Impacts of climate change on the resilience of natural enemy communities for biocontrol of insect pests

There are significant challenges to finding new solutions for sustainable agriculture, whilst ensuring agricultural productivity on a global scale. Conservation biological control uses functionally diverse populations of natural enemies (predators, parasitoids, microbes) within agricultural systems to alleviate pest pressure and promote regulating ecosystem services, in the absence of pesticides.

Whilst we understand the role of parasitoids/predators and insect pathogens for biological control, and are beginning to acknowledge the importance of beneficial soil bacteria for plant health, less is known about the intricate interactions between these groups of organisms for controlling pests, especially under environmental change.

This project will investigate a novel approach of integrating above- and below- ground pest control simultaneously. The student will use a barley-aphid system to investigate the effects of climate change (elevated CO2) on multi-trophic interactions and the potential for increased pest pressures under future conditions. Exploring the impact of environmental changes in CO2 on multi-trophic interactions will bring innovative understanding of how microbial natural enemies may be affected under future environmental scenarios.

This has rarely been studied and especially not in the context of a community assemblage of multiple natural enemies where the value of this regulating ecosystem service will be assessed in terms of plant health and crop yield.

The PhD will build complexity, from lab-studies, to larger mesocosm greenhouse experiments and transferring to the field. There is also an exciting opportunity to engage with farmers to co-design key questions to address in the PhD and to disseminate outcomes from the studies. Objectives The overarching objectives are to:

1. Determine trade-offs between pest control services provided by soil bacteria and by fungi/parasitoids aboveground. 2. Determine the impact of environmental changes (eCO2) on biocontrol/disease transmission, and plant health. 3. Transfer knowledge from laboratory experiment to the field. 4. Engage end-user farmer groups with research input and outputs