Imperial College London


Faculty of Natural SciencesCentre for Environmental Policy

Research Fellow



+44 (0)1557 331 337a.w.leach




Silwood ParkSilwood Park






Much of my research has focused on the development and use of decision support tools (simulation and cost benefit assessment models) for managing pests and diseases in agriculture: cotton in Egypt; cocoa in Costa Rica (Leach, Krauss and Mumford, 2001) and Indonesia; coffee in India, Mexico and Colombia; vegetables in Malaysia and Tanzania; protein marketing in Bangladesh; citrus fruit in the Mediterranean basin (Cleanfruit  - EC Framework 6 project). 


Birds affected by Desert Locust controls in West Africa (copyright WC Mullié, 2009)

Part of the Cleanfruit project was spent developing a tool, the Pesticide Environmental Accounting (PEA) software (Leach and Mumford, 2008), to monetize the undesirable effects of pesticide applications in fruit orchards used against fruit flies.  Putting € signs to human health and environmental impacts makes it possible to perform cost benefit analysis of replacing pesticides with alternative technologies (Sterile Insect Technique) and gives decision makers a more tangible basis for policy development.  The PEA has been subsequently developed to apportion human health and environmental impacts to individual pesticides in (€/hectare) to Desert Locust controls in West Africa (Leach, Mullié, Mumford and Waibel, 2009).


Desert locust pesticide drums and storage (copyright WC Mullié, 2009)

Recently, I was part of a PRONE (an EC Framework 6 funded) project’s team to examine the potential role of insurance mechanisms to improve sustainability of fish stock exploitation by modifying behaviour to reduce risks (Mumford, Leach, Levontin and Kell, 2009).   

Insurance smoothing fishing revenues (Mumford et al, 2009)


Insurance smoothing fishing revenues (Mumford et al., 2009)

The Centre for Environmental Policy, Imperial College London focuses on, among other things, environmental risk and how it affects decision making and policy.  As part of the NNRAP project John Mumford and I developed a stochastic model to assess the moneterized impacts of non-native species introductions to the UK.  The Invasive Risk Impact Simulator (IRIS) has the facility to include the assessor's confidence in the data being entered.  Different degrees of confidence / uncertainty affect the decisions that policy makers take so capturing this could improve the robustness of policy decisions that emerge.   We are currently working on PRATIQUE, an EC Framework 7 project to enhance pest risk analysis methods.

IRIS software


Screenshot of IRIS software (Mumford and Leach, unpublished)

Future work includes a project with the UNICEF / UNDP / World Bank / WHO Special Programme for Research and Training in Tropical Diseases to develop objective guidance with countries considering the potential implementation of genetically modified mosquitoes for control of malaria and dengue.



Quinlan MM, Leach A, Jeger M, et al., 2020, Pest risk management in trade: The opportunity from using integrated combined measures in a systems approach (ispm 14), Outlooks on Pest Management, Vol:31, ISSN:1743-1026, Pages:106-112

Holt J, Leach AW, 2019, Linguistic variables as fuzzy sets to model uncertainty in the combined efficacy of multiple phytosanitary measures in pest risk analysis, Ecological Modelling, Vol:406, ISSN:0304-3800, Pages:73-79

van der Gaag DJ, Holt J, Leach AW, et al., 2019, Model of the probability of pest transfer to a site suitable for establishment following their arrival on imported fruit, cut-flower or vegetable produce, Crop Protection, Vol:117, ISSN:0261-2194, Pages:135-146

Mumford JD, Leach AW, Benedict MQ, et al., 2018, Maintaining quality of candidate strains of transgenic mosquitoes for studies in containment facilities in disease endemic countries, Vector-borne and Zoonotic Diseases, Vol:18, ISSN:1530-3667, Pages:31-38

Rindorf A, Mumford J, Baranowski P, et al., 2017, Moving beyond the MSY concept to reflect multidimensional fisheries management objectives, Marine Policy, Vol:85, ISSN:0308-597X, Pages:33-41

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