Molecular Markers for Lygus Parasitoids to Assess Host Specificity of Candidate Entomophagous Biological Control Agents
These associations can be difficult to study using conventional methods. Morphological similarity of related parasitoids prevents species-level identification by dissection. Host rearing is time-consuming and can result in high levels of host and parasitoid mortality. To facilitate identification of immature Peristenus spp. in their hosts, a multiplex PCR assay was developed. This assay provided a specific and sensitive tool to screen individual insects for three parasitoid species simultaneously.
To validate the utility of the multiplex PCR assay in ecological host range studies, parasitism and parasitoid species composition obtained using conventional and molecular techniques were compared. Molecular methods compared favorably with conventional methods; however, more complete species composition information was available with the multiplex assay. To improve the quality of risk assessment studies and extract the most accurate ecological host range data, molecular methods were used to evaluate host-parasitoid associations in mirid populations collected in two ecoregions. Several new host-parasitoid associations were recorded for P. digoneutis and P. relictus, but parasitism of non-target mirids was low.
Parasitism of the target host collected from different plant species was evaluated to help clarify Peristenus host-plant associations. Despite the investigation of three different host plant species, no difference was observed in the parasitism level or parasitoid species composition in L. rugulipennis. The post-release utility of the multiplex assay was investigated in Canada, where Lygus parasitoids may have dispersed following release in the USA. To confirm establishment, samples were analyzed using the multiplex PCR assay, and P. digoneutis was detected for the first time in southern Ontario.
Advisor:Messier, François; Kuhlmann, Ulrich; Gillott, Cedric; Davis, Arthur R.; Erlandson, Martin
School:University of Saskatchewan
School Location:Canada - Saskatchewan
Source Type:Master's Thesis
Keywords:multiplex pcr biological control molecular diagnostics peristenus
Date of Publication:04/24/2007