A phenological model of the invasive box-tree moth Cydalima perspectalis
Résumé
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.