https://search.dev.ndltd.org/etd/lincoln/oai:researcharchive.lincoln.ac.nz:10182/1901
type: CreativeWork
name: Effect of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) on Diadegma semiclausum (Hellen) (Hymenoptera: Ichneumonidae), a parasitoid of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae)
description: Investigation of the interactions among Plutella xylostella (host), Beauveria bassiana (pathogen) and Diadegma semiclausum (parasitoid) was the aim of this thesis. The pathogenicity of B. bassiana to P. xylostella larvae and D. semiclausum females, the direct and indirect effect of the pathogen on the fecundity, longevity, development and survival of the parasitoid, behavioural responses of the parasitoid to fungus-infected and uninfected host larvae and the ability of parasitoids to disseminate fungal conidia among host larvae were investigated under laboratory conditions. The compatibility of B. bassiana with D. semiclausum for the management of P. xylostella larvae was studied under field cage conditions. Nine B. bassiana isolates (three from New Zealand and six acquired from the USA),were tested against P. xylostella larvae under laboratory conditions. All tested isolates were pathogenic. The New Zealand isolates, none of which originated from P. xylostella, were equally effective as the isolate from the USA that originated from P. xylostella. New Zealand isolate F226 had an LT₅₀ value of 3.6 days compared with the USA strains with LT₅₀ values between 4.0 - 5.0 days. When adult female parastoids were directly exposed to B. Bassiana isolates F226, F130, ARSEF 2729 and ARSEF 3288 parasitoids died within four days after treatment whereas untreated parasitoids survived 16.2 ± 1.2 days. The ability of parasitoids to discriminate between infected and uninfected larvae was investigated by using the bacterium Serratia marcescens as an oviposition marker. When D. semiclausum adults contaminated with bacteria were exposed to fungus-treated P. xylostella larvae in a choice test, the mean number of oviposition attempts over three hours made by the parasitoid (determined by the number of dead larvae with red pigmented colonies) was 4.31± 1.19 on infected larvae and 3.56 ± 1.06 on uninfected larvae. The results of the bacterial marker test showed D. semiclausum did not to dis…
abstract: Investigation of the interactions among Plutella xylostella (host), Beauveria bassiana (pathogen) and Diadegma semiclausum (parasitoid) was the aim of this thesis. The pathogenicity of B. bassiana to P. xylostella larvae and D. semiclausum females, the direct and indirect effect of the pathogen on the fecundity, longevity, development and survival of the parasitoid, behavioural responses of the parasitoid to fungus-infected and uninfected host larvae and the ability of parasitoids to disseminate fungal conidia among host larvae were investigated under laboratory conditions. The compatibility of B. bassiana with D. semiclausum for the management of P. xylostella larvae was studied under field cage conditions. Nine B. bassiana isolates (three from New Zealand and six acquired from the USA),were tested against P. xylostella larvae under laboratory conditions. All tested isolates were pathogenic. The New Zealand isolates, none of which originated from P. xylostella, were equally effective as the isolate from the USA that originated from P. xylostella. New Zealand isolate F226 had an LT₅₀ value of 3.6 days compared with the USA strains with LT₅₀ values between 4.0 - 5.0 days. When adult female parastoids were directly exposed to B. Bassiana isolates F226, F130, ARSEF 2729 and ARSEF 3288 parasitoids died within four days after treatment whereas untreated parasitoids survived 16.2 ± 1.2 days. The ability of parasitoids to discriminate between infected and uninfected larvae was investigated by using the bacterium Serratia marcescens as an oviposition marker. When D. semiclausum adults contaminated with bacteria were exposed to fungus-treated P. xylostella larvae in a choice test, the mean number of oviposition attempts over three hours made by the parasitoid (determined by the number of dead larvae with red pigmented colonies) was 4.31± 1.19 on infected larvae and 3.56 ± 1.06 on uninfected larvae. The results of the bacterial marker test showed D. semiclausum did not to dis…
author: Madurappulige, Dharmadasa
language: en
keywords: Diadegma semiclausum, Beauveria bassiana, interactions, bioassay, biological control, mortality, mycosis, parasitoid longevity, parasitoid behaviour, ecological susceptibility, Plutella xylostella, LC₅₀, LT₅₀, diamondback moth
date published: 2005
date modified: 2026-07-24T02:50:30Z
provider: Lincoln University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Lincoln University

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property ID: Handle
value: https://hdl.handle.net/10182/1901