Cutler, J (2021) DISCOVERY AND DEVELOPMENT OF NOVEL PARASITIC NEMATODES TO CONTROL SLUGS IN AGRICULTURE. Doctoral thesis, Liverpool John Moores University.

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Abstract

Terrestrial gastropods are highly pestiferous and pose a significant global threat to sustainable agriculture, horticulture and floriculture. Current control methods rely on metaldehyde formulated bait pellets. However, metaldehyde can harm non target organisms and cause environmental pollution. Metaldehyde is also due to be banned for use in the UK by 2022. A viable alternative is the gastropod parasitic nematode Phasmarhabditis hermaphrodita, which has been formulated into a biological control agent (Nemaslug®) by BASF Agricultural Specialities. However, the same strain of P. hermaphrodita (DMG0001) has been produced in an artificial environment for over 25 years and research suggests this strain is losing beneficial traits (e.g. virulence and host finding) and failing to provide protection against slug damage. The primary aim of this thesis was to use a collection of wild isolated Phas marhabditis species (P. hermaphrodita, P. neopapillosa and P. californica) to investigate whether they are more virulent than the commercial strain of P. hermaphrodita (DMG0001) to the pestiferous slug Deroceras invadens and the snail Cornu aspersum in laboratory experiments. Host feeding inhibition, numbers of nematode dauers produced on gastropod cadavers and natural variation in chemotaxis behaviour were also investigated. Additionally, the impact of virulent strains on beneficial non- target organisms and the mechanism of host behavioural manipulation were explored. Multiple wild strains were found to perform better than the commercial strain in regards to virulence, feeding inhibition, proliferation on cadavers and locating host cues. This research has demonstrated that other members of the Phasmarhabditis genus can be utilised as safe and effective biological control agents. This thesis presents which Phasmarhabditis species show the most potential for pathogenic ability and host seeking.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Nematology
Subjects:	Q Science > QH Natural history Q Science > QH Natural history > QH301 Biology Q Science > QK Botany Q Science > QL Zoology S Agriculture > S Agriculture (General)
Divisions:	Biological & Environmental Sciences (from Sep 19)
Date Deposited:	27 Sep 2021 10:27
Last Modified:	21 Nov 2022 12:22
DOI or ID number:	10.24377/LJMU.t.00015523
Supervisors:	Rae, R, Wilding, C and Swaney, W
URI:	https://researchonline.ljmu.ac.uk/id/eprint/15523

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