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International audience; Potential spread of the pine wood nematode (PWN), Bursaphelenchus xylophilus, is driven by both insect vector and human-mediated dispersal. At local scale, dispersal capacity of the vector may explain the failure of eradication measures such as host tree removal. In Europe, the PWN is transported by the pine sawyer beetle, Monochamus galloprovincialis. Although the insect is known to disperse at short distances following mark-release-recapture experiments, the insect is able to fly rather long distances on a flight mill (cumulated distance of 16 km on average and up to 63 km). A first dispersal model was developed to describe the flight trajectory of M. galloprovincialis in non-fragmented pine forests. The shape of the dispersal kernel was fitted to the data recorded in the flight mill experiment to capture the proportion of long-distance flights compared to short-distance flights. Then, the dispersal model was refined to flight distances recorded in the field using data from the mark-recapture experiments conducted in a pine forest. Here, we will present how this model was adapted to simulate the dispersal of the insect vector in heterogeneous landscapes, e.g. a mosaic of pines, broadleaf trees, and open areas. This model was fitted to recent data from other mark-release-recapture experiments in such diverse landscapes.

International audience; Insect pests are one of the major threats to forests. Although invasive species cause more and more impacts, native species could also become real pests. The population dynamics of insects relies on several factors, going from weather to stand conditions. Due to global change, insects could face conditions they have never encountered, leading to unusual population outbreaks. Forest managers need to consider these possible emergent pests. However, the biology of these new pests is generally poorly described and predicting insect outbreaks is thus very challenging. In this context, we have developed a generic model of emergence to describe local outbreaks. This model describes the probability of occurrence of an outbreak at a given time and at a given area, based on several conditions (34 variables). It has been built and parametrized on different orders of European forest pests. This parametrization allows obtaining species profiles that can be used as a baseline to make predictions even if poor data are available on the pest, to ensure the genericity of the model. This is to our knowledge the very first generic outbreak model that has been developed so far. This model was coded in R and a user-friendly version using a shiny app was developed. In this work, we are going to present the model and its validation.

The world's forests have never been more threatened by invasions of exotic pests and pathogens, whose causes and impacts are reinforced by global change. However, forest entomologists and pathologists have, for too long, worked independently, used different concepts and proposed specific management methods without recognising parallels and synergies between their respective fields. Instead, we advocate increased collaboration between these two scientific communities to improve the long-term health of forests. Our arguments are that the pathways of entry of exotic pests and pathogens are often the same and that insects and fungi often coexist in the same affected trees. Innovative methods for preventing invasions, early detection and identification of non-native species, modelling of their impact and spread and prevention of damage by increasing the resistance of ecosystems can be shared for the management of both pests and diseases. We, therefore, make recommendations to foster this convergence, proposing in particular the development of interdisciplinary research programmes, the development of generic tools or methods for pest and pathogen management and capacity building for the education and training of students, managers, decision-makers and citizens concerned with forest health.

Background: The pine processionary moth (PPM) is an important insect defoliator of pine trees. This pest is commonly found in natural pine stands, plantations and ornamental trees in European cities. The urticating setae released by larvae cause severe health problems to humans and animals. With climate change, the PPM phenology is getting more and more variable. As a consequence, the number of urtication problems is increasing and the Bt spray is less effective. Here, we aim at presenting preliminary results and our perspectives on how climate change affects this insect’s phenology.Materials/Methods: Experiments will be done in incubators to assess thermal needs of several developmental stages (eggs and larvae). These data will feed a phenology model based on performance curves. Phenology data will be collected on the field to validate the model in different bioclimatic regions. The timing of adult emergences will be monitored using pheromone traps. To monitor processions, we will collect bags of procession traps every week to check the capture of processions, and we will install cameras in these traps to determine a posteriori the date of procession. Besides, to apply the phenology model, the influence of the silk nest on the actual temperatures experienced by larvae has to be taken into account. We will therefore model the deviation between air temperature and temperature in PPM nests.Results and discussion: Although this work started in autumn 2018, we will present preliminary results on field observation. We will present phenology data collected in the 1970s in different bioclimatic regions in France, data collected during the last years, and the changes observed in temperatures. Conclusion: A phenology model is a key milestone for the understanding of the PPM response to climate change, as it will enable providing decision-support to adequately time Bt sprays, as well as alerts for urtication risks.

Recently, the number of insect species that were accidentally introduced increased mainly due to international trade of ornamental plants which provide major pathways to insects. One example of this phenomenon is the box-tree moth, Cydalima perspectalis. This insect is an important threat for ornamental and natural box trees in Europe. It was observed for the first time in Germany in 2007 and then spread across Europe and Caucasus Region. The aim of this work is to study the role the box-tree moth phenology on its spread in France. In addition, we test different control methods to stop the fast expansion of the box-tree moth. We constructed a phenological model with 4 compartments corresponding to the 4 stages of the box-tree moth: eggs, larvae, pupae and adults. We used biological data from Nacambo et al. (2014) that gives the degree-days needed to go from a stage to the next. The third and fourth instar enter diapause and we therefore analyzed the effect of diapause on the generations’ number, phenology of each stage and adult flight curve.We compared our results with some data collected in the field near Orléans, in France, in 2014 and 2015. Our model predicts field observations: (i) with diapause, there are 2 generations, and (ii) adult abundance is maximal in June and August.We extended the model to include several control methods. The aim is to give a decision-making tool. There are 3 available methods of control: insecticide, pheromone traps and biological control. Based on our model, we tested the impact of the number and the date of control campaigns and the control intensity. Insecticides and biological control give good results but not pheromone traps. Further work will test also the effects of combining several control methods.

International audience; 1- Pheromone traps are widely used for monitoring or managing insect pest populations. However, it is important to know their range of attraction to optimize the setting of pheromone trap networks. 2- We propose an easy method based on the use of pairs of adjacent traps located at decreasing distance from each other. The range of attraction is deduced from the observation of reduced trap capture when the attraction range of two adjacent traps starts overlapping. The relationship between the relative trap capture and the distance between paired traps is fitted with a logistic curve. 3- To empirically test these predictions, we conducted trapping experiments with the beetle Monochamus galloprovincialis, the insect vector of the pine wood nematode. Fifteen pairs of traps separated by 25 to 300 m, in France, and 18 pairs of traps distant from 25 to 400 m, in Portugal, were installed in maritime pine plantation landscapes. 4- In both countries, the relative percentage of capture per trap per week was best fitted by a logistic model with two parameters. The estimated attraction ranges were 92 m (confidence interval = 62–211 m) in France and 123 m (confidence interval = 64–491 m) in Portugal. 5- The interference between paired traps thus provides a simple and robust method for estimating the attraction range of pheromone traps.