Molecular identification of Azolla invasions in Africa: The Azolla specialist, Stenopelmus rufinasus proves to be an excellent taxonomist
- Madeira, P T, Dray, F Allen, Coetzee, Julie A, Paterson, Iain D, Tipping, Philip W
- Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
- Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
- Full Text:
- Date Issued: 2016
- Authors: Madeira, P T , Dray, F Allen , Coetzee, Julie A , Paterson, Iain D , Tipping, Philip W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424765 , vital:72182 , xlink:href="https://doi.org/10.1016/j.sajb.2016.03.007"
- Description: Biological control of Azolla filiculoides in South Africa with the Azolla specialist Stenopelmus rufinasus has been highly successful. However, field surveys showed that the agent utilized another Azolla species, thought to be the native Azolla pinnata subsp. africana, which contradicted host specificity trials. It is notoriously difficult to determine Azolla species based on morphology so genetic analyses were required to confirm the identity of the Azolla used by the agent. Extensive sampling was conducted and samples were sequenced at the trnL-trnF and trnG-trnR chloroplastic regions and the nuclear ITS1 region. Current literature reported A. filiculoides as the only Section Azolla species in southern Africa but 24 samples were identified as Azolla cristata, an introduced species within Section Azolla that was not used during host specificity trials. A. pinnata subsp. africana was only located at one site in southern Africa, while the alien A. pinnata subsp. asiatica was located at three. What was thought to be A. pinnata subsp. africana was in fact A. cristata, a closer relative of A. filiculoides and a suitable host according to specificity trials. This study confirms that S. rufinasus is a proficient Azolla taxonomist but also supports the use of molecular techniques for resolving taxonomic conundrums.
- Full Text:
- Date Issued: 2016
The distribution and abundance of the stem-galling fly, Cecidochares connexa (Macquart)(Diptera: Tephritidae), a biological control agent of Chromolaena odorata (L.)(Asteraceae), in Ghana
- Aigbedion-Atalor, Pascal O, Wilson, David D, Eziah, Vincent Y, Day, Michael D, Paterson, Iain D
- Authors: Aigbedion-Atalor, Pascal O , Wilson, David D , Eziah, Vincent Y , Day, Michael D , Paterson, Iain D
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407074 , vital:70334 , xlink:href="https://hdl.handle.net/10520/EJC-113112d1da"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae: Eupatorieae) is one of the worst invasive weeds in West Africa, and a serious biotic threat to food security. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), a biological control agent for C. odorata, was released in the Ivory Coast in 2003 and first detected in Ghana in 2014. The spatiotemporal distribution and abundance of C. connexa in Ghana was determined by country-wide surveys from 2015 to 2016. Galls were found in varying densities across Ghana but gall densities were consistently low east of Lake Volta. A limited survey conducted in the extreme west of Togo in 2016, found the gall fly also in low numbers. There was a significant correlation between C. connexa gall densities and the distance from the release sites in the Ivory Coast. The distribution and abundance of the gall fly in Ghana could be explained by its spread from the original release sites over time and/or the much drier conditions east of Lake Volta. Cecidochares connexa has dispersed a distance of about 1000 km over a 10-year period and, while there is some evidence that the gall fly is still dispersing towards the east, its range and population size could be limited by the dry climatic conditions in the east of Ghana and in Togo. Actively redistributing the agent over this dry corridor to the more humid and higher rainfall areas of Nigeria, may result in the spread of this agent through the rest of West and Central Africa, thereby aiding the control of C. odorata in the region.
- Full Text:
- Date Issued: 2018
- Authors: Aigbedion-Atalor, Pascal O , Wilson, David D , Eziah, Vincent Y , Day, Michael D , Paterson, Iain D
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407074 , vital:70334 , xlink:href="https://hdl.handle.net/10520/EJC-113112d1da"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae: Eupatorieae) is one of the worst invasive weeds in West Africa, and a serious biotic threat to food security. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), a biological control agent for C. odorata, was released in the Ivory Coast in 2003 and first detected in Ghana in 2014. The spatiotemporal distribution and abundance of C. connexa in Ghana was determined by country-wide surveys from 2015 to 2016. Galls were found in varying densities across Ghana but gall densities were consistently low east of Lake Volta. A limited survey conducted in the extreme west of Togo in 2016, found the gall fly also in low numbers. There was a significant correlation between C. connexa gall densities and the distance from the release sites in the Ivory Coast. The distribution and abundance of the gall fly in Ghana could be explained by its spread from the original release sites over time and/or the much drier conditions east of Lake Volta. Cecidochares connexa has dispersed a distance of about 1000 km over a 10-year period and, while there is some evidence that the gall fly is still dispersing towards the east, its range and population size could be limited by the dry climatic conditions in the east of Ghana and in Togo. Actively redistributing the agent over this dry corridor to the more humid and higher rainfall areas of Nigeria, may result in the spread of this agent through the rest of West and Central Africa, thereby aiding the control of C. odorata in the region.
