First report of Diplodia bulgarica causing black canker on apple (Malus domestica) and pear (Pyrus communis) in Germany

Hinrichs-Berger, J.; Zegermacher, Kamilla; Zgraja, Gabriele

doi:10.1002/ndr2.12004

Cited by 3 publications

(9 citation statements)

References 2 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diplodia bulgarica causes cankers on trunks and limbs, twig blight, gummosis, pre‐ and post‐harvest fruit rot, bark and vascular discoloration of infected shoots, dieback and tree decline (Abdollahzadeh, 2015; Hinrichs‐Berger et al., 2021; Nourian et al., 2021). As the infection develops, the bark separates from the underlying wood and falls to the ground, whereas the wood beneath it appears blackened and looks like charcoal.…”

Section: Pest Categorisationmentioning

confidence: 99%

“…Diplodia bulgarica has been reported from Bulgaria (Phillips et al., 2012) and Germany (Hinrichs‐Berger et al., 2021; Koch et al., 2022).…”

Section: Pest Categorisationmentioning

confidence: 99%

“…According to the German NPPO (March 2023), the pathogen was first reported causing black rot canker on apple ( M. domestica ) and pear ( P. communis ) in organic pome orchards in Baden‐Wuerttemberg (Hinrichs‐Berger et al., 2021). A large survey carried out during November 2021–September 2022 focusing on black rot canker symptoms in apple and pear orchards in 16 Federal States resulted in the detection of D. bulgarica in 137 out of 445 samples collected (31%).…”

Section: Pest Categorisationmentioning

confidence: 99%

“…(2020), Eken (2021), Hinrichs‐Berger et al. (2021), Zeynali Bari et al. (2021) Malus sylvestris RosaceaeWild applePhillips et al.…”

Section: Appendix a – Diplodia Bulgarica Host Plants/species Affectedmentioning

confidence: 99%

“…As the infection develops, the bark separates from the underlying wood and falls to the ground, whereas the wood beneath it appears blackened and looks like charcoal. In some cases, the trees are girdled by the cankers and die (Hinrichs‐Berger et al., 2021). The above‐mentioned symptoms are similar to those caused by other Diplodia species or other biotic (fungi, bacteria, etc.)…”

Section: Pest Categorisationmentioning

confidence: 99%

See 4 more Smart Citations

Pest categorisation of Diplodia bulgarica

Bragard¹,

Baptista²,

Chatzivassiliou³

et al. 2023

EFS2

View full text Add to dashboard Cite

The EFSA Plant Health Panel performed a pest categorisation of Diplodia bulgarica, a clearly defined plant pathogenic fungus of the family Botryosphaeriaceae. The pathogen affects Malus domestica, M. sylvestris and Pyrus communis causing various symptoms such as canker, twig blight, gummosis, pre‐ and post‐harvest fruit rot, dieback and tree decline. The pathogen is present in Asia (India, Iran, Türkiye) and in non‐EU Europe (Serbia). Concerning the EU, the pathogen is present in Bulgaria and widespread in Germany. There is a key uncertainty on the geographical distribution of D. bulgarica worldwide and in the EU, because in the past, when molecular tools were not available, the pathogen might have been misidentified as other Diplodia species (e.g. D. intermedia, D. malorum, D. mutila, D. seriata) or other members of the Botryosphaeriaceae family affecting apple and pear based only on morphology and pathogenicity tests. Diplodia bulgarica is not included in Commission Implementing Regulation (EU) 2019/2072. Plants for planting, other than seeds, fresh fruits, and bark and wood of host plants as well as soil and other plant‐growing media carrying plant debris are the main pathways for the further entry of the pathogen into the EU. Host availability and climate suitability factors are favourable for the further establishment of the pathogen in the EU. In the areas of its present distribution, including Germany, the pathogen has a direct impact on cultivated hosts. Phytosanitary measures are available to prevent the further introduction and spread of the pathogen into the EU. Diplodia bulgarica satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest.

show abstract

Section: Pest Categorisationmentioning

confidence: 99%

“…Diplodia bulgarica has been reported from Bulgaria (Phillips et al., 2012) and Germany (Hinrichs‐Berger et al., 2021; Koch et al., 2022).…”

Section: Pest Categorisationmentioning

confidence: 99%

Section: Pest Categorisationmentioning

confidence: 99%

“…(2020), Eken (2021), Hinrichs‐Berger et al. (2021), Zeynali Bari et al. (2021) Malus sylvestris RosaceaeWild applePhillips et al.…”

