- Title
- The ecology and control of Opuntia Aurantiaca in South Africa in relation to the cochineal insect, Dactylopius Austrinus
- Creator
- Zimmermann, Helmuth G
- ThesisAdvisor
- Moran, V C
- Subject
- Cochineal insect -- South Africa Cactus -- South Africa Weeds -- Control -- South Africa Insect-plant relationships
- Date
- 1982
- Type
- Thesis
- Type
- Doctoral
- Type
- PhD
- Identifier
- vital:5612
- Identifier
- http://hdl.handle.net/10962/d1003061
- Description
- The cochineal insect Dactylopius austrinus De Lotto, which was released on jointed cactus, Opuntia aurantiaca Lindley, in South Africa in 1932, failed to bring the weed under an acceptable level of control in spite of the encouraging results during the first few years after release. The reasons for this apparent failure were never clearly understood. In 1957 the State embarked on an intensive herbicidal control programme which is still in force today. This sustained and expensive programme has undoubtedly reduced the density of the weed in most areas but has failed to solve the problem and the plant continues to expand its range. The biological control of o. aurantiaca in South Africa has been fundamentally influenced by this chemical control campaign. The relationship between chemical and biological control methods is reported in this study.
- Format
- 159 leaves, pdf
- Publisher
- Rhodes University, Faculty of Science, Zoology and Entomology
- Language
- English
- Rights
- Zimmermann, Helmuth G
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|---|---|---|---|---|---|---|---|
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