- Full Text:
- Date Issued: 2018
West African arthropods hold promise as biological control agents for an invasive tree in the Pacific Islands
- Paterson, Iain D, Paynter, Quentin, Neser, Stefan, Akpabey, Felix J, Compton, Stephen G, Orapa, W
- Authors: Paterson, Iain D , Paynter, Quentin , Neser, Stefan , Akpabey, Felix J , Compton, Stephen G , Orapa, W
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407119 , vital:70338 , xlink:href="https://hdl.handle.net/10520/EJC-639c91613"
- Description: African tulip tree, Spathodea campanulata Beauv. (Bignoniaceae), is a large tree of secondary forests, forest edges and savannas that is indigenous to Central and West Africa (Bidgood 1994). It has been widely utilised as an ornamental plant due to its beautiful flowers, fast growth and relative ease of cultivation, as a shade tree in parks and coffee plantations, and as a living fencepost (Francis 1990). Naturalisation has often followed cultivation of the plant, which is now established outside of the native range in Africa (Hedberg et al. 2006), the Caribbean (Francis 1990; Labrada and Medina 2009) and many Pacific islands (Meyer 2004), including Hawaii, Papua New Guinea, Fiji, Samoa, Tonga,Vanuatu and Tahiti (Lowe et al. 2000; Dovey et al. 2004; Labrada and Medina 2009). On some of these islands it has become a destructive weed, invading indigenous forests and having a severe impact on agricultural production (Labrada and Medina 2009; Larrue et al. 2014). This has resulted in African tulip tree being recognised as one of the 100 worst alien invasive species worldwide, along with only 30 other terrestrial plants (Lowe et al. 2000).
- Full Text:
- Date Issued: 2017
- Authors: Paterson, Iain D , Paynter, Quentin , Neser, Stefan , Akpabey, Felix J , Compton, Stephen G , Orapa, W
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407119 , vital:70338 , xlink:href="https://hdl.handle.net/10520/EJC-639c91613"
- Description: African tulip tree, Spathodea campanulata Beauv. (Bignoniaceae), is a large tree of secondary forests, forest edges and savannas that is indigenous to Central and West Africa (Bidgood 1994). It has been widely utilised as an ornamental plant due to its beautiful flowers, fast growth and relative ease of cultivation, as a shade tree in parks and coffee plantations, and as a living fencepost (Francis 1990). Naturalisation has often followed cultivation of the plant, which is now established outside of the native range in Africa (Hedberg et al. 2006), the Caribbean (Francis 1990; Labrada and Medina 2009) and many Pacific islands (Meyer 2004), including Hawaii, Papua New Guinea, Fiji, Samoa, Tonga,Vanuatu and Tahiti (Lowe et al. 2000; Dovey et al. 2004; Labrada and Medina 2009). On some of these islands it has become a destructive weed, invading indigenous forests and having a severe impact on agricultural production (Labrada and Medina 2009; Larrue et al. 2014). This has resulted in African tulip tree being recognised as one of the 100 worst alien invasive species worldwide, along with only 30 other terrestrial plants (Lowe et al. 2000).
- Full Text:
- Date Issued: 2017
Eight decades of invasion by Chromolaena odorata (Asteraceae) and its biological control in West Africa: the story so far
- Aigbedion-Atalor, Pascal O, Adom, Medetissi, Day, Michael D, Uyi, Osariyekemwen O, Egbon, Ikponmwosa N, Idemudia, I, Igbinosa, Igho B, Paterson, Iain D, Braimah, Haruna, Wilson, David D, Zachariades, Costas
- Authors: Aigbedion-Atalor, Pascal O , Adom, Medetissi , Day, Michael D , Uyi, Osariyekemwen O , Egbon, Ikponmwosa N , Idemudia, I , Igbinosa, Igho B , Paterson, Iain D , Braimah, Haruna , Wilson, David D , Zachariades, Costas
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417450 , vital:71454 , xlink:href="https://doi.org/10.1080/09583157.2019.1670782"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) is a perennial weedy shrub of neotropical origin and a serious biotic threat in its invasive range. The Asian-West Africa (AWA) biotype of C. odorata present in West Africa is both morphologically and genetically different from the southern African (SA) biotype. The AWA biotype was first introduced into Nigeria in the late 1930s and rapidly spread across West Africa. Currently, 12 of the 16 countries in West Africa have been invaded, with significant negative effects on indigenous flora and fauna. However, locals in West Africa have found several uses for the weed. As chemical, physical and other conventional methods were unsustainable, costly and largely ineffective, three biological control agents, Apion brunneonigrum (Coleoptera: Brentidae), Pareuchaetes pseudoinsulata (Lepidoptera: Erebidae) and Cecidochares connexa (Diptera: Tephritidae), have been released in West Africa between the 1970s and the early 2000s. However, only C. connexa and P. pseudoinsulata established, contributing to the control of the weed, in six and four countries in West Africa respectively. Limited research funding, the absence of post-release evaluations of the established agents, and the ‘conflict of interest’ status of C. odorata (i.e. being beneficial for local use but damaging to ecosystem services and agriculture), are serious factors deterring the overall biological control effort. Here, using historical records and field surveys, we examine the invasion history, spread, impacts, and management of C. odorata in West Africa and make recommendations for the sustainable management of C. odorata in the region.
- Full Text:
- Date Issued: 2019
- Authors: Aigbedion-Atalor, Pascal O , Adom, Medetissi , Day, Michael D , Uyi, Osariyekemwen O , Egbon, Ikponmwosa N , Idemudia, I , Igbinosa, Igho B , Paterson, Iain D , Braimah, Haruna , Wilson, David D , Zachariades, Costas
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417450 , vital:71454 , xlink:href="https://doi.org/10.1080/09583157.2019.1670782"
- Description: Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) is a perennial weedy shrub of neotropical origin and a serious biotic threat in its invasive range. The Asian-West Africa (AWA) biotype of C. odorata present in West Africa is both morphologically and genetically different from the southern African (SA) biotype. The AWA biotype was first introduced into Nigeria in the late 1930s and rapidly spread across West Africa. Currently, 12 of the 16 countries in West Africa have been invaded, with significant negative effects on indigenous flora and fauna. However, locals in West Africa have found several uses for the weed. As chemical, physical and other conventional methods were unsustainable, costly and largely ineffective, three biological control agents, Apion brunneonigrum (Coleoptera: Brentidae), Pareuchaetes pseudoinsulata (Lepidoptera: Erebidae) and Cecidochares connexa (Diptera: Tephritidae), have been released in West Africa between the 1970s and the early 2000s. However, only C. connexa and P. pseudoinsulata established, contributing to the control of the weed, in six and four countries in West Africa respectively. Limited research funding, the absence of post-release evaluations of the established agents, and the ‘conflict of interest’ status of C. odorata (i.e. being beneficial for local use but damaging to ecosystem services and agriculture), are serious factors deterring the overall biological control effort. Here, using historical records and field surveys, we examine the invasion history, spread, impacts, and management of C. odorata in West Africa and make recommendations for the sustainable management of C. odorata in the region.
