Multiple stressor effects in biological pest control; improving efficacy in challenging environments

点击翻译按钮获取中文摘要

There is an urgent need to develop new innovations in agriculture that enable crops to be grown without harming the environment. At the moment, farmers are heavily reliant on synthetic chemical pesticides to protect crops against plant pests and diseases, but excessive use can be damaging to wildlife and the environment. Biopesticides are an "environmentally friendly" crop protection agent, based on natural products or living organisms. They are intended for use in Integrated Pest Management (IPM) systems, in which different crop protection tools are used together to reduce over reliance on chemical pesticides. Whilst the use of biopesticides is increasing rapidly, there remains a lack of basic knowledge about how they interact with other crop protection methods and how this affects levels of pest control. This PhD project concerns research to develop new knowledge on biopesticides based on insect pathogenic microorganisms. The main focus is to characterize and to better understand their interactions with chemicals and other biopesticides using an eco-toxicological modeling approach. This will include studies of how microbial biopesticides and pesticides interact under different environmental conditions in cropping systems (e.g. Hesketh & Hails, 2015). The overarching aims of this project are therefore; - to identify where, and how, pathogens can be combined with chemical pesticides/fungicides for maximum and reliable effects in terms of pest control. - to understand how impacts of additional stressors of varying climatic conditions/environments will mediate change in interactions between pathogens/chemicals and the implications this has for pest control. The project will have extensive experimental laboratory and field components as well as training in statistical analysis. The experimental work will primarily focus on the entomopathogenic fungus, Beauveria bassiana (the basis of several biocontrol products) and host insects such as aphids and whitefly in tomatoes as an exemplar crop. Experiments will progress from initial laboratory, controlled experiments in the first 1-2 years with small microcosms, with increasingly complex experiments in glasshouses in years 3-4. These experiments will be designed to improve understanding and detect positive (additive and synergistic) and negative (antagonistic) ecological interactions between microbial pathogens/chemicals in combination. The ability to describe how microbial insect pathogens interact will be furthered by using novel experimental designs and data analysis based on the MIXtox models (Jonker et al., 1995). This will improve current methods of statistical analysis of the effects of mixtures of pathogens/toxicants