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Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa
Dissertation (MSc)--University of Pretoria, 2008.
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University of Pretoria
2013
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| _version_ | 1867613596710600704 |
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| access_status_str | Open Access |
| author2 | Kappmeier, Karin |
| author_browse | Kappmeier, Karin |
| author_facet | Kappmeier, Karin |
| collection | Thesis |
| dc_rights_str_mv | © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2008. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/26859 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:38:39.945Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/26859 Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa Kappmeier, Karin Penzhorn, Barend Louis DeBeerC@arc.agric.za De Beer, Chantel Janet Rivers Ipm South Africa Farmers Integrated pest management Livestock Blackflies UCTD Dissertation (MSc)--University of Pretoria, 2008. Blackflies (Diptera: Simuliidae) are major pests in the livestock and labour-intensive farming systems along the major rivers in South Africa. At present, blackflies are controlled with the larvicide Bacillus thuringienses var. israelensis (B.t.i.). As part of establishing an environmentally friendly and cost-effective Integrated Pest Management (IPM) program against blackflies, investigations were initiated to support the present blackfly-control strategy in South Africa. Emphasis was placed on potential predators and parasites of the blackflies’ aquatic stages. Questionnaires were presented to livestock farmers along the Vaal and Orange Rivers to determine public views concerning blackfly annoyance. Furthermore, blackfly populations at thirteen sites along the Orange River, twelve along the Vaal River and one site along each of two tributaries to the Vaal River, namely the Riet and Harts Rivers, were monitored seasonally for one year. The abundance of the aquatic stages of blackflies and potential predators on stones and vegetation in the river was determined using the 10-point visual ranking system of Palmer (1994) and the South African Scoring system (SASS 5), respectively. The abundance of algae as well as other environmental factors, namely water flow, water temperature and turbidity, were also monitored. Farmers who were contacted along both the Vaal and Orange rivers indicated that they experience severe blackfly problems during the summer months and that the majority of farmers were not aware of any products available that could protect their animals against blackfly attacks. The farmers also indicated that they were willing to be involved in blackfly research to improve this situation. Blackfly larvae and pupae were found in high abundance in both the Vaal and Orange Rivers. Simulium chutteri was the most abundant species in the Orange River and S. adersi in the Vaal River. In both the Vaal and Orange Rivers there was no significant correlation between immature blackfly abundance and water flow and turbidity. Water temperature also played a role in the seasonal build-up of blackflies in the winter months. The three most abundant algae classes were Bacillariophyceae, Chlorophyceae and Cyanophyceae. Cyanophyceae was the only algae group that had a negative correlation with blackfly immature abundance in the Orange River; this was not statistically significant. There were no negative correlations in the Vaal River. In both the Vaal and Orange rivers, blackflies were infected with Mermithidae nematodes and Microspora protozoans. In the Vaal River, the infection prevalence in natural conditions was the highest for Microspora and in the Orange River the highest for Mermithidae. The most important families of blackfly predators identified were Hydropsychidae and Gyrinidae. Hydropsychidae was the only family recorded in high abundance but this predator had no effect on abundance of immature blackfly. Gyrinidae gave a negative correlation with immature blackfly abundance; however, this was not significant. The biological control agents identified in this research need to be evaluated further for use in an IPM approach with the current control system, B.t.i. Copyright Veterinary Tropical Diseases unrestricted 2013-09-07T08:25:09Z 2009-09-04 2013-09-07T08:25:09Z 2009-04-29 2009-09-04 2009-07-30 Dissertation De Beer, CJ 2008, Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/26859 > E1350/gm http://hdl.handle.net/2263/26859 http://upetd.up.ac.za/thesis/available/etd-07302009-154218/ © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Rivers Ipm South Africa Farmers Integrated pest management Livestock Blackflies UCTD Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title | Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title_full | Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title_fullStr | Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title_full_unstemmed | Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title_short | Assessment of blackfly (Diptera : Simuliidae) problem status and potential biological control agents along the Vaal and Orange Rivers in South Africa |
| title_sort | assessment of blackfly diptera simuliidae problem status and potential biological control agents along the vaal and orange rivers in south africa |
| topic | Rivers Ipm South Africa Farmers Integrated pest management Livestock Blackflies UCTD |
| url | http://hdl.handle.net/2263/26859 http://upetd.up.ac.za/thesis/available/etd-07302009-154218/ |