Investigating the use of endophytic entomopathogenic fungi in crop protection

Research output: ThesisDoctoral Thesis

16 Downloads (Pure)

Abstract

Insect herbivores cause considerable damage to crops and there is an urgent need for effective pest management with reduced use of toxic chemicals. Entomopathogenic fungi, such as Beauveria bassiana, can protect glasshouse crops from insect pests but are currently ineffective when used in field crops due to exposure to the elements. These fungi can grow endophytically and here their potential role in protection of an important crop, oilseed rape, Brassica napus, is investigated. A method of inoculation by alginate seed coating was developed to consistently treat seeds before sowing. Inoculation led to consistently high levels of endophytic colonisation, determined by culturing, when plants were grown in sterile conditions. However, colonisation levels were much lower and more variable when plants were grown in non-sterile soil. Under both conditions, inoculation had no detrimental effect on plant growth. Inoculation with B. bassiana was found to impact plant metabolite profiles, regardless of endophytic colonisation and putative annotation suggested an increase in indole related pathways related to growth regulation and defence response. The microbiome of B. napus varied between leaf and root tissue but was unaffected by inoculation when plants were grown in non-sterile soil. A series of laboratory experiments found no effect on the survival and/or reproduction of specialist phloem feeding aphids, Brevicoryne brassicae, nor leaf chewing caterpillars, Pieris brassicae and Plutella xylostella. Additionally, no effects were reported on generalists of the two guilds, Myzus persicae and Mamestra brassicae. When potted plants were grown under semi-field conditions for the entire growing season inoculation had no impact on plant growth, yield or the insect communities associated with plants. Two field trials were set up however one failed to establishment and the other had poor establishment followed by significant slug and pigeon damage. Existing communities of entomopathogenic fungi in field soils were detected by baiting; spiking samples with B. bassiana suggested the inoculum could not compete in the soil. While the general technique has potential, significant improvements on inoculation methods and strain selection would be needed for it to become a feasible method of crop protection. 
Original languageEnglish
QualificationPh.D.
Awarding Institution
  • Royal Holloway, University of London
Supervisors/Advisors
  • Gange, Alan, Supervisor
  • Sarasan, Viswambharan, Supervisor, External person
  • Luke, Belinda, Supervisor, External person
  • Koricheva, Julia, Advisor
Thesis sponsors
Award date1 Jun 2022
Publication statusUnpublished - 2022

Keywords

  • Royal Holloway
  • Tara O'Neill
  • entomopathogen
  • endophyte
  • Beauveria
  • oilseed rape
  • Brassica napus
  • bassiana
  • fungi
  • biological control
  • crop protection
  • agro-ecology
  • bio control
  • biopesticide
  • applied ecology
  • alginate
  • Myzus persicae
  • Brevicoryne brassicae
  • Plutella xylostella
  • Mamestra brassicae
  • Pieris brassicae
  • inoculate
  • seed coating

Cite this