Conclusions and recommendations

Research required

Prominent research gaps related to climate change and pests are listed in Table 6. Funding bodies and organizations conducting research should consider these research gaps, where possible, for inclusion in their research programmes. In particular, in most geographical areas greater attention needs to be paid to sustaining comprehensive and multidisciplinary research programmes. Research programmes should cover the need of industrialized as well as developing countries. A long-term financial commitment will be required in order to capture the long-term effects of ongoing and future climate change and related pest risk, including testing methods to minimize risk. For this reason, a few “hot spots” (climate-sensitive production areas) should be selected for implementation of long-term research and development activities (“Climate Change Demonstration Sites for Pest Risk Analysis and testing Pest Risk Reduction Methods”, CCDS-PRA-PRRM).

Table 6. Examples of gaps in climate-change research related to plant pests

In addition, investment by national governments should be directed to strengthening national surveillance systems and structures, such as diagnostic laboratories, in order to be able to rapidly counteract possible biological invasions. Moreover, well-functioning PRA units should be put in place, in order to be able to prevent them.

Some specific issues requiring research are highlighted below.

Studies on the effect of climate change on plant-protection products and on management strategies

There are many research gaps that need to be filled in this field. It is possible, for example, that pests may become resistant to plant-protection products if the usage of such products becomes more frequent in response to increased pest prevalence due to climate change. However, research is needed to explore this. Furthermore, the direct effect of climate change on the effectiveness of the management strategies adopted, particularly on chemical or biological control measures, has not been studied enough up to now (Gilardi et al., 2017, Gullino et al., 2020) and should be much more extensively investigated (Table 6). Results from a few experiments are already available, for instance suggesting that global warming may increase the risk of herbicide-resistant weeds because of enhanced temperature-dependent detoxification of the herbicide by the weed (Matzrafi et al., 2016). Research is also needed on below-ground pests, as most research related to potential climate-change effects on pests has disproportionately focused on above- rather than below-ground pests, despite the importance of the latter pests on below-ground processes and their influence on soil health (Chakraborty, Pangga and Roper, 2012; Pritchard, 2011).

Studies on the effects of climate change on natural enemies

The impact of climate change on natural enemies and antagonists and the subsequent effect of this on pest control are not yet well understood (Eigenbrode, Davis and Crowder, 2015). In the case of grape pest insects, it has been suggested that future pest management should be based on a sound set of field data collected for both pests and antagonists under climate-change conditions (Reineke and Thiéry, 2016). A better understanding of the impact of climate change on ecological processes, including at community level, will allow general principles to be incorporated into management practices (Macfayden, McDonald and Hill, 2018).

Forestry and unmanaged ecosystems

Pests have been investigated much more in agriculture compared to forestry settings (Ormsby and Brenton-Rule, 2017), and research related to unmanaged ecosystems is rare (Harvell et al., 2002). This highlights the need for multidisciplinary collaboration, coordination and knowledge exchange in climate-change biology research to bring together scientists working on different biota within the same ecosystem, for instance plant pathologists and entomologists (Jactel et al., 2020), and those working on different ecosystems and sectors, such as agriculture, forestry and unmanaged ecosystems (e.g. the “Circular Health” or “One Health’’ approaches).