The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape

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dc.contributor.advisorVon Wechmar, M Barbaraen_ZA
dc.contributor.authorLaubscher, Jacobus Martinen_ZA
dc.date.accessioned2016-09-28T19:05:20Z
dc.date.available2016-09-28T19:05:20Z
dc.date.issued1992en_ZA
dc.description.abstractAphid lethal paralysis virus (ALPV) could be detected by indirect immunofluorescent technique in dissected aphids. This technique was found to be more sensitive when compared to DAS-ELISA. The choice of a sensitive, low cost .detection method was of importance to test for low levels of virus in infected aphid body tissues where inapparent infection could cause detection problems. ALPV was visualized in ultrathin sections of diseased aphid body tissues by immunocytochemistry utilizing immunogold label. ALPV antigen was detected in the ovariole tissue, tracheocytes, symbionts of the mycetocytes, fat body cells, brain tissue, nerve tissue and stomach epithelial tissue. Virions were detected predominantly in the cytoplasm but were also found in the nucleus. ALPV antigen was not detected in muscle fibres or mitochondria. ALPV and Rhopalosiphum padi virus (RhPV) are transmitted transovarially. Different incidences of transmissions of ALPV were obtained for R. padi (2996) and Sitobion avenae (1696) and ALPV infections dramatically reduced the longevity and fecundity of these aphids. Infected apterous R. padi aphids were more fecund than alate aphids of the same clone. The percentage of viral infections in different aphid species (R. padi, S. avenae and Diuraphis noxia) was positively associated with temperature; higher temperatures dramatically increased the incidence of ALPV and RhPV and vice versa. The influence of ALPV on a natural R. padi aphid population was found to reduce the population size by 4996. This reduction coincided with a high death factor (70) of aphids per plant. A dramatic decline in R. padi aphid numbers and a high incidence of ALPV present in this aphid population was experienced. Parasitic fungal infections peaked at a later stage than ALPV, and a level of 21 parasitized aphids per plant was reached during this period. This appears to indicate that the presence of ALPV contributes to limit population development in R. padi aphids. Similar results were obtained with S. avenae aphids. Based on this data, ALPV could be considered as a major growth limiting factor in the development of small grain aphid populations in the western Cape. If the presence of the virus is taken into consideration, it could influence pest management strategies directly.en_ZA
dc.identifier.apacitationLaubscher, J. M. (1992). <i>The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/21980en_ZA
dc.identifier.chicagocitationLaubscher, Jacobus Martin. <i>"The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1992. http://hdl.handle.net/11427/21980en_ZA
dc.identifier.citationLaubscher, J. 1992. The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Laubscher, Jacobus Martin AB - Aphid lethal paralysis virus (ALPV) could be detected by indirect immunofluorescent technique in dissected aphids. This technique was found to be more sensitive when compared to DAS-ELISA. The choice of a sensitive, low cost .detection method was of importance to test for low levels of virus in infected aphid body tissues where inapparent infection could cause detection problems. ALPV was visualized in ultrathin sections of diseased aphid body tissues by immunocytochemistry utilizing immunogold label. ALPV antigen was detected in the ovariole tissue, tracheocytes, symbionts of the mycetocytes, fat body cells, brain tissue, nerve tissue and stomach epithelial tissue. Virions were detected predominantly in the cytoplasm but were also found in the nucleus. ALPV antigen was not detected in muscle fibres or mitochondria. ALPV and Rhopalosiphum padi virus (RhPV) are transmitted transovarially. Different incidences of transmissions of ALPV were obtained for R. padi (2996) and Sitobion avenae (1696) and ALPV infections dramatically reduced the longevity and fecundity of these aphids. Infected apterous R. padi aphids were more fecund than alate aphids of the same clone. The percentage of viral infections in different aphid species (R. padi, S. avenae and Diuraphis noxia) was positively associated with temperature; higher temperatures dramatically increased the incidence of ALPV and RhPV and vice versa. The influence of ALPV on a natural R. padi aphid population was found to reduce the population size by 4996. This reduction coincided with a high death factor (70) of aphids per plant. A dramatic decline in R. padi aphid numbers and a high incidence of ALPV present in this aphid population was experienced. Parasitic fungal infections peaked at a later stage than ALPV, and a level of 21 parasitized aphids per plant was reached during this period. This appears to indicate that the presence of ALPV contributes to limit population development in R. padi aphids. Similar results were obtained with S. avenae aphids. Based on this data, ALPV could be considered as a major growth limiting factor in the development of small grain aphid populations in the western Cape. If the presence of the virus is taken into consideration, it could influence pest management strategies directly. DA - 1992 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1992 T1 - The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape TI - The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape UR - http://hdl.handle.net/11427/21980 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21980
dc.identifier.vancouvercitationLaubscher JM. The effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Cape. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1992 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21980en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMicrobiologyen_ZA
dc.titleThe effect of aphid lethal paralysis virus (ALPV) on the biology of grain aphids in the Western Capeen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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