Valérie Fournier's Lab

About the lab

We are an entomology lab. We work on agricultural and ecological questions on beneficial arthropods (pollinators, predatory mites, etc.) and pests. Our research topics include the potential of arthropods as biological control agent for crop protection, the biodiversity of wild bees and other pollinators in various crops and settings and the health of the honey bee related to various environmental stress.
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Featured research (11)

Climate change has facilitated the introduction, establishment, and movement of invasive species in northern regions, enabling the colonization of previously unsuitable areas. While the responses of insects to these changes have been increasingly studied, our understanding of how such alterations impact trophic interactions still requires further research to make reliable predictions about the spread of diseases in a warming world. Phytoplasmas, a group of obligate parasitic unculturable Mollicutes, primarily rely on leafhoppers (Hemiptera: Cicadellidae) for transmission, spread, and survival. Phytoplasmas are associated with over 600 diseases affecting more than 1,000 plant species, including berries, grapevines, and other small fruits. In North America, diseases such as grapevine yellows, blueberry stunt, and strawberry green petal diseases have been linked to phytoplasma strains transmitted by known leafhopper species. However, the number of phytoplasma diseases has significantly increased in North America over the past decade, suggesting the presence of unidentified vectors or an abundance of leafhopper vectors. This short review provides an overview of the current knowledge on leafhoppers as vectors of phytoplasmas to berries, focusing on the last decade's research in Canada. This paper also explores the potential implications of climate change on this pathosystem, including the anticipated range expansion of leafhopper species, changes in phytoplasma acquisition and transmission, and the risk of new leafhopper-transmitted plant-pathogen introductions through the arrival of new leafhopper species.
Climate change is reshaping agriculture and insect biodiversity worldwide. With rising temperatures, insect species with narrow thermal margins are expected to be pushed beyond their thermal limits, and losses related to herbivory and diseases transmitted by them will be experienced in new regions. Several previous studies have investigated this phenomenon in tropical and temperate regions, locally and globally; however, here, it is proposed that climate change’s impact on agriculture can be traced through the study of Nearctic migratory insects, specifically leafhoppers. To test this hypothesis, leafhoppers in strawberry fields located in the province of Québec, eastern Canada, were evaluated. The strawberry-leafhopper pathosystem offers a unique opportunity because leafhoppers can transmit, among other diseases, strawberry green petal disease (SbGP), which is associated with pathogenic phytoplasmas. Here, we found that in the last ten years, the number of leafhoppers has been increasing in correspondence with the number of SbGP cases detected in eastern Canada, reporting for the first time ten species new to eastern Canada and two to the country, although the leafhopper diversity has been seriously affected. Our model using more than 34 000 leafhoppers showed that their abundance is influenced by temperature, a factor that we found also influences the microbiome associated with Macrosteles quadrilineatus , which was one of the most abundant leafhoppers we observed. One of our most striking findings is that none of the insecticides used by strawberry growers can control leafhopper incidence, which could be linked to microbiome changes induced by changing temperatures. We suggest that Nearctic leafhoppers can be used as sentinels to trace the multilayered effects of climate change in agriculture. GRAPHICAL ABSTRACT IN BRIEF The current climate crisis is reshaping insect biodiversity and abundance, but little is known about the direct effect of this phenomenon on agriculture. In this study, we explored leafhoppers, a group of agriculturally important insect pests and disease vectors, as sentinels of the effect of climate change on agriculture. Our findings indicate that this group of insects can help us to understand the effect of the current climate crisis on insect invasions, diversity, abundance, disease dynamics and insecticide resistance and to take quick action to ensure food security while achieving more sustainable agriculture. HIGHLIGHTS Migratory leafhoppers benefit from temperature increases Leafhopper-transmitted diseases have increased in the last decade New non-migratory leafhoppers can be found now in Nearctic regions Leafhopper insecticide resistance could be linked to the insect microbiome
Le Québec est la principale province productrice de fraises au Canada. En 2018, la production de fraises était évaluée à un volume de plus de 15 millions de tonnes et représentait des revenus de 66 millions de dollars (Gouvernement du Québec, 2021). Malheureusement, dans les années à venir, les rendements de la culture pourraient être perturbés par les effets des changements climatiques. Parmi les nombreuses conséquences des changements climatiques, il pourrait y avoir une augmentation de la pression exercée sur les cultures de fraises par certains ravageurs ou agents pathogènes déjà présents au Québec, mais également une augmentation des introductions de nouveaux insectes ravageurs et de nouvelles maladies (Lehmann et al., 2020). Les changements climatiques ont une influence considérable sur ces insectes, car l’augmentation des températures favorise leur métabolisme et leur développement (Lehmann et al., 2020). Des températures plus élevées perturbent également les autres activités des insectes, comme l’alimentation, la reproduction, la croissance et les déplacements (Weintraub et al., 2019). Par conséquent, les hausses de température auront potentiellement pour effet d’accroître les densités de population d’insectes ravageurs dans les champs de fraises et augmenteront l’intensité des dommages ainsi que les pertes de rendements.
The foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), and the melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are among the serious insect pests found in greenhouses. The efficacy of microbial control against these insects has been demonstrated and can be enhanced by the combination of different microbial agents. This study evaluated the efficacy of Bacillus pumilus Meyer and Gottheil PTB180 and Bacillus subtilis (Ehrenberg) Cohn PTB185, used alone and together, to control these two aphids both in the laboratory and in greenhouse on tomato, Solanum lycopersicum Linnaeus (Solanaceae), and cucumber, Cucumis sativus Linnaeus (Cucurbitaceae), plants. The results from the laboratory tests showed an increase in mortality induced by all biological treatments. In the greenhouse, all treatments induced mortality rates significantly higher than that of the control for A. solani . Similarly, all treatments performed better than the control against A. gossypii , significantly reducing its reproduction. Furthermore, we found no additive effects when mixing products nor negative interactions affecting survival for the bacteria investigated. These microorganisms therefore have potential for use in biological control.

Lab head

Valérie Fournier
  • Department of Phytology
About Valérie Fournier
  • I am full professor at Laval University and my research focuses on agricultural entomology and ecology of insects and mites. I am interested in wild pollinators’ biodiversity, honeybee’s health, beneficial insects’ conservation, crop protection and biological control. My work is often linked with pesticides, either assessing their impacts or developing tools to reduce their use. I supervised more than 30 graduate students, led more than 20 projects and published in high impact journals.

Members (7)

Frédéric McCune
  • Laval University
Amélie Gervais
  • Laval University
Phanie Bonneau
  • Laval University
Sandrine Lemaire- Hamel
  • Laval University
Guillaume Blais
  • Laval University
Virginie Bernier
  • Laval University

Alumni (9)

Sabrina Rondeau
  • University of Ottawa
Olivier Samson-Robert
  • Laval University
Joseph Moisan-De Serres
  • Le ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec
Andrée Rousseau
  • Centre De Recherche En Sciences Animales de Deschambault, Québec, Canada