- Full Text:
- Date Issued: 2019
More than a century of biological control against invasive alien plants in South Africa: a synoptic view of what has been accomplished
- Hill, Martin P, Moran, V Clifford, Hoffmann, John H, Neser, Stefan, Zimmermann, Helmuth G, Simelane, David O, Klein, Hildegard, Zachariades, Costas, Wood, Alan R, Byrne, Marcus J, Paterson, Iain D, Martin, Grant D, Coetzee, Julie A
- Authors: Hill, Martin P , Moran, V Clifford , Hoffmann, John H , Neser, Stefan , Zimmermann, Helmuth G , Simelane, David O , Klein, Hildegard , Zachariades, Costas , Wood, Alan R , Byrne, Marcus J , Paterson, Iain D , Martin, Grant D , Coetzee, Julie A
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176260 , vital:42679 , ISBN 978-3-030-32394-3 , 10.1007/978-3-030-32394-3
- Description: Invasive alien plant species negatively affect agricultural production, degrade conservation areas, reduce water supplies, and increase the intensity of wild fires. Since 1913, biological control agents ie plant-feeding insects, mites, and fungal pathogens, have been deployed in South Africa to supplement other management practices (herbicides and mechanical controls) used against these invasive plant species. We do not describe the biological control agent species.
- Full Text: false
- Date Issued: 2020
- Authors: Hill, Martin P , Moran, V Clifford , Hoffmann, John H , Neser, Stefan , Zimmermann, Helmuth G , Simelane, David O , Klein, Hildegard , Zachariades, Costas , Wood, Alan R , Byrne, Marcus J , Paterson, Iain D , Martin, Grant D , Coetzee, Julie A
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176260 , vital:42679 , ISBN 978-3-030-32394-3 , 10.1007/978-3-030-32394-3
- Description: Invasive alien plant species negatively affect agricultural production, degrade conservation areas, reduce water supplies, and increase the intensity of wild fires. Since 1913, biological control agents ie plant-feeding insects, mites, and fungal pathogens, have been deployed in South Africa to supplement other management practices (herbicides and mechanical controls) used against these invasive plant species. We do not describe the biological control agent species.
- Full Text: false
- Date Issued: 2020
Addressing the red flags in cochineal identification: The use of molecular techniques to identify cochineal insects that are used as biological control agents for invasive alien cacti
- van Steenderen, Clarke J M, Paterson, Iain D, Edwards, Shelley, Day, Michael D
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, Michael D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, Michael D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021
ISSRs indicate that Chromolaena odorata invading southern Africa originates in Jamaica or Cuba
- Paterson, Iain D, Zachariades, Costas
- Authors: Paterson, Iain D , Zachariades, Costas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Zachariades, Costas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014
Biological control of South African plants that are invasive elsewhere in the world: A review of earlier and current programmes
- Olckers, Terence, Coetzee, Julie A, Egli, Daniella, Martin, Grant D, Paterson, Iain D, Sutton, Guy F, Wood, Alan R
- Authors: Olckers, Terence , Coetzee, Julie A , Egli, Daniella , Martin, Grant D , Paterson, Iain D , Sutton, Guy F , Wood, Alan R
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414336 , vital:71137 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a21"
- Description: South Africa supports a rich floral diversity, with 21 643 native plant taxa that include a high proportion (76.3%) of endemic species, and many of these favoured as ornamentals, both locally and globally. Consequently, South Africa has contributed substantially to global plant invasions, with 1093 native taxa (5% of all species) naturalized in other countries. At least 80 taxa are invasive in natural or semi-natural ecosystems elsewhere, while an additional 132 taxa are potentially invasive. Of the global naturalized flora, 8.2% originate from South Africa and largely comprise species of Poaceae, Asteraceae, Iridaceae and Fabaceae. Australia, in particular, but also Europe and North America are major recipients of South African weeds. However, few countries have targeted South African plants for biological control (biocontrol), with most efforts undertaken by Australia. Previous and current targets have involved only 26 species with 17 agents (15 insects, one mite and one rust fungus) of South African origin released on five target species in Australia and the United States of America. South Africa’s history of weed biocontrol, together with a large cohort of active scientists, is currently facilitating several internationally funded programmes targeting invasive plants of South African origin. In particular, the recently inaugurated Centre for Biological Control at Rhodes University and the University of KwaZulu-Natal have provided the impetus for novel efforts on five new target species and renewed efforts on four previously targeted species. In this contribution, we review the history of earlier biocontrol programmes against weeds of South African origin and the status of projects currently in progress in South Africa.
