Management of soil dwelling pests such as wheat bulb fly, cabbage root fly, carrot fly and wireworm, now rely on the use of insecticide seed treatments, as insecticides available as a soil drench application are now limited since the revocation of chlorpyrifos in 2016. The loss of the impending loss of other seed treatments used in cereals and carrots will limit further the available options for the management of soil-dwelling pests of several crops. Consequently, novel alternatives to the current management of soil-dwelling pests are required, that have a satisfactory environmental profile, are acceptable to growers, industry, processors, supermarkets and the public.
Entomopathogenic nematodes (EPN), entomopathogenic fungi (EPF) and entomopathogenic bacteria (EPB) are naturally present in soil, and current research at SRUC and the University of Edinburgh (Enhancing the soil food web to control soil dwelling pests of field vegetables – Teagasc Walsh Fellowship 2013-2020) – has demonstrated the importance of natural populations of EPN’s, EPF and EPB in reducing pest damage.
EPN are attracted to semiochemicals released by the roots of plants and associated with their insect hosts (Dillman et al., 2012). Some EPF produce motile zoospores, and some EPB have flagella that facilitate movement through the soil. EPF and EPB attraction to potential insect hosts has not been studied in detail, particularly in a pest management context.
Previous research at SRUC has identified semiochemicals released by wheat roots that affect the behaviour of newly-hatched wheat bulb fly larvae (Rogers & Evans, 2013; Rogers et al., 2013), and at least one of these, carbon dioxide, is also an attractant for entomopathogenic nematodes (EPN’s).
This project aims to characterise the behaviour of specific EPN, EPF and EPB in response to host-insect and plant derived semiochemicals, with the aim of improving entomopathogen efficacy for the management of soil pests by attracting and aggregating them to the root zone of crop plants (where the pests are themselves attracted and aggregate) using semiochemical seed treatments.
Candidate EPN/EPF/EPB attractant and/or aggregant compounds will be identified from the scientific literature and their attractant/aggregant properties confirmed by behavioural bioassays developed in previous SRUC work on invertebrate attraction (Rogers & Evans, 2013; Rogers et al., 2013), and techniques for measuring the movement of microorganisms developed by The Edinburgh Complex Fluids Partnership (www.edinburghcomplexfluids.com) based at the University of Edinburgh.
Attractant/aggregant semiochemicals will be formulated as a seed treatment for application to wheat, carrot and broccoli seed to evaluate whether they increase the prevalence of entomopathogens in the root zone when sown into different soil types. Bioassays in the laboratory, glasshouse and ultimately in replicated field trials will evaluate the impact of semiochemical seed treatments on crop plants such as wheat and carrots and broccoli in terms of any phytotoxicity, entomopathogen prevalence in the root zone and pest damage.
The overall aim of this project will be to determine whether natural control of pests by entomopathogens can be enhanced, with a view to developing novel approaches for the management of soil-dwelling pests.
The student will have access to skills training offered by both SRUC and the University of Edinburgh through participation in formally taught courses, or developed during the course of their research. Skills include:
• Research Environment
• Research Management
• Personal Effectiveness
• Communication Skills
• Networking and Team working
• Career Management
In addition other courses offered by SRUC, the University of Edinburgh (http://www.ed.ac.uk/institute-academic-development/postgraduate/doctoral/courses/course-list
) and Biomathematics and Statistics Scotland are available for the student to attend
Student attendance and participation in external courses, seminars, workshops and national and international conferences is encouraged and is considered an important part of doctoral training.
Applicants should download the required forms from http://www.eastscotbiodtp.ac.uk/how-apply-0
and send the following documents to [email protected]
a. EASTBIO Application Form
b. EASTBIO DTP Equality Form
d. Academic transcripts (a minimum of an upper second class or first class honours degree or equivalent is required for PhD study
e. Two references should be provided by the deadline using the EASTBIO reference form (http://www.eastscotbiodtp.ac.uk/how-apply-0
). Please advise your referees to return the reference form to [email protected]
f. If you are nominated by the supervisor(s) of the EASTBIO PhD project you wish to apply for, they will provide a Supervisor Support Statement.