00:00In this video, we'll explore a case study of a potential application of tropolink,
00:07unravelling dissemination trajectories of an insect vector of plant pathogens.
00:13In the context of plant health, vector-borne pathogens cause tremendous crop losses each year,
00:19underscoring the importance of better understanding epidemic processes.
00:25In this case study, we'll use tropolink to try to identify the likely dissemination trajectories and patterns of an insect vector of plant pathogens.
00:35Here, Cacopsilla prunii, a jumping plant lice transmitting Candidatus phytoplasma prunorum,
00:42a phytoplasm causing the European stone fruit yellows,
00:45a disease affecting wild and cultivated prunus trees like apricot and plum trees.
00:51Let's take Montpellier's site for example.
00:54Leveraging our knowledge of the population dynamic and life cycle of the insect vector in this region,
01:00we'll compute backward air mass trajectories corresponding to possible arrival flights of the psyllidine orchard in spring using tropolink.
01:09Here, input parameters for tropolink include
01:13vector arrival dates and site, extracted from historical vector abundance data,
01:19flight duration and arrival hours, extracted from the literature and observation of the insects,
01:29and arrival altitude, determined through study of the height of the planetary boundary layer at the arrival site,
01:36a parameter available in tropolink trajectory output.
01:41Then, once the study has finished running, we extract the trajectory output from tropolink and import them in R.
01:49The software will perform all the following data analysis.
01:53This gives us all possible air masses used by psyllids when harving in Montpellier each spring.
01:59Then, we filter these trajectories using meteorological data available in the trajectory outputs given by tropolink,
02:08to keep only the trajectories wherein psyllids could realistically fly and survive.
02:13Thus, we obtain the air mass trajectories corresponding to all possible arrival flights of the psyllids
02:20the closest to their biology and atmospheric physics as possible.
02:24From these filtered trajectories, we can then compute the connectivities between the arrival site of the insect
02:31and each cell of a grid covering France, using the code for connectivity computation in R available in tropolink wiki.
02:41Thus, creating a heatmap of potential origin of the psyllid before the arrival flight in spring,
02:47where they can infect fruit trees.
02:51Then, comparing this heatmap with distribution of the psyllid overwintering host plant,
02:57we can determine precise potential source site of the psyllid,
03:01which we can then sample in a targeted way to confirm or not our hypothesis via population genetics,
03:08and, in finae, identify the true sources of the vectors before the arrival in our orchards.
03:14The main prospect for this work is to inform the development of new surveillance and prophylactic strategies,
03:24aligning with the global imperative to reduce pesticides use in plant health.
03:29Also, see you in touch with the plastic cartels.
03:30See you in the middle.
03:31The other thing, thanks for watching!
03:35By watching and watching and watching, watching and watching and watching and watching and watching!