- Full Text:
- Date Issued: 2021
- Authors: Olckers, Terence , Coetzee, Julie A , Egli, Daniella , Martin, Grant D , Paterson, Iain D , Sutton, Guy F , Wood, Alan R
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414336 , vital:71137 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a21"
- Description: South Africa supports a rich floral diversity, with 21 643 native plant taxa that include a high proportion (76.3%) of endemic species, and many of these favoured as ornamentals, both locally and globally. Consequently, South Africa has contributed substantially to global plant invasions, with 1093 native taxa (5% of all species) naturalized in other countries. At least 80 taxa are invasive in natural or semi-natural ecosystems elsewhere, while an additional 132 taxa are potentially invasive. Of the global naturalized flora, 8.2% originate from South Africa and largely comprise species of Poaceae, Asteraceae, Iridaceae and Fabaceae. Australia, in particular, but also Europe and North America are major recipients of South African weeds. However, few countries have targeted South African plants for biological control (biocontrol), with most efforts undertaken by Australia. Previous and current targets have involved only 26 species with 17 agents (15 insects, one mite and one rust fungus) of South African origin released on five target species in Australia and the United States of America. South Africa’s history of weed biocontrol, together with a large cohort of active scientists, is currently facilitating several internationally funded programmes targeting invasive plants of South African origin. In particular, the recently inaugurated Centre for Biological Control at Rhodes University and the University of KwaZulu-Natal have provided the impetus for novel efforts on five new target species and renewed efforts on four previously targeted species. In this contribution, we review the history of earlier biocontrol programmes against weeds of South African origin and the status of projects currently in progress in South Africa.
- Full Text:
- Date Issued: 2021
Cryptic species of a water hyacinth biological control agent revealed in South Africa: host specificity, impact, and thermal tolerance
- Paterson, Iain D, Coetzee, Julie A, Weyl, Philip S R, Griffith, Tamzin C, Voogt, Nina, Hill, Martin P
- Authors: Paterson, Iain D , Coetzee, Julie A , Weyl, Philip S R , Griffith, Tamzin C , Voogt, Nina , Hill, Martin P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423982 , vital:72113 , xlink:href="https://doi.org/10.1111/eea.12812"
- Description: The discovery that cryptic species are more abundant than previously thought has implications for weed biological control, as there is a risk that cryptic species may be inadvertently released with consequences for the safety of the practice. A cryptic species of a biological control agent released for the control of the invasive alien macrophyte, water hyacinth, Eichhornia crassipes (C. Mart.) Solms. (Pontederiaceae), was recently discovered in South Africa. The two species were considered a single species prior to genetic analysis and interbreeding experiments. The original biological control agent retains the name Eccritotarsus catarinensis (Carvalho) (Heteroptera: Miridae) whereas the new species has been described as Eccritotarsus eichhorniae Henry. In this study, we compared the host specificity, efficacy, and thermal physiologies of the two species. The host specificity of the two species within the Pontederiaceae was very similar and both are safe for release in South Africa. Comparison of the per capita impact of the two species indicated that E. eichhorniae was the more damaging species but this is likely to be influenced by temperature, with E. catarinensis being more effective under lower temperatures and E. eichhorniae being more effective under higher temperatures. Releasing the correct species for the thermal environment of each release site will improve the level of control of water hyacinth in South Africa. This example highlights the need to keep populations of biological control agents from different native range collection localities separate, and to screen for host specificity and efficacy.
- Full Text:
- Date Issued: 2019
- Authors: Paterson, Iain D , Coetzee, Julie A , Weyl, Philip S R , Griffith, Tamzin C , Voogt, Nina , Hill, Martin P
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423982 , vital:72113 , xlink:href="https://doi.org/10.1111/eea.12812"
- Description: The discovery that cryptic species are more abundant than previously thought has implications for weed biological control, as there is a risk that cryptic species may be inadvertently released with consequences for the safety of the practice. A cryptic species of a biological control agent released for the control of the invasive alien macrophyte, water hyacinth, Eichhornia crassipes (C. Mart.) Solms. (Pontederiaceae), was recently discovered in South Africa. The two species were considered a single species prior to genetic analysis and interbreeding experiments. The original biological control agent retains the name Eccritotarsus catarinensis (Carvalho) (Heteroptera: Miridae) whereas the new species has been described as Eccritotarsus eichhorniae Henry. In this study, we compared the host specificity, efficacy, and thermal physiologies of the two species. The host specificity of the two species within the Pontederiaceae was very similar and both are safe for release in South Africa. Comparison of the per capita impact of the two species indicated that E. eichhorniae was the more damaging species but this is likely to be influenced by temperature, with E. catarinensis being more effective under lower temperatures and E. eichhorniae being more effective under higher temperatures. Releasing the correct species for the thermal environment of each release site will improve the level of control of water hyacinth in South Africa. This example highlights the need to keep populations of biological control agents from different native range collection localities separate, and to screen for host specificity and efficacy.
- Full Text:
- Date Issued: 2019
Two in one: cryptic species discovered in biological control agent populations using molecular data and crossbreeding experiments
- Paterson, Iain D, Mangan, Rose, Downie, Douglas A, Coetzee, Julie A, Hill, Martin P, Burke, Ashley M, Downey, Paul O, Henry, Thomas J, Compton, Stephen G
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
- Authors: Paterson, Iain D , Mangan, Rose , Downie, Douglas A , Coetzee, Julie A , Hill, Martin P , Burke, Ashley M , Downey, Paul O , Henry, Thomas J , Compton, Stephen G
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424877 , vital:72191 , xlink:href="https://doi.org/10.1002/ece3.2297"
- Description: There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution.
- Full Text:
- Date Issued: 2016
Assessing the status of biological control as a management tool for suppression of invasive alien plants in South Africa
- Zachariades, Costas, Paterson, Iain D, Strathie, Lorraine W, Hill, Martin P, van Wilgen, Brian W
- Authors: Zachariades, Costas , Paterson, Iain D , Strathie, Lorraine W , Hill, Martin P , van Wilgen, Brian W
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59762 , vital:27646 , https://doi.org/10.4102/abc.v47i2.2142
- Description: Biological control of invasive alien plant (IAP) species is the use of introduced, highly selective natural enemies (usually herbivorous arthropods or pathogens) to control plants. It has been used in 130 countries as a valuable tool for the control of IAP species, with a total of over 550 biological control agents having been released (Winston et al. 2014). The benefits of biological control to natural ecosystems are significant (Van Driesch et al. 2010), with some specific examples of threatened indigenous species being protected by the action of biological control agents (Barton et al. 2007; Meyer, Fourdrigniez & Taputuarai 2011). Detailed analyses of programmes on biological control of IAPs have also clearly indicated that the risks of non-target effects from biological control agents are minimal (Fowler, Syrett & Hill 2000; Funasaki et al. 1988; Moran & Hoffmann 2015; Paynter et al. 2004; Pemberton 2000; Suckling & Sforza 2014). Less than 1% of all the agents released have a negative impact on non-target plant populations, and those that do could have been predicted to do so, and would not be released today (Suckling & Sforza 2014).