Section: Appendix a – Diplodia Bulgarica Host Plants/species Affectedmentioning

confidence: 99%

Section: Pest Categorisationmentioning

confidence: 99%

See 3 more Smart Citations

Pest categorisation of Diplodia bulgarica

Bragard¹,

Baptista²,

Chatzivassiliou³

et al. 2023

EFS2

View full text Add to dashboard Cite

show abstract

Diplodia bulgarica , the cause of canker disease in apple ( Malus × domestica ) in Türkiye

Eken,

Demir,

Çağlayan

2024

Archives of Phytopathology and Plant Protection

View full text Add to dashboard Cite

First Report of Diplodia bulgarica Causing Black Canker on Apple in California

Elfar,

Carachure,

Bustamante

et al. 2024

Plant Disease

View full text Add to dashboard Cite

California is the sixth largest apple-producing state in the United States with a production that reached 4,654 ha in 2021. During the late winter of 2023, black canker symptoms were observed on branches of ‘Gravenstein’ apple (Malus domestica) in two commercial orchards in Sonoma County, California. The prevalence of symptomatic trees ranged from 10 to 30%. External symptoms included charcoal looking-cankers with the bark peeling off from the primary and secondary branches. Internally, cankers were dark brown in color with a hard consistency. Pycnidia were observed on the surface of older cankers. Fungal isolations were performed from disinfected (70% ethanol, 30 s) symptomatic branch samples (n = 15). Small wood pieces (5 mm length) were taken from the margin of diseased and healthy tissues, and placed on potato dextrose agar acidified with 92% lactic acid at 0.5 mL per liter (APDA). Plates were incubated at room temperature (20-22 °C) for 7 days. Colonies of Botryosphaeriaceae species (Phillips et al. 2013) (n = 12) were consistently recovered and pure cultures were obtained by transferring a single hyphal tip onto fresh APDA. Colonies were light gray with irregular margins. To induce pycnidia formation, two isolates (UCD11350 and UCD11351) were grown on pistachio leaf agar for 21 days. Conidia (n = 50) were thick-walled and ovoid in shape, initially hyaline, then turned pale brown and dark brown at maturity, and some of them became 1-septate, ranging from 18.9 to 24.0 (21.9) × 11.5 to 14.7 (13.4) µm. Isolates were identified by sequencing a partial region of the beta-tubulin (tub2) gene using the primers Bt2a/Bt2b (Glass and Donaldson 1995). BLAST searches on NCBI GenBank revealed 99.5 % identity with the Diplodia bulgarica ex-type (CBS 1245254). To confirm the identity, the rRNA internal transcribed spacer (ITS) and the translation elongation factor 1-alpha (tef1) were also sequenced using ITS5/ITS4 (White et al. 1990), and EF1-688F/EF1-1251R (Alves et al. 2008), respectively. A maximum parsimony multi-locus phylogenetic analysis clustered Californian isolates with reference strains of D. bulgarica. Sequences were deposited in GenBank (nos. OR631209 to OR631210, OR637361 to OR637362, OR637363 to OR637364 for ITS, tub2, and tef1, respectively). Pathogenicity tests were conducted on 2 to 3-year-old branches (n = 5) of over 20-year-old trees by inserting a 5-mm segment of a toothpick, completely colonized with each of the two isolates mentioned above, into a 1-mm-diameter hole made with a sterile drill bit. The same number of branches where mock inoculated with a non-colonized toothpick as negative control. The experiment was performed twice. After ten weeks, inoculations resulted in dark brown necrotic lesions that ranged from 54.0 to 59.8 mm in length. Negative controls remained asymptomatic. Koch's postulates were fulfilled by successfully recovering the isolates from the lesion margins, which were confirmed by morphology. Diplodia bulgarica was first described affecting M. sylvestris in Bulgaria (Phillips et al. 2012), and then detected on M. domestica causing cankers in Iran (Abdollahzadeh 2015), India (Nabi et al. 2020), Germany (Hinrichs-Berger al. 2021) and Türkiye (Eken 2021). The pathogen was also identified causing postharvest fruit rot (Eken 2022). To our knowledge, this is the first report of D. bulgarica causing branch canker on apple in California, which provides important information for developing detection and control strategies.

show abstract

First report of Diplodia bulgarica causing black canker on apple (Malus domestica) and pear (Pyrus communis) in Germany

Cited by 3 publications

References 2 publications

Pest categorisation of Diplodia bulgarica

Pest categorisation of Diplodia bulgarica

Diplodia bulgarica , the cause of canker disease in apple ( Malus × domestica ) in Türkiye

First Report of Diplodia bulgarica Causing Black Canker on Apple in California

Contact Info

Product

Resources

About