Xylella fastidiosa , phytopathogenic bacterium Bacterium Walwyn, - - PDF document

10/11/2018 1

Establishment of a Belgian Sentinel Plantation in Palma de Mallorca to Investigate the Susceptibility of Belgian Potential Host Plants to the Phytopathogenic Bacterium Xylella fastidiosa

Noemi Casarin1, Séverine Hasbroucq1,2, Amélie Emond 1, Júlia López Mercadal3,Maria Antonia Tugores3, Miguel Ángel Miranda Chueca3, Claude Bragard1, Jean-Claude Grégoire2

1Université catholique de Louvain (UCL ELI), Belgium 2Université libre de Bruxelles (ULB), Belgium 3University of the Balearic Islands (UIB), Spain

9-12 October 2018, Sursee (Switzerland) COST Global Warning Final Action Meeting

Xylella fastidiosa, phytopathogenic bacterium

DISEASE

Bacterium Insect vectors Host plants Environment

• Cicadellidae
• Cercopidae
• Aphrophoridae

> 350 (EFSA, 2015)

Kitajima, 2007 ColinHuttonPhoto, 2013 Gould, 2005 Walwyn, 2014

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Minerva, 2017 d-maps

Present Isolated cases

• X. fastidiosa, quarantine organism colonizing Europe since 2013

Jaén, 2017

• Objective : Studying the susceptibility of Belgian potential host plants by

exposing them to X. fastidiosa in a naturally contaminated area.

Sentinel plantation, a tool of studying the potential pathosystems

• Area chosen : Palma de Mallorca
• Xf detected since 2016.
• Presence of 2 subspecies : Xf subsp.

fastidiosa and Xf subsp. multiplex.

• Collaboration with the University of the

Balearic Islands.

Educol.net, 2017

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Preliminary tests and transport

• 81 Belgian plants selected
• 27 Prunus domestica cv. Opal
• 27 Salix alba
• 27 Quercus petraea

Prunus domestica Quercus petraea

• Brought from Belgium with phytosanitary passports
• Complementary tests: classical PCR Minsavage et al. (1994)

Salix alba

Choice of the plot

• Easy to connect to an irrigation system
• Presence of Philaenus spumarius and Neophilaenus spp. larvae
• Presence of some symptomatic host plants

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Sentinel plantation establishment

Sentinel plantation establishment

• Random distribution but reflecting potential gradients

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Sentinel plantation monitoring area

• Monitoring of the circulation of the

bacterium

• 100m-area around the plot divided

in 25 blocks

• Floristic inventory
• Plantation of « Spy plants » Rosmarinus
• fficinalis
• Insect vector sampling

+/- 170 inventoried plants

Floristic inventory around the plantation

Experimental plot Inventoried plants

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Floristic inventory around the plantation

+/- 170 inventoried plants

• 134 carob trees (78%)
• 31 wild olive trees (18%)
• 5 almond trees (3%)
• 2 pine trees (1%)

Experimental plot

Floristic inventory around the plantation

+/- 170 inventoried plants

• 134 carob trees (78%)
• 31 wild olive trees (18%)
• 5 almond trees (3%)
• 2 pin trees (1%)

36 hosts of Xf (21%) : wild

• live trees and almond trees

Experimental plot Non-host plants Host plants

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+/- 170 inventoried plants

• 36 hosts of Xf (21%) : wild
• lives and almond trees
• 23 symptomatic (64%)

Floristic inventory around the plantation

Experimental plot Asymptomatic Symptomatic Symptomatic host plants

Plantation of « Spy plants » Rosmarinus officinalis

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• Larvae inventory  frame 50 cm²
• Randomly thrown 4x/block
• Adults inventory  sweeping net
• 20 sweepings/block
• Some insects collected each month

for molecular analyses

Insect vector sampling methodology

• Philaenus spumarius abundance

Wim Veraghtert

Insect vector sampling results

5 10 15 20 25 30 35 40 45

March May June July September

Insect number Herbaceous layer Tree layer

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• Neophilaenus campestris abundance

British bugs

Insect vector sampling results

10 20 30 40 50 60 70 80 90 100

March May June July September

Insect number Herbaceous layer Tree layer

• Insects processed by molecular analyses for Xf detection ~ 100 insects
• Nested PCR with Minsavage et al. (1994) primers
• No positive detection…

Wim Veraghtert

Insect vector sampling results

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• 32 Rosmarinus in the monitoring area
• 2/3 symptomatic
• Some are drying
• 6 dead plants
• Detection with classical PCR

(Minsavage et al., 1994) No Xf detection…

Spy plants Rosmarinus officinalis results

Lachnaiasexpunctata Lachnaiaseptempunctata Quercus : under a net until mid-July

Sentinel plantation observations and results

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• Sampling of the 81 plants
• About 10 leaves per plant (the most symptomatic)
• DNA extraction with a CTAB-based protocol (Laboratory of Zoology, UIB)
• Xf detection by classical PCR (Minsavage et al., 1994)

Sentinel plantation observations and results

Salix alba Prunus domestica Quercus petraea

• No Xf detection in May, June, July and September…
• No detection in the « Spy plants » Rosmarinus officinalis.

Rosmarinus degraded, some dead Presence of symptomatic host plants

• No detection in the insect vectors collected.

Detection threshold Sampling not representative (tree layer)

• No detection of Xf in the Sentinel plants

Detection threshold Time to develop No herbaceous layer in the plot this year…

Conclusion

Wim Veraghtert

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• From 22 to 27 October  Last sampling for the 2018-season
• Continuation of the project in 2019 et 2020…

Project continuation

Thank you for your attention

Noemi Casarin1, Séverine Hasbroucq1,2, Amélie Emond 1, Júlia López Mercadal3,Maria Antonia Tugores3, Miguel Ángel Miranda Chueca3, Claude Bragard1, Jean-Claude Grégoire2

1Université catholique de Louvain (UCL ELI), Belgium 2Université libre de Bruxelles (ULB), Belgium 3University of the Balearic Islands (UIB), Spain

Establishment of a Belgian Sentinel Plantation in Palma de Mallorca to Investigate the Susceptibility of Belgian Potential Host Plants to the Phytopathogenic Bacterium Xylella fastidiosa