- Full Text:
- Date Issued: 2017
- Authors: Zachariades, Costas , Paterson, Iain D , Strathie, Lorraine W , Hill, Martin P , van Wilgen, Brian W
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59762 , vital:27646 , https://doi.org/10.4102/abc.v47i2.2142
- Description: Biological control of invasive alien plant (IAP) species is the use of introduced, highly selective natural enemies (usually herbivorous arthropods or pathogens) to control plants. It has been used in 130 countries as a valuable tool for the control of IAP species, with a total of over 550 biological control agents having been released (Winston et al. 2014). The benefits of biological control to natural ecosystems are significant (Van Driesch et al. 2010), with some specific examples of threatened indigenous species being protected by the action of biological control agents (Barton et al. 2007; Meyer, Fourdrigniez & Taputuarai 2011). Detailed analyses of programmes on biological control of IAPs have also clearly indicated that the risks of non-target effects from biological control agents are minimal (Fowler, Syrett & Hill 2000; Funasaki et al. 1988; Moran & Hoffmann 2015; Paynter et al. 2004; Pemberton 2000; Suckling & Sforza 2014). Less than 1% of all the agents released have a negative impact on non-target plant populations, and those that do could have been predicted to do so, and would not be released today (Suckling & Sforza 2014).
- Full Text:
- Date Issued: 2017
Prioritisation of potential agents for the biological control of the invasive alien weed, Pereskia aculeata (Cactaceae), in South Africa
- Paterson, Iain D, Vitorino, Marcello D, de Cristo, S C, Martin, Grant D, Hill, Martin P
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
Effect of water trophic level on the impact of the water hyacinth moth Niphograpta albiguttalis on Eichhornia crassipes
- Canavan, Kim N, Coetzee, Julie A, Hill, Martin P, Paterson, Iain D
- Authors: Canavan, Kim N , Coetzee, Julie A , Hill, Martin P , Paterson, Iain D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423740 , vital:72090 , xlink:href="https://doi.org/10.2989/16085914.2014.893225"
- Description: Eutrophication contributes to the proliferation of alien invasive weed species such as water hyacinth Eichhornia crassipes. Although the South American moth Niphograpta albiguttalis was released in South Africa in 1990 as a biological control agent against water hyacinth, no post-release evaluations have yet been conducted here. The impact of N. albiguttalis on water hyacinth growth was quantified under low-, medium- and high-nutrient concentrations in a greenhouse experiment. Niphograpta albiguttalis was damaging to water hyacinth in all three nutrient treatments, but significant damage in most plant parameters was found only under high-nutrient treatments. However, E. crassipes plants grown in high-nutrient water were healthier, and presumably had higher fitness, than plants not exposed to herbivory at lower-nutrient levels. Niphograpta albiguttalis is likely to be most damaging to water hyacinth in eutrophic water systems, but the damage will not result in acceptable levels of control because of the plant's high productivity under these conditions. Niphograpta albiguttalis is a suitable agent for controlling water hyacinth infestations in eutrophic water systems, but should be used in combination with other biological control agents and included in an integrated management plan also involving herbicidal control and water quality management.
- Full Text:
- Date Issued: 2014
- Authors: Canavan, Kim N , Coetzee, Julie A , Hill, Martin P , Paterson, Iain D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423740 , vital:72090 , xlink:href="https://doi.org/10.2989/16085914.2014.893225"
- Description: Eutrophication contributes to the proliferation of alien invasive weed species such as water hyacinth Eichhornia crassipes. Although the South American moth Niphograpta albiguttalis was released in South Africa in 1990 as a biological control agent against water hyacinth, no post-release evaluations have yet been conducted here. The impact of N. albiguttalis on water hyacinth growth was quantified under low-, medium- and high-nutrient concentrations in a greenhouse experiment. Niphograpta albiguttalis was damaging to water hyacinth in all three nutrient treatments, but significant damage in most plant parameters was found only under high-nutrient treatments. However, E. crassipes plants grown in high-nutrient water were healthier, and presumably had higher fitness, than plants not exposed to herbivory at lower-nutrient levels. Niphograpta albiguttalis is likely to be most damaging to water hyacinth in eutrophic water systems, but the damage will not result in acceptable levels of control because of the plant's high productivity under these conditions. Niphograpta albiguttalis is a suitable agent for controlling water hyacinth infestations in eutrophic water systems, but should be used in combination with other biological control agents and included in an integrated management plan also involving herbicidal control and water quality management.
- Full Text:
- Date Issued: 2014
The herbivorous arthropods associated with the invasive alien plant, Arundo donax, and the native analogous plant, Phragmites australis, in the Free State Province, South Africa s
- Canavan, Kim N, Paterson, Iain D, Hill, Martin P
- Authors: Canavan, Kim N , Paterson, Iain D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406155 , vital:70243 , xlink:href="https://hdl.handle.net/10520/EJC155690"
- Description: The Enemy Release Hypothesis (ERH) predicts that when plant species are introduced outside their native range there is a release from natural enemies resulting in the plants becoming problematic invasive alien species (Lake and Leishman 2004; Puliafico et al. 2008). The release from natural enemies may benefit alien plants more than simply reducing herbivory because, according to the Evolution of Increased Competitive Ability (EICA) hypothesis, without pressure from herbivores more resources that were previously allocated to defence can be allocated to reproduction (Blossey and Notzold 1995). Alien invasive plants are therefore expected to have simpler herbivore communities with fewer specialist herbivores (Frenzel and Brandl 2003; Heleno et al. 2008; Heger and Jeschke 2014).
