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

Lead Research Organisation: University of Warwick
Department Name: School of Life Sciences


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


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Description During this project I have developed a novel approach to spraying known volumes of chemical or suspensions of pathogens onto target plants.
The project is using a type of analysis which has never been used in pathology. This technique is from a different field of research (ecotoxicology) and may provide a new and in-depth way to test the potential of combinations of insect control agents in an integrated pest management program. Currently, this approach has been used to design experiments, conduct bioassays and analyse the results. Further experiments need to be conducted to improve the method. These will be completed before the end of the project.
The different entomopathogenic fungi used in this project have different temperature profiles. This may cause them to react differently to the environmental conditions occurring in a crop growers greenhouse. Further questions which could be investigated would answer how we can predict which fungal pathogens are most successful for pest control if you know the conditions that they will be exposed to. Could the outcomes of large scale pest management be predicted based on small scale laboratory based experiments?
Significant differences were found in the pathogenicity of 18 different entompathogenic fungi when applied to aubergine plants infested with greenhouse whitefly.
Significant negative results were collected by combining entomopathogneic fungi with fungicides often applied to crops. Some of these fungicides had little to no effect on the growth and germination of the fungus. When the fungicide was applied to aubergine plants infested with whitefly, a significant proportion of the whitefly were killed.
This project has proven a successful collaboration between University, not for profit research centres and industrial partners.
Exploitation Route The outcomes of this project will improve our ecological knowledge on the interactions occurring between insect pathogens, chemical insecticides and the environment. By having an in-depth knowledge on these interactions, we can better design pest management practices used by greenhouse crop growers and allow the use of more sustainable, less harmful alternatives to chemical pesticides.

Outcomes of this project are useful for chemical and biological pest control companies. Having a better ecological understanding of what is occurring when mixtures are applied to crops will improve recommendations made by the companies that produce and sell these products. The novel experimental design used in this project could be useful to commercial partners to trial new mixtures of control agents for potential improved pest management.
Sectors Agriculture, Food and Drink,Chemicals,Environment,Manufacturing, including Industrial Biotechology

Description The outcomes of the project have been shared with the industrial partners. I have presented and discussed my work with the research and development team working for the chemical company BASF. I have also increased the reach of this type of research by sharing my experiences on my personal blog. I have an active twitter account to share my results and findings with international researchers. I am an active STEM ambassador, regularly attending events in Oxfordshire. I have been involved in a speed networking event at Didcot Aureus school. I also discussed my project for a whole day with high school students at the Warriner school. I am involved in the online program 'i'm a scientist, get me out of here!' where I can communicate with schools across the country as they ask questions about my research. By doing public engagement activities like these, I aim to normalise a career in science. Hopefully I will inspire future scientists.
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Education
Impact Types Cultural,Societal

Description Public Engagement funding
Amount £2,500 (GBP)
Organisation UK Centre for Ecology & Hydrology 
Sector Public
Country United Kingdom
Start 03/2018 
End 03/2019
Description Brownies visit to CEH 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Young girls in the local brownies group came to UKCEH to talk about the effect of plastics in the environment. Along with 2 other students, I helped show the girls how to use a microscope and the importance of reducing plastic usage. All attendees were enthusiastic and excited to ask questions.
Year(s) Of Engagement Activity 2018
Description I'm a scientist, get me out of here 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact I'm a scientist, get me out of here is an online interaction website where scientists can communicate with schools across the UK. I have a profile and schools send questions during active sessions so that I can answer and discuss further. Evening sessions also occur so that parents can get involved and ask questions. Each scientist competes to answer in the most interesting way. Students vote for their favourite scientist and the winner is given funding for further public engagement.
Year(s) Of Engagement Activity 2020
Description Personal blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I use my personal blog to describe my experiences as a PhD student. For example, significant training courses I have attended or what happened at my first international conference. I have been contacted through the blog by other PhD students asking for advice and further information.
Year(s) Of Engagement Activity 2017
Description STEM Speed Networking 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact I attended a STEM event at Didcot Aureus school. Groups of five 11 year olds would move from table to table with one STEM ambassador at each. I had five minutes to explain my project and answer questions before the next group of school children arrived. I did this for 2 hours and answered lots of informed questions.
Year(s) Of Engagement Activity 2018
Description School visit (Oxfordshire) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact I taught five 1 hour lessons about my research and its importance. Each class held 20-30 15 year olds. My feedback forms showed that they found the science interesting and they would consider a career in science.
Year(s) Of Engagement Activity 2019