Keeping plant pests out by profiling geographical areas at risk

When new plant pests like insects, fungi, bacteria and viruses arrive in Europe they threaten our local plants and our biodiversity. Climate suitability analysis is a tool to assess the likelihood of this happening to help decision-makers keep them out. How does it work?

Global distribution of pests

We collect data on the global geographical distribution of specific pests and their biology, including the effects of climatic actors such as temperature, humidity and precipitation.

Data analysis

We analyse the data collected using mathematical models and climate indicators. These help to assess whether there are areas with climates suitable for the development of plant pests.

Risk assessment

The analysis is used to assess the likelihood of pests establishing and thriving in particular areas, taking into account both climatic suitability and the presence of host plants. The results help to determine where the pest could have an impact and where pest management efforts should be focused.

As part of its work on plant health, EFSA carries out pest categorisation and risk assessment, evaluates climate and habitat suitability, develops surveillance tools, and performs other technical tasks to support the European Commission, the European Parliament, and EU Member States.

EFSA’s plant health experts have reviewed a study that suggests the pathogen which causes citrus black spot disease (CBS) is present in Europe. Phyllosticta citricarpa is listed as a quarantine plant pest in the EU and has never before been identified in the territory.

The authors of the paper reported finding the fungal pathogen in domestic gardens in Portugal, Malta and Italy but said there was no evidence of the disease at any of the sites.

Although the authors applied advanced molecular techniques for identifying fungal species, EFSA’s Panel on Plant Health noted a number of limitations in the surveillance part of the study:

• It is not clear from the methodology presented how the sample locations and sites were chosen or how samples were collected.
• The sampling procedure was inconsistent and not statistically based.
• No explanation is given for how the CBS disease surveys were conducted. Without properly constituted disease surveys, there is little support for the conclusion that P. citricarpa did not lead to disease.

Surveys conducted by national plant protection organisations following publication of the paper have not confirmed its findings. Sampling will continue in the following seasons.

• Evaluation of a paper by Guarnaccia et al. (2017) on the first report of Phyllosticta citricarpa in Europe