- Full Text:
- Date Issued: 2014
- Authors: Canavan, Kim N , Paterson, Iain D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406155 , vital:70243 , xlink:href="https://hdl.handle.net/10520/EJC155690"
- Description: The Enemy Release Hypothesis (ERH) predicts that when plant species are introduced outside their native range there is a release from natural enemies resulting in the plants becoming problematic invasive alien species (Lake and Leishman 2004; Puliafico et al. 2008). The release from natural enemies may benefit alien plants more than simply reducing herbivory because, according to the Evolution of Increased Competitive Ability (EICA) hypothesis, without pressure from herbivores more resources that were previously allocated to defence can be allocated to reproduction (Blossey and Notzold 1995). Alien invasive plants are therefore expected to have simpler herbivore communities with fewer specialist herbivores (Frenzel and Brandl 2003; Heleno et al. 2008; Heger and Jeschke 2014).
- Full Text:
- Date Issued: 2014
A promising biological control agent for the invasive alien plant, Pereskia aculeata Miller (Cactaceae), in South Africa
- Paterson, Iain D, Mdodana, Lumka A, Mpekula, Ongezwa, Mabunda, Bheki D, Hill, Martin P
- Authors: Paterson, Iain D , Mdodana, Lumka A , Mpekula, Ongezwa , Mabunda, Bheki D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416806 , vital:71387 , xlink:href="https://doi.org/10.1080/09583157.2014.919439"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien plant from Central and South America that has become a problematic environmental weed in South Africa. A potential biological control agent, the stem-wilter, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), was collected in southern Brazil and imported into quarantine in South Africa. Field host range data suggested that C. schaffneri has a host range restricted to P. aculeata. No-choice nymph survival tests were then conducted on 27 test plant species in 9 families. Survival to the adult stage was only recorded on P. aculeata and the closely related Pereskia grandifolia Haw. (Cactaceae). Mortality was significantly higher on P. grandifolia with only 3% of the nymphs reaching the adult stage compared with 74% on P. aculeata indicating that P. aculeata is the primary host plant. P. grandifolia is native in South America and is of no agricultural importance in South Africa so any feeding on P. grandifolia in South Africa would have no negative environmental or economic consequences. In other tests, adult survival on P. aculeata [25.8 days (SE ± 3.74)] was significantly longer than on other test plant species [4.3 days (SE ± 0.36)] further confirming the host specificity of the species. Impact studies conducted in quarantine indicated that C. schaffneri is damaging to P. aculeata, significantly reducing the number of leaves and the shoot lengths of plants, even at relatively low insect densities. C. schaffneri is safe for release in South Africa and is likely to be a damaging and effective agent.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Mdodana, Lumka A , Mpekula, Ongezwa , Mabunda, Bheki D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416806 , vital:71387 , xlink:href="https://doi.org/10.1080/09583157.2014.919439"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien plant from Central and South America that has become a problematic environmental weed in South Africa. A potential biological control agent, the stem-wilter, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), was collected in southern Brazil and imported into quarantine in South Africa. Field host range data suggested that C. schaffneri has a host range restricted to P. aculeata. No-choice nymph survival tests were then conducted on 27 test plant species in 9 families. Survival to the adult stage was only recorded on P. aculeata and the closely related Pereskia grandifolia Haw. (Cactaceae). Mortality was significantly higher on P. grandifolia with only 3% of the nymphs reaching the adult stage compared with 74% on P. aculeata indicating that P. aculeata is the primary host plant. P. grandifolia is native in South America and is of no agricultural importance in South Africa so any feeding on P. grandifolia in South Africa would have no negative environmental or economic consequences. In other tests, adult survival on P. aculeata [25.8 days (SE ± 3.74)] was significantly longer than on other test plant species [4.3 days (SE ± 0.36)] further confirming the host specificity of the species. Impact studies conducted in quarantine indicated that C. schaffneri is damaging to P. aculeata, significantly reducing the number of leaves and the shoot lengths of plants, even at relatively low insect densities. C. schaffneri is safe for release in South Africa and is likely to be a damaging and effective agent.
- Full Text:
- Date Issued: 2014
Biological control of cactaceae in South Africa
- Paterson, Iain D, Hoffmann, John H, Klein, Hildegard, Mathenge, C W, Neser, Stephan, Zimmermann, Helmuth G
- Authors: Paterson, Iain D , Hoffmann, John H , Klein, Hildegard , Mathenge, C W , Neser, Stephan , Zimmermann, Helmuth G
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452308 , vital:75119 , https://hdl.handle.net/10520/EJC32918
- Description: This review is a summary of developments that have contributed to the success of several biological control programmes against invasive cactus species (Cactaceae) that have been worked on in South Africa over the last 12 years. Six potential biological control agents have been identified for the control of Pereskia aculeata Mill. and molecular studies have identified the origin of the South African P. aculeata population. Host-specificity testing is now required for the three most promising of these agents. The successful biological control programme against Opuntia stricta (Haw.) Haw. has resulted in a change in management strategies against this weed in the Kruger National Park and the control of O. stricta is now almost entirely reliant on biological control. Taxonomic problems associated with the identification of Cylindropuntia fulgida var. fulgida (Engelm.) F.M.Knuth var. fulgida have been resolved and an appropriate cochineal insect (Hemiptera: Dactylopiidae) biotype has been released, resulting in substantial declines in Cyl. fulgida var. fulgida populations. A long-term monitoring programme has been initiated to evaluate the progress of this new cochineal insect biotype. The Harrisia mealybug, Hypogeococcus pungens Granara de Willink (Hemiptera: Pseudococcidae), which was originally released on Harrisia martinii (Labour.) Britton and Rose has been collected and redistributed onto Cereus jamacaru DC., where it reduces fruit production and leads to the death of both seedlings and large plants. Resolving taxonomic problems to ensure the correct identification of plant species and the most appropriate biological control biotypes have been key issues that have led to the successful control of several cactaceous weed species in South Africa.
