First Report of <i>Phytopythium vexans</i> Causing Decline Syndrome of <i>Actinidia deliciosa</i> ‘Hayward’ in Italy

Prencipe, Simona; Savian, Francesco; Nari, L.; Ermacora, P.; Spadaro, D.; Martini, Marta

doi:10.1094/pdis-10-19-2101-pdn

Cited by 22 publications

(33 citation statements)

References 6 publications

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“…KD spreads following an oil-spot pattern, with an astonishing speed that can compromise the whole orchard in only one or two growing seasons [2]. Currently, studies on KD are mostly focused on understanding the aetiology of the disease, which has not yet been fully clarified, but it seems that an interaction between waterlogging and several soil-borne pathogens is necessary to induce the disease [2,[10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Prediction of the Kiwifruit Decline Syndrome in Diseased Orchards by Remote Sensing

et al. 2020

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Eight years after the first record in Italy, Kiwifruit Decline (KD), a destructive disease causing root rot, has already affected more than 25% of the area under kiwifruit cultivation in Italy. Diseased plants are characterised by severe decay of the fine roots and sudden wilting of the canopy, which is only visible after the season’s first period of heat (July–August). The swiftness of symptom appearance prevents correct timing and positioning for sampling of the disease, and is therefore a barrier to aetiological studies. The aim of this study is to test the feasibility of thermal and multispectral imaging for the detection of KD using an unsupervised classifier. Thus, RGB, multispectral and thermal data from a kiwifruit orchard, with healthy and diseased plants, were acquired simultaneously during two consecutive growing seasons (2017–2018) using an Unmanned Aerial Vehicle (UAV) platform. Data reduction was applied to the clipped areas of the multispectral and thermal data from the 2017 survey. Reduced data were then classified with two unsupervised algorithms, a K-means and a hierarchical method. The plant vigour (canopy size and presence/absence of wilted leaves) and the health shifts exhibited by asymptomatic plants between 2017 and 2018 were evaluated from RGB data via expert assessment and used as the ground truth for cluster interpretation. Multispectral data showed a high correlation with plant vigour, while temperature data demonstrated a good potential use in predicting health shifts, especially in highly vigorous plants that were asymptomatic in 2017 and became symptomatic in 2018. The accuracy of plant vigour assessment was above 73% when using multispectral data, while clustering of the temperature data allowed the prediction of disease outbreak one year in advance, with an accuracy of 71%. Based on our results, the unsupervised clustering of remote sensing data could be a reliable tool for the identification of sampling areas, and can greatly improve aetiological studies of this new disease in kiwifruit.

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Section: Introductionmentioning

confidence: 99%

Prediction of the Kiwifruit Decline Syndrome in Diseased Orchards by Remote Sensing

et al. 2020

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“…Two species, belonging to Phytopythium genus, were isolated and emerged as potential pathogens: Phytopythium vexans and Phytopythium chamaehyphon. Pathogenicity of P. vexans on kiwifruit vine and its association to KVDS was previously demonstrated by Prencipe et al (2020), while the fulfillment of Koch's postulates for P. chamaehyphon was not determined and is the focus of the present work.…”

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confidence: 86%

“…Phytophthora genera) seem to play a major role in KVDS (Savian et al 2020a;Donati et al 2020;Prencipe et al 2020), however, also fungi (genus Desarmillaria) and bacteria (genus Clostridium) have been associated with the disease (Donati et al 2020;Spigaglia et al 2020).…”

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confidence: 99%

Pathogenicity of Phytopythium chamaehyphon: A New Player in Kiwifruit Vine Decline Syndrome of Actinidia chinensis var. deliciosa ‘Hayward’ in Italy

et al. 2021

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Kiwifruit Vine Decline Syndrome (KVDS) is a serious soil-borne disease that degrades the fine roots of both Actinidia chinensis var. deliciosa and var. chinensis. The disease seems to be the result of an interaction between several soil-borne pathogens, mostly oomycetes, and waterlogging. This work investigates the pathogenicity of the oomycete Phytopythium chamaehyphon recently isolated from roots of diseased plants. Pathogenicity was tested in 6-month-old and 1-year-old plants that after inoculation were flooded up to three times to induce symptom appearance. Leaf wilting and root rot typical of KVDS was observed in all the plants inoculated with P. chamaehyphon strain KD-15 (PCHA) and in all the positive controls potted in a mix of peat and soils collected in KVDS-affected orchards, while negative controls remained symptomless. Disease development on 6-months-old plants was characterized by unusual degradation of the not-lignified collar, occurring even in absence of flooding. Conversely, on 1-year-old plants, symptoms faithfully reproduced KVDS dynamics observed in orchard. This work confirmed the pathogenicity of P. chamaehyphon and raised new questions about the actual role of waterlogging in KVDS etiology.

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“…helicoides (root rot and the stems of many plants) and Pp. vexans (root rot of many plants including kiwi) (Javadi and Sharifnabi 2016;Afandi et al 2018;Prencipe et al 2020). In 2011, Yang et al (2013) described disease symptoms on begonia (Begonia × semperflorens-cultorum cv.…”

Section: Introductionmentioning

confidence: 99%

Phytopythium: origin, differences and meaning in modern plant pathology

Tkaczyk

2020

Folia Forestalia Polonica

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The genus Phytopythium is a relatively new group of organisms distinguished from the Pythium genus. These are organisms closely related to Pythium and Phytophthora, with similar structure and biology. Despite many similarities, this genus is characterised by several morphological features that allow it to be easily identified. Until now, more than 20 species belong to this genus, most of which are saprophytic organisms. However, there is also a group of species particularly dangerous to plants. These species include, among others, Pp. litorale, Pp. helicoides and Pp. vexans. The purpose of this work was to collect information about these organisms and present them in a condensed form. The study contains basic information about the history of the type of separation, differences in morphology distinctive genus of Phytopythium, Phytophthora and Pythium and information about diseases and host plants. Information is also provided on the potential threat posed by these organisms to forest ecosystems.

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First Report of Phytopythium vexans Causing Decline Syndrome of Actinidia deliciosa ‘Hayward’ in Italy

Cited by 22 publications

References 6 publications

Prediction of the Kiwifruit Decline Syndrome in Diseased Orchards by Remote Sensing

Prediction of the Kiwifruit Decline Syndrome in Diseased Orchards by Remote Sensing

Pathogenicity of Phytopythium chamaehyphon: A New Player in Kiwifruit Vine Decline Syndrome of Actinidia chinensis var. deliciosa ‘Hayward’ in Italy

Phytopythium: origin, differences and meaning in modern plant pathology

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