The management of diamondback moth and other crucifer pests

Investigations of host plant-pest interactions have rarely used plant material in which the phenotype could be linked directly to a known genotype. However, in recent years, Arabidopsis thaliana has been intensively studied by molecular biologists and, as a result, there are a large number of genetically characterised A. thaliana mutants available to the scientific community. Our preliminary laboratory investigations have shown that A. thaliana can be used as a host plant by Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) and have demonstrated that larval period, pupal period and pupal weight measurements of P. xylostella developing on A. thaliana are comparable to those on Brassica rapa. These factors, combined with its relatively small size and easy growth, make A. thaliana a suitable model host plant for investigation of both genotypic and phenotypic factors which influence the biology of P. xylostella, the aim of our research. Our initial investigations have used the A. thaliana lines Col-0 and Col-5. These lines are genetically very similar except that Col-5 is homozygous for a gl1–1 mutant allele that is not present in Col-0. This mutant allele results in an absence of trichomes on the leaves and stem of the plant, which are normally present in Col-0. In our investigations, it was found that female larvae took significantly longer to develop and produced lighter pupae on Col-0 compared with Col-5. However, this effect was not seen in male insects. In both males and females, there was no significant effect on pupal period. It was also found that adults that had developed from larvae on Col-0 produced significantly fewer eggs than those that had developed on Col-5.