- Full Text:
- Date Issued: 2011
- Authors: Paterson, Iain D , Hoffmann, John H , Klein, Hildegard , Mathenge, C W , Neser, Stephan , Zimmermann, Helmuth G
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452308 , vital:75119 , https://hdl.handle.net/10520/EJC32918
- Description: This review is a summary of developments that have contributed to the success of several biological control programmes against invasive cactus species (Cactaceae) that have been worked on in South Africa over the last 12 years. Six potential biological control agents have been identified for the control of Pereskia aculeata Mill. and molecular studies have identified the origin of the South African P. aculeata population. Host-specificity testing is now required for the three most promising of these agents. The successful biological control programme against Opuntia stricta (Haw.) Haw. has resulted in a change in management strategies against this weed in the Kruger National Park and the control of O. stricta is now almost entirely reliant on biological control. Taxonomic problems associated with the identification of Cylindropuntia fulgida var. fulgida (Engelm.) F.M.Knuth var. fulgida have been resolved and an appropriate cochineal insect (Hemiptera: Dactylopiidae) biotype has been released, resulting in substantial declines in Cyl. fulgida var. fulgida populations. A long-term monitoring programme has been initiated to evaluate the progress of this new cochineal insect biotype. The Harrisia mealybug, Hypogeococcus pungens Granara de Willink (Hemiptera: Pseudococcidae), which was originally released on Harrisia martinii (Labour.) Britton and Rose has been collected and redistributed onto Cereus jamacaru DC., where it reduces fruit production and leads to the death of both seedlings and large plants. Resolving taxonomic problems to ensure the correct identification of plant species and the most appropriate biological control biotypes have been key issues that have led to the successful control of several cactaceous weed species in South Africa.
- Full Text:
- Date Issued: 2011
Estimating the age of immature Chrysomya albiceps (Diptera: Calliphoridae), correcting for temperature and geographical latitude
- Richards, Cameron S, Paterson, Iain D, Villet, Martin H
- Authors: Richards, Cameron S , Paterson, Iain D , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442129 , vital:73961 , https://doi.org/10.1007/s00414-007-0201-7
- Description: Developmental curves for Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) were established at 13 different constant temperatures using developmental landmarks and length as measures of age. The thermal summation constants (K) and developmental zeros (D 0) were calculated for five developmental landmarks using the method described by Ikemoto and Takai (Environ Entomol 29:671–682, 2000). Comparison with the K and D 0 values of our findings to those of three previously published studies of C. albiceps suggests that K is directly proportional to geographic latitude, and D 0 is inversely proportional to both K and geographic latitude. Body size and developmental landmarks have a complex relationship because of trade-offs between mortality risk and female fecundity (as measured by body size) at non-optimal temperatures. This relationship can be summarized using superimposed isomorphen and isomegalen diagrams, which can then be used to make forensic estimates of postmortem intervals from larval body lengths. Finally, we recommend that future studies providing data for precise forensic estimates of postmortem intervals should use a relative temporal precision of about 10% of the total duration being measured. For many blowflies, this translates into a sampling interval of approximately every 2 h before hatching, 3 h before first ecdysis and 6 h before second ecdysis.
- Full Text:
- Date Issued: 2008
- Authors: Richards, Cameron S , Paterson, Iain D , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442129 , vital:73961 , https://doi.org/10.1007/s00414-007-0201-7
- Description: Developmental curves for Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) were established at 13 different constant temperatures using developmental landmarks and length as measures of age. The thermal summation constants (K) and developmental zeros (D 0) were calculated for five developmental landmarks using the method described by Ikemoto and Takai (Environ Entomol 29:671–682, 2000). Comparison with the K and D 0 values of our findings to those of three previously published studies of C. albiceps suggests that K is directly proportional to geographic latitude, and D 0 is inversely proportional to both K and geographic latitude. Body size and developmental landmarks have a complex relationship because of trade-offs between mortality risk and female fecundity (as measured by body size) at non-optimal temperatures. This relationship can be summarized using superimposed isomorphen and isomegalen diagrams, which can then be used to make forensic estimates of postmortem intervals from larval body lengths. Finally, we recommend that future studies providing data for precise forensic estimates of postmortem intervals should use a relative temporal precision of about 10% of the total duration being measured. For many blowflies, this translates into a sampling interval of approximately every 2 h before hatching, 3 h before first ecdysis and 6 h before second ecdysis.
- Full Text:
- Date Issued: 2008
Climate modelling suggests a review of the legal status of Brazilian pepper Schinus terebinthifolia in South Africa is required:
- Martin, Grant D, Magengelele, Nwabisa L, Paterson, Iain D, Sutton, Guy F
- Authors: Martin, Grant D , Magengelele, Nwabisa L , Paterson, Iain D , Sutton, Guy F
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148606 , vital:38754 , https://doi.org/10.1016/j.sajb.2020.04.019
- Description: Brazilian pepper (Schinus terebinthifolia) is a tree native to subtropical South America that was introduced into South Africa in the early 1900s as an ornamental plant. The tree has since escaped cultivation and has invaded ruderal and pristine habitats along the eastern coast of South Africa. Brazilian Pepper is also one of the most problematic invasive alien plants in Florida, USA. We modelled the climatically suitable area for this species in South Africa using MaxEnt, with five distinct datasets: incorporating both the native and the invaded range of the species, as well as different backgrounds.
