Plutella xylostella attacks many cruciferous plants, reduces crop yields significantly and leads to estimated economic losses of around £4-5 billion yearly. Diamide insecticides are widely used for the control of Lepidoptera pests such as Plutella xylostella globally. Chloranthraniliprole (CHL) is one of the most commonly used commercial diamide insecticide however, cases of resistance have started emerging in the fields where this insecticide is being used. Insecticide resistance is a major challenge in pest control and it eventually renders insecticides ineffective.
The research described in this thesis was motivated by the urgent need to gain insight into the sources of diamide insecticide resistance as the hypothesis on which the research is based was that an early understanding of the causes of insecticide resistance could help in designing appropriate interventions to solve this challenge.
In this thesis, I will explain how I used structure activity relationship (SAR) studies and built on the knowledge of protein profiling to develop and synthesise a range of small molecules that served as insecticidal probes. I will also elaborate on how the real-life application of one of these probe molecules was demonstrated by using the probe molecule to carry out in-gel labelling experiments in Plutella xylostella. Finally, I describe how the developed probe molecules were used for proteomics experiments that led to the identification of key metabolising enzymes which may be associated with diamide resistance in Plutella xylostella.