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dc.contributor.authorHarcourt, Stephen John
dc.date.accessioned2010-05-03T01:12:17Z
dc.date.available2010-05-03T01:12:17Z
dc.date.issued2002
dc.identifier.urihttps://hdl.handle.net/10182/1790
dc.description.abstractVespula germanica (F.) (German wasp) and V. vulgaris (L.) (common wasp) are major pests in New Zealand. They damage crops, have a significant impact on the biodiversity of native ecosystems and present a significant health hazard by stinging people and animals. Efforts to control them, both chemically and biologically, have not been as effective as initially hoped. This research contributes to a larger programme studying the potential of entomopathogenic microbes for the control of German and common wasps in New Zealand. This study has demonstrated the potential and limitations which exist for control of wasps using microbial pathogens. Effective pathogens were identified and disease transmission quantified in bioassays. Behavioural and physiological adaptations of wasps were investigated as resistance mechanisms to disease. Three species of fungi (Beauveria bassiana, Aspergillus flavus and Metarhizium anisopliae) were identified as having potential to kill workers and larvae and severely disrupt the colony. In laboratory trials, fungi and bacteria were readily transmitted between workers and larvae and among workers. Workers and larvae, individually, possess few resistance mechanisms capable of suppressing a mass infection of pathogenic fungi. No tested bacteria were pathogenic to adult wasps. Although B. bassiana was extremely pathogenic in bioassays, behavioural adaptations of wasp workers and larvae restricted proliferation of fungi in a healthy nest. Anomalies in behaviour when removing sporulating or infectious cadavers indicate a 'window-of-opportunity' for the dissemination of disease if the fungus could achieve maturity. However, getting sufficient inoculum into the nest and achieving widespread sporulation to establish an epizootic will be a significant challenge. All of the bacteria tested were susceptible to antibiotics in larval saliva, and therefore not significantly pathogenic to wasps. Significant inhibitory effects of venom against A. flavus were identified, but no evidence of its use in the nest could be found. A more cryptic and infectious disease, such as a bacterium or microsporidian, holds the greatest potential for future control efforts. It is apparent that, in order to establish an infection capable of developing into an epizootic in wasp nests, a microbe needs to be gradually invasive, readily transmitted, a prolific replicator, cryptic and have little impact on host behaviour leading up to maturation. Limitations to the current use of pathogens for wasp control may be overcome by strain selection and development of delivery systems. Pathogens have the potential to complement and enhance existing biological control programmes, but much research is needed to realise this potential.en
dc.language.isoenen
dc.publisherLincoln Universityen
dc.rights.urihttps://researcharchive.lincoln.ac.nz/page/rights
dc.subjectVespula vulgaris (L.)en
dc.subjectVespula germanica (F.)en
dc.subjectBeauveria bassianaen
dc.subjectAspergillus flavusen
dc.subjectSerratia marcescensen
dc.subjectfungusen
dc.subjectbacteriaen
dc.subjectbioassayen
dc.subjectentomopathogenen
dc.subjectmortalityen
dc.subjectvenomen
dc.subjectlarval salivaen
dc.subjecthygienic behaviouren
dc.subjectnecrophoriaen
dc.subjectnecrophagiaen
dc.subjecttrophallaxisen
dc.titleDisease mitigation and pathogenic control in German and common wasps, Vespula germanica and V. vulgaris (Hymenoptera: Vespidae)en
dc.typeThesisen
thesis.degree.grantorLincoln Universityen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen
dc.subject.marsdenFields of Research::270000 Biological Sciences::270300 Microbiology::270307 Microbial ecologyen
dc.subject.marsdenFields of Research::300000 Agricultural, Veterinary and Environmental Sciences::300200 Crop and Pasture Production::300204 Plant protection (pests, diseases and weeds)en
dc.subject.marsdenFields of Research::270000 Biological Sciences::270400 Botany::270403 Plant pathologyen
dc.subject.marsdenFields of Research::270000 Biological Sciences::270500 Zoology::270505 Entomologyen
lu.thesis.supervisorChapman, Bruce
lu.thesis.supervisorScott, Eric
lu.thesis.supervisorHarris, Richard
lu.contributor.unitDepartment of Ecologyen
dc.rights.accessRightsDigital thesis can be viewed by current staff and students of Lincoln University only. Print copy available for reading in Lincoln University Library. en


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