried out in the western part of the Taurus Mts.…”