“Catch me if you can” – improving monitoring and control of vine weevil (Otiorhynchus sulcatus) in soft fruit and ornamental crops.

Fezza, E. (2024) “Catch me if you can” – improving monitoring and control of vine weevil (Otiorhynchus sulcatus) in soft fruit and ornamental crops. Doctoral thesis, Harper Adams University.

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Abstract

Vine weevil (Otiorhynchus sulcatus F.; Coleoptera: Curculionidae) is widely considered to be one of the most important soft-fruit and ornamental crop pests worldwide. Management options for vine weevil populations have historically relied on conventional synthetic insecticides. Much progress has been made in developing alternatives to conventional synthetic insecticides for vine weevil control. Research has focused on the use of entomopathogenic nematodes (EPNs) so that standard practice is now to use EPNs, such as Steinernema kraussei or Heterorhabditis bacteriophora, to control vine weevil larvae. However, despite progress in developing sustainable control methods, less progress has been made in developing the other components required to form a holistic integrated pest management (IPM) programme for this pest. The series of experiments presented in this thesis seek, through the development of an improved monitoring tool as well as the application of a biopesticide as an alternative to the use of synthetic insecticides, to offer growers effective tools with which to monitor and control vine weevil. In particular, the influence of visual cues on vine weevil behaviour is investigated to develop an improved monitoring tool of this pest. Similarly, the chemical ecology of this species was studied to identify semiochemicals that can be used as a lure to improve monitoring tool efficacy. To achieve this, host and non-host plants as well as vine weevil produced volatiles were investigated. In addition, a bioinsecticide based on garlic extracts (Pitcher GR®) was evaluated under laboratory and glasshouse conditions in order to determine its potential as a vine weevil control. Finally, the efficacy of EPNs at controlling vine weevil larvae is assessed in six commercially available peat-free growing media. Results showed that visual (monitoring tool shade/colour, height and diameter as well as the effect of monitoring tool density) and olfactory (host plant and apple sauce) cues influence vine weevil monitoring tool efficacy. The garlic-based product was effective against vine weevil eggs and larvae under laboratory conditions, but its efficacy under glasshouse conditions requires further investigation to optimise its use against vine weevil. When the efficacy of EPNs was evaluated in six commercially available peat alternative growing media, EPNS were found to survive in all the growing media types. However, dispersal was affected by growing media, with Coir and John Innes Number 2 having a negative effect on EPNs. In addition, when S. kraussei was tested under glasshouse conditions, the EPN was effective at controlling vine weevil in all growing media tested. This study provides the basis to develop an enhanced monitoring tool that incorporates both visual and olfactory cues, while also promoting the effective use of biopesticides (e.g., garlic-based bioinsecticides) and biological controls (EPNs) for vine weevil control. However, further research is necessary to optimise vine weevil monitoring and management strategies.

Item Type:	Thesis (Doctoral)
Divisions:	Agriculture and Environment (from 1.08.20)
Depositing User:	Mrs Susan Howe
Date Deposited:	04 Mar 2025 11:12
Last Modified:	04 Mar 2025 11:12
URI:	https://hau.repository.guildhe.ac.uk/id/eprint/18179

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