Xylella fastidiosa , phytopathogenic bacterium Bacterium Walwyn, - PDF document

10/11/2018 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 Casarin 1 , Séverine Hasbroucq 1,2 , Amélie Emond 1 , Júlia López Mercadal 3 ,Maria Antonia Tugores 3 , Miguel Ángel Miranda Chueca 3 , Claude Bragard 1 , Jean-Claude Grégoire 2 1 Université catholique de Louvain (UCL ELI), Belgium 2 Université libre de Bruxelles (ULB), Belgium 3 University of the Balearic Islands (UIB), Spain 9-12 October 2018, Sursee (Switzerland) COST Global Warning Final Action Meeting Xylella fastidiosa , phytopathogenic bacterium Bacterium Walwyn, Kitajima, 2007 2014 Insect DISEASE Host plants vectors - Cicadellidae > 350 (EFSA, 2015) - Cercopidae - Aphrophoridae ColinHuttonPhoto, 2013 Environment Gould, 2005 1

10/11/2018 X. fastidiosa , quarantine organism colonizing Europe since 2013 Present Isolated cases Jaén, 2017 d-maps Minerva, 2017 Sentinel plantation, a tool of studying the potential pathosystems • Objective : Studying the susceptibility of Belgian potential host plants by exposing them to X. fastidiosa in a naturally contaminated area. • Area chosen : Palma de Mallorca Xf detected since 2016. o Presence of 2 subspecies : Xf subsp. o fastidiosa and Xf subsp. multiplex . Collaboration with the University of the o Balearic Islands. Educol.net, 2017 2

10/11/2018 Preliminary tests and transport • 81 Belgian plants selected o 27 Prunus domestica cv. Opal o 27 Salix alba o 27 Quercus petraea • Brought from Belgium with phytosanitary passports • Complementary tests: classical PCR Minsavage et al. (1994) Prunus domestica Quercus petraea 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 3

10/11/2018 Sentinel plantation establishment Sentinel plantation establishment • Random distribution but reflecting potential gradients 4

10/11/2018 Sentinel plantation monitoring area • Monitoring of the circulation of the bacterium • 100m-area around the plot divided in 25 blocks o Floristic inventory o Plantation of « Spy plants » Rosmarinus officinalis o Insect vector sampling Floristic inventory around the plantation +/- 170 inventoried plants Experimental plot Inventoried plants 5

10/11/2018 Floristic inventory around the plantation +/- 170 inventoried plants Experimental plot • 134 carob trees (78%) • 31 wild olive trees (18%) • 5 almond trees (3%) • 2 pine trees (1%) Floristic inventory around the plantation +/- 170 inventoried plants Experimental plot Non-host plants Host plants • 134 carob trees (78%) • 31 wild olive trees (18%) • 5 almond trees (3%) • 2 pin trees (1%) 36 hosts of Xf (21%) : wild olive trees and almond trees 6

10/11/2018 Floristic inventory around the plantation +/- 170 inventoried plants Experimental plot Asymptomatic Symptomatic Symptomatic host plants • 36 hosts of Xf (21%) : wild olives and almond trees • 23 symptomatic (64%) Plantation of « Spy plants » Rosmarinus officinalis 7

10/11/2018 Insect vector sampling methodology • Larvae inventory  frame 50 cm² o Randomly thrown 4x/block • Adults inventory  sweeping net o 20 sweepings/block • Some insects collected each month for molecular analyses Insect vector sampling results • Philaenus spumarius abundance 45 40 35 30 Insect number 25 20 15 10 5 0 March May June July September Herbaceous layer Tree layer Wim Veraghtert 8

10/11/2018 Insect vector sampling results • Neophilaenus campestris abundance 100 90 80 70 Insect number 60 50 40 30 20 10 0 March May June July September British bugs Herbaceous layer Tree layer Insect vector sampling results • Insects processed by molecular analyses for Xf detection ~ 100 insects • Nested PCR with Minsavage et al. (1994) primers • No positive detection… Wim Veraghtert 9

10/11/2018 Spy plants Rosmarinus officinalis results • 32 Rosmarinus in the monitoring area o 2/3 symptomatic o Some are drying o 6 dead plants • Detection with classical PCR (Minsavage et al ., 1994) No Xf detection… Sentinel plantation observations and results Lachnaiasexpunctata Lachnaiaseptempunctata Quercus : under a net until mid-July 10

10/11/2018 Sentinel plantation observations and results • 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) Prunus domestica Salix alba Quercus petraea • No Xf detection in May, June, July and September… Conclusion • 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 Wim Veraghtert 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… 11

10/11/2018 Project continuation • From 22 to 27 October  Last sampling for the 2018-season • Continuation of the project in 2019 et 2020… Thank you for your attention 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 Casarin 1 , Séverine Hasbroucq 1,2 , Amélie Emond 1 , Júlia López Mercadal 3 ,Maria Antonia Tugores 3 , Miguel Ángel Miranda Chueca 3 , Claude Bragard 1 , Jean-Claude Grégoire 2 1 Université catholique de Louvain (UCL ELI), Belgium 2 Université libre de Bruxelles (ULB), Belgium 3 University of the Balearic Islands (UIB), Spain 12