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Thuillier, J.-M.

Publications and source records attributed to Thuillier, J.-M..

2 recordsLinked to original sources

Insect-habitat-plant interaction networks provide guidelines to mitigate the risk of transmission of Xylella fastidiosa to grapevine in Southern France

O_LIXylella fastidiosa (Xf) is a xylem-limited bacterium that has been recorded in several European countries since its detection in 2013 in Apulia (Italy). Given the prominence of the wine industry in many southern European countries, a big threat is the development of Pierces disease in grapevines. Yet, the insect-habitat and insect-plant interaction networks in which xylem feeders, possible vectors of Xf, are involved around European vineyards are largely unknown. C_LIO_LIHere we describe these networks in three important wine-growing regions of southern France (Provence-Alpes-Cote dAzur, Occitanie, Nouvelle-Aquitaine) to identify the main source habitats of xylem feeders, and to gather information about their specialization degree at the habitat, plant family, and plant species levels. A total of 92 landscapes (and 700 sites) were studied over three sampling sessions in the fall 2020, the spring 2021, and the fall 2021. C_LIO_LIAmong the habitats sampled, meadows hosted the largest xylem feeder communities, followed by alfalfa fields. Vineyard headlands and inter-rows hosted slightly smaller xylem feeder communities, indicating that potential Xf vectors were thriving in the close vicinity of vulnerable plants. Finally woody habitats in general and grapevines in particular hosted very few xylem feeders, showing that transfer on vulnerable plants are rare, but not inexistent. In terms of specialization degrees, Philaenus spumarius, Aphrophora alni, Lepyronia coleoptrata, and Cicadella viridis were all similarly generalists at the habitat, plant family or plant species level. The only specialist was Aphrophora grp. salicina, which was restricted to riparian forests, and more specifically to Salicaceae. Neophilaenus spp. were extremely specialist at the plant family level (Poaceae), but rather generalist at the habitat and plant species levels. All 1017 insects screened for the presence of Xf tested negative, showing that Xf is not widespread in the studied regions. C_LIO_LIOur study provides new basic ecological information on potential vectors of Xf, especially on their specialization and feeding preferences, as well as practical information that may be relevant for the design of epidemiological surveillance plans. C_LI

ecology↗

Using insects to detect, monitor and predict the distribution of Xylella fastidiosa: a case study in Corsica

We sampled ca 2500 specimens of Philaenus spumarius throughout Corsica without a priori on the presence of symptoms on plants. We screened 448 specimens for the presence of Xylella fastidiosa (Xf) using qPCR and a custom nested PCR. qPCR appeared versatile and under-estimated the prevalence of Xf. Nested PCR showed that Xf was present in all populations. Molecular results were validated by prediction on the distribution of Xf made from tests conducted on plants, which shows the pertinence of using vectors in risk assessment studies. Xf was detected in tenerals and adults. Thus, P. spumarius could acquire Xf from its host plant, mostly Cistus monspeliensis in Corsica, which may act as reservoir for the next season. This contrasts with other observations and suggests that management strategies may have to be adapted on a case-by-case basis. At least two genetic entities and several variants of Xf not yet identified on plants were present in the insects, which suggests ancient introductions of Xf and a probable underestimation of the current diversity of the strains present in Corsica. Interestingly 6% of the specimens carried two subspecies. Studies are wanted to better characterize the strains present in Corsica and know how the disease was introduced, spread and why no sign of a potential epidemic was detected earlier. This study shows that, when sensitive enough methods are implemented, insects can be used to predict and better assess the exact distribution of Xf. Insects are indeed easy to collect, Xf multiply only in their foregut and does not become circulative, which facilitates its detection.\n\nKey messageO_LIInsect vectors can be used to detect, monitor and predict the distribution of Xylella fastidiosa\nC_LIO_LIThe widely used qPCR approach is not sensitive enough to detect low bacterial load\nC_LIO_LIDifferent strains/subspecies of Xf are widely distributed in Corsica which suggests old introduction(s)\nC_LIO_LIStrategies to manage Xf may need to be set up on a case-by-case basis\nC_LIO_LIThere is an urgent need to take stock of the situation in Europe to avoid unnecessary economic pressure on certain geographical areas and agricultural sectors.\nC_LI

ecology↗