VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.
 

Impact of the microbial pesticide Bacillus thruingiensis Berliner subsp. kurstaki on Hymenopterous parasites of the imported cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae)

Simple item page
dc.contributor.authorMcDonald, Richard C.en
dc.contributor.committeechairKok, Loke T.en
dc.contributor.committeememberEaton, Judith L.en
dc.contributor.committeememberO’Dell, Charles R.en
dc.contributor.committeememberPienkowski, Robert L.en
dc.contributor.committeememberRavlin, F. Williamen
dc.contributor.committeememberYousten, Al A.en
dc.contributor.departmentEntomologyen
dc.date.accessioned2014-03-14T21:21:27Zen
dc.date.adate2005-10-19en
dc.date.available2014-03-14T21:21:27Zen
dc.date.issued1990en
dc.date.rdate2005-10-19en
dc.date.sdate2005-10-19en
dc.description.abstractThree formulations of Bacillus thuringiensis Berliner subsp. kurstaki (Dipel 4L, Dipel 2X, and ABG-6167) were compared with the synthetic pyrethroid perrnethrin ( common name Pounce 3. 2 EC) for insecticidal activity and impact upon parasitism of the imported cabbageworrn, Pieris rapae (L.) (Lepidoptera: Pieridae) in field broccoli (CV Packrnan) from fall 1986 to spring 1988. Perrnethrin, Dipel 4L, and ABG-6167 were not significantly different in their efficacy towards imported cabbageworm larvae. Parasitization of P. rapae by the larval parasite Cotesia glomerata (L.) (Hymenoptera: Braconidae) and the pupal parasite Pteromalus puparum (L.) (Hyrnenoptera: Pteromalidae) continued after spraying in the B. thuringiensis plots, but was not significantly different from perrnethrin. However, 100% of the P. rapae chrysalids recovered were parasitized by P. puparum. The impact of seasonal hyperparasitism was compared between .Q. glomerata, and a Yugoslavian strain of Cotesia rubecula (Marshall), an exotic larval parasite of the imported cabbageworm. Four hyperparasites, two of them attacking both~. glomerata and~. rubecula, were found in field plots from 1986-1988. The level of hyperparasitization for the two primary parasites was significantly different. Hyperparasitization averaged only 8.1% for C. glomerata from 1986-1988, but was 37. 9% for C. rubecula from 1987-1988. During the early- to mid-season of 1988, hyperparasite activity was not detectable and C. rubecula outcompeted C. glomerata for hosts; but by mid-season, hyperparasite activity against C. rubecula increased to 100%, causing its populations to crash. C. glomerata then became the dominant parasite of P. rapae. C. rubecula was not recovered in 1989. Hyperparasites may be a limiting factor in establishing C. rubecula in southwestern Virginia. Mortality and successful pupation of P rapae fourth instars parasitized by C. rubecula to B. thuringiensis endotoxin at dosages of 850, 85, and 8.5 I.U./ml was examined. After day two, the LC<sub>50</sub>'s of parasitized fourth instars were approximately thirty times higher than that of unparasitized larvae and by day four, the LC<sub>50</sub> response of parasitized fourth instars was 180 times higher than unparasitized larvae. Twenty-five percent of parasitized fourth instars exposed to a concentration of 850 I.U./ml successfully pupated, compared to 76% at 85 I.U./ml and 69% at 8.5 I.U./ml. Parasitized fourth instar P. rapae consume less food and are therefore less susceptible to B. thuringiensis than unparasitized larvae at the same dosages.en
dc.description.degreePh. D.en
dc.format.extentxii, 121 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-10192005-113246en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10192005-113246/en
dc.identifier.urihttp://hdl.handle.net/10919/39942en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1990.M4345.pdfen
dc.relation.isformatofOCLC# 21328577en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1990.M4345en
dc.subject.lcshBroccoli -- Diseases and pestsen
dc.subject.lcshPieris rapaeen
dc.titleImpact of the microbial pesticide Bacillus thruingiensis Berliner subsp. kurstaki on Hymenopterous parasites of the imported cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae)en
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineEntomologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
LD5655.V856_1990.M4345.pdf
Size:
3.4 MB
Format:
Adobe Portable Document Format
Description:
Download

Collections

Doctoral Dissertations