- Full Text:
- Date Issued: 2020
- Authors: Martin, Grant D , Magengelele, Nwabisa L , Paterson, Iain D , Sutton, Guy F
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148606 , vital:38754 , https://doi.org/10.1016/j.sajb.2020.04.019
- Description: Brazilian pepper (Schinus terebinthifolia) is a tree native to subtropical South America that was introduced into South Africa in the early 1900s as an ornamental plant. The tree has since escaped cultivation and has invaded ruderal and pristine habitats along the eastern coast of South Africa. Brazilian Pepper is also one of the most problematic invasive alien plants in Florida, USA. We modelled the climatically suitable area for this species in South Africa using MaxEnt, with five distinct datasets: incorporating both the native and the invaded range of the species, as well as different backgrounds.
- Full Text:
- Date Issued: 2020
Predicting non-target impacts:
- Paynter, Quentin, Paterson, Iain D, Kwong, Raelene M
- Authors: Paynter, Quentin , Paterson, Iain D , Kwong, Raelene M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149982 , vital:38921 , https://doi.org/10.1016/j.cois.2020.02.002
- Description: Biocontrol of invasive alien weeds has produced great benefits, but concerns over undesirable impacts on non-target plants and/or indirect interactions between biocontrol agents and other biota impede the implementation of biocontrol in some countries. Although great strides have been made, continuing uncertainties predicting the realized host range of candidate agents is probably resulting in some being erroneously rejected due to overestimation of risk. Further refinement of host-range testing protocols is therefore desirable. Indirect interactions are inherently harder to predict, and the risk of both direct and indirect non-target impacts may change over time due to biocontrol agents evolving or expanding their range under climate change. Future research directions to better understand the risk of non-target impacts over time are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Paynter, Quentin , Paterson, Iain D , Kwong, Raelene M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149982 , vital:38921 , https://doi.org/10.1016/j.cois.2020.02.002
- Description: Biocontrol of invasive alien weeds has produced great benefits, but concerns over undesirable impacts on non-target plants and/or indirect interactions between biocontrol agents and other biota impede the implementation of biocontrol in some countries. Although great strides have been made, continuing uncertainties predicting the realized host range of candidate agents is probably resulting in some being erroneously rejected due to overestimation of risk. Further refinement of host-range testing protocols is therefore desirable. Indirect interactions are inherently harder to predict, and the risk of both direct and indirect non-target impacts may change over time due to biocontrol agents evolving or expanding their range under climate change. Future research directions to better understand the risk of non-target impacts over time are discussed.
- Full Text:
- Date Issued: 2020
Interactions between two biological control agents and their target weed: a beetle, a bug and a cactus weed
- Mnqeta, Zezethu, Paterson, Iain D
- Authors: Mnqeta, Zezethu , Paterson, Iain D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417475 , vital:71456 , xlink:href="https://doi.org/10.1080/09583157.2019.1631960"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien shrub introduced into South Africa from Brazil. The leaf-feeding beetle, Phenrica guerini Bechyne (Chrysomelidae), was released as a biological control agent in South Africa in 1991 followed by the stem-wilting bug, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), in 2014. This study investigated the interactions between the two agents under laboratory conditions. Potted plants were exposed to one of four treatments: control (no agents), P. guerini only, C. schaffneri only and both species together. Four densities, ranging from 2 to 12 insects per plant were used. Cathorhitha schaffneri alone at low to moderate densities resulted in the same reduction in number of leaves and shoot length as when combine with P. guerini. At the highest density, C. schaffneri reduced the number of leaves significantly more than any treatment. Mortality of P. guerini was significantly higher than C. schaffneri at the highest density when in combination. The antagonistic interaction between P. guerini and C. schaffneri suggests that these agents should not be released together because this would impact negatively on the overall biocontrol programme against P. aculeata. It is recommended that C. schaffneri should be released at sites where P. guerini is not present. Extrapolation of laboratory-based studies into the field is often challenging, so mass-rearing and releases of P. guerini should continue until there is convincing proof that C. schaffneri alone is more effective than P. guerini in the field.
- Full Text:
- Date Issued: 2019
- Authors: Mnqeta, Zezethu , Paterson, Iain D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417475 , vital:71456 , xlink:href="https://doi.org/10.1080/09583157.2019.1631960"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien shrub introduced into South Africa from Brazil. The leaf-feeding beetle, Phenrica guerini Bechyne (Chrysomelidae), was released as a biological control agent in South Africa in 1991 followed by the stem-wilting bug, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), in 2014. This study investigated the interactions between the two agents under laboratory conditions. Potted plants were exposed to one of four treatments: control (no agents), P. guerini only, C. schaffneri only and both species together. Four densities, ranging from 2 to 12 insects per plant were used. Cathorhitha schaffneri alone at low to moderate densities resulted in the same reduction in number of leaves and shoot length as when combine with P. guerini. At the highest density, C. schaffneri reduced the number of leaves significantly more than any treatment. Mortality of P. guerini was significantly higher than C. schaffneri at the highest density when in combination. The antagonistic interaction between P. guerini and C. schaffneri suggests that these agents should not be released together because this would impact negatively on the overall biocontrol programme against P. aculeata. It is recommended that C. schaffneri should be released at sites where P. guerini is not present. Extrapolation of laboratory-based studies into the field is often challenging, so mass-rearing and releases of P. guerini should continue until there is convincing proof that C. schaffneri alone is more effective than P. guerini in the field.
- Full Text:
- Date Issued: 2019