Pathogenicity of Diaporthe spp. on two blueberry cultivars (Vaccinium corymbosum)

Abstract

Diaporthe vaccinii causes twig blight and fruit rot and is currently listed as a quarantine organism for the European Union. In the Netherlands, two species from the same genus, Diaporthe eres and Diaporthe rudis, are regularly isolated from blighted twigs of Vaccinium corymbosum. This study compared the pathogenicity of these two species to D. vaccinii. To develop a pathogenicity test a field experiment was performed at an experimental station, testing isolates of D. rudis and D. eres. Most of the isolates tested did not cause statistically significantly larger lesions compared to the control treatment (P > 0.05). In a greenhouse experiment a similar test was conducted, comparing D. vaccinii with the closely related species D. eres. Two cultivars of blueberry, Duke and Liberty, were inoculated using two D. vaccinii and two D. eres isolates. Stem canker lesions caused by D. vaccinii were larger than these caused by D. eres isolates. The majority of the lesions caused by D. vaccinii did not pass the first node of the inoculated shoot, which might be an explanation for the ‘mild’ symptoms of D. vaccinii in V. corymbosum, which appear not to cause crop losses. The results of this study suggest that D. vaccinii may not be a major threat to blueberry production in Europe. Further data is required to be able to conclude whether the quarantine status of D. vaccinii is still appropriate.

Using Genealogical Concordance and Coalescent-Based Species Delimitation to Assess Species Boundaries in the Diaporthe eres Complex

“…Recognizing it as a synonym of D. eres means that its status as a major pathogen of blueberry would need to be reassessed. Previous studies [ 82 ] have suggested that D. vaccinii is probably not a major threat to blueberry production in Europe and that its status as a quarantine organism should be reappraised.…”

The bud rot pathogens infecting cannabis (Cannabis sativa L., marijuana) inflorescences: symptomology, species identification, pathogenicity and biological control

“…Traverso) was recovered from a hemp stem canker located near a blueberry field. These Diaporthe species are reported to infect a broad range of host plants, including blueberry (Lombard et al 2014;Cardinaals et al 2018), apple (Ali et al 2020), blackberry (Vrandecic et al 2011), grapevine (Baumgartner et al 2013;Lawrence et al 2015;Manawasinghe et al 2019), peach (Thomidis and Michailides 2009), pear (Bai et al 2015), plantago (Gomes et al 2013), spruce trees (Sakalidis et al 2021) and cranberry (Michalecka et al 2017). They are considered to be opportunistic pathogens causing root and fruit rots, dieback, cankers, leaf spots, blights, decay and wilt and also occur in plants as endophytes (Udayanga et al 2011(Udayanga et al , 2014Gomes et al 2013).…”

Diversity and Pathogenicity of Diaporthe Species Revealed from a Survey of Blueberry Orchards in Portugal

“…Although production initiated intensively only in 2011 with a yield of 700 tons and a cultivated area of 75 ha, in 2019 the country was ranked as the 9th largest producer worldwide [5], with a production of 15,418 tons, occupying a total area of 2490 ha [6], making it a highly profitable crop to the economy of the country. However, due to the spread of blueberry plant material across continents, it is expected that several fungal pathogens may affect blueberry orchards, given their entry into new habitats [7]. Some of these pathogens, such as members of Botryosphaeriaceae, Pestalotiopsis sensu lato and Diaporthe can cause twig blight, stem cankers and dieback on blueberry plants [8][9][10].…”

“…Members of this genus were previously found to colonize blueberry tissues as latent pathogens or endophytes [8] and as pathogens causing numerous diseases on this crop such as apical necrosis of twigs and stems, cankers, necrosis of the vascular tissues, wilting of leaves, and leaf spots [7,17,18]. These symptoms have been associated with an assemblage of species comprising D. ambigua, D. amygdali, D. australafricana, D. baccae, D. crousii, D. eres, D. foeniculina, D. oxe, D. passiflorae, D. phillipsii, D. rossmaniae, D. rudis, and D. vaccinii (syn.…”

“…Concerns about the damaging impacts of this pathogen on blueberry production led the European Food Safety Authority (EFSA) to recommend D. vaccinii as a quarantine pathogen for the European Union (Regulation (EU) 2016/2031 of 26 October 2016). Although D. vaccinii has been reported on blueberry plants in South America [17], North America [19,23], Europe [2,7,24] and Asia [18], the current knowledge about its pathogenicity on blueberries was barely explored. However, the most recent EU Regulation of 29 November 2919 (2019/2072), has no longer included D. vaccinii into the list of EU quarantine pests.…”