Entomopathogenic fungi associated with cultivated honeybush, Cyclopia spp., in South Africa and their pathogenicity towards a leafhopper pest, Molopopterus sp.(Hemiptera: Cicadellidae)
- Mushore, Tapiwa G, Coombes, Candice A, Hill, Martin P
- Authors: Mushore, Tapiwa G , Coombes, Candice A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451382 , vital:75045 , http://dx.doi.org/10.17159/2254-8854/2023/a14183
- Description: The southern and eastern parts of the African Fynbos region favour the production of honeybush tea. Honeybush biomass and extracts are used to prepare a beverage both locally and internationally, mainly as herbal tea with health benefits. Honeybush tea is mostly grown organically requiring natural control measures for pests and diseases. The leafhopper, Molopopterus sp., is one of the most important pests of cultivated honeybush in South Africa, as its feeding compromises the quality and quantity of the yield through leaf discolouration and reduction of the photosynthetic area. Local entomopathogenic fungi (EPF) can provide a pool of potential biocontrol agents for this pest. Therefore, a total of 98 soil samples were collected from organically grown honeybush fields and vegetation surrounding the honeybush fields in the Western Cape province of South Africa. Entomopathogenic fungi were isolated using the insect bait method and were characterised using molecular techniques. Twenty fungal isolates of Metarhizium anisopliae and Fusarium oxysporum were recovered from soil samples, of which 70% were from honeybush fields and 30% were from surrounding vegetation.
- Full Text:
- Date Issued: 2023
- Authors: Mushore, Tapiwa G , Coombes, Candice A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451382 , vital:75045 , http://dx.doi.org/10.17159/2254-8854/2023/a14183
- Description: The southern and eastern parts of the African Fynbos region favour the production of honeybush tea. Honeybush biomass and extracts are used to prepare a beverage both locally and internationally, mainly as herbal tea with health benefits. Honeybush tea is mostly grown organically requiring natural control measures for pests and diseases. The leafhopper, Molopopterus sp., is one of the most important pests of cultivated honeybush in South Africa, as its feeding compromises the quality and quantity of the yield through leaf discolouration and reduction of the photosynthetic area. Local entomopathogenic fungi (EPF) can provide a pool of potential biocontrol agents for this pest. Therefore, a total of 98 soil samples were collected from organically grown honeybush fields and vegetation surrounding the honeybush fields in the Western Cape province of South Africa. Entomopathogenic fungi were isolated using the insect bait method and were characterised using molecular techniques. Twenty fungal isolates of Metarhizium anisopliae and Fusarium oxysporum were recovered from soil samples, of which 70% were from honeybush fields and 30% were from surrounding vegetation.
- Full Text:
- Date Issued: 2023
Evaluating the establishment of a new water hyacinth biological control agent in South Africa
- Miller, Benjamin E, Coetzee, Julie A, Hill, Martin P
- Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451399 , vital:75046 , http://dx.doi.org/10.17159/2254-8854/2023/a15613
- Description: Megamelus scutellaris Berg (Hemiptera: Delphacidae) is the most recent of nine biological control agents developed to manage invasive water hyacinth, Pontederia (= Eichhornia) crassipes Mart.(Pontederiaceae), in South Africa. More than a million M. scutellaris have been mass-reared and released since the first introduction of the agent into South Africa in 2013, successfully establishing overwintering populations at 32 sites in seven of the nine provinces. Establishment has also been recorded at seven of these sites through natural dispersal from sites where they had established. Inundative releases, where large numbers of M. scutellaris are released regularly, have resulted in excellent establishment, and caused a significant reduction in water hyacinth cover in areas where, historically, biological control seemed unlikely due to excessive eutrophication. Although M. scutellaris has established well throughout South Africa through classical biological control methods, this study also showed that inundative releases of biological control agents over multiple seasons results in the most effective control of the weed, especially at cool temperate and eutrophic sites.
- Full Text:
- Date Issued: 2023
- Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451399 , vital:75046 , http://dx.doi.org/10.17159/2254-8854/2023/a15613
- Description: Megamelus scutellaris Berg (Hemiptera: Delphacidae) is the most recent of nine biological control agents developed to manage invasive water hyacinth, Pontederia (= Eichhornia) crassipes Mart.(Pontederiaceae), in South Africa. More than a million M. scutellaris have been mass-reared and released since the first introduction of the agent into South Africa in 2013, successfully establishing overwintering populations at 32 sites in seven of the nine provinces. Establishment has also been recorded at seven of these sites through natural dispersal from sites where they had established. Inundative releases, where large numbers of M. scutellaris are released regularly, have resulted in excellent establishment, and caused a significant reduction in water hyacinth cover in areas where, historically, biological control seemed unlikely due to excessive eutrophication. Although M. scutellaris has established well throughout South Africa through classical biological control methods, this study also showed that inundative releases of biological control agents over multiple seasons results in the most effective control of the weed, especially at cool temperate and eutrophic sites.
- Full Text:
- Date Issued: 2023
Biological control of Salvinia molesta in South Africa revisited
- Martin, Grant D, Coetzee, Julie A, Weyl, Philip S R, Parkinson, Matthew C, Hill, Martin P
- Authors: Martin, Grant D , Coetzee, Julie A , Weyl, Philip S R , Parkinson, Matthew C , Hill, Martin P
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103878 , vital:32318 , https://doi.org/10.1016/j.biocontrol.2018.06.011
- Description: The aquatic weed Salvinia molesta D.S. Mitch. (Salviniaceae) was first recorded in South Africa in the early 1900s, and by the 1960s was regarded as one of South Africa’s worst aquatic weeds. Following the release of the weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) in 1985, the weed is now considered under successful biological control. However, the post-release evaluation of this biological control programme has been ad hoc, therefore, to assess the efficacy of the agent, annual quantitative surveys of South African freshwater systems have been undertaken since 2008. Over the last ten years, of the 57 S. molesta sites visited annually in South Africa, the weevil has established at all of them. Eighteen sites are under successful biological control, where the weed no longer poses a threat to the system and 19 are under substantial biological control, where biological control has reduced the impact of the weed. Since 2008, the average percentage weed cover at sites has declined significantly from 51–100% cover to 0–5% cover in 2017 (R2 = 0.78; P < 0.05). Observations of site-specific characteristics suggest that biological control is most effective at small sites and more difficult at larger and shaded sites. Our findings show that S. molesta remains under good biological control in South Africa, however, some sites require intermittent strategic management, such as augmentative releases of C. salviniae.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Grant D , Coetzee, Julie A , Weyl, Philip S R , Parkinson, Matthew C , Hill, Martin P
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103878 , vital:32318 , https://doi.org/10.1016/j.biocontrol.2018.06.011
- Description: The aquatic weed Salvinia molesta D.S. Mitch. (Salviniaceae) was first recorded in South Africa in the early 1900s, and by the 1960s was regarded as one of South Africa’s worst aquatic weeds. Following the release of the weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) in 1985, the weed is now considered under successful biological control. However, the post-release evaluation of this biological control programme has been ad hoc, therefore, to assess the efficacy of the agent, annual quantitative surveys of South African freshwater systems have been undertaken since 2008. Over the last ten years, of the 57 S. molesta sites visited annually in South Africa, the weevil has established at all of them. Eighteen sites are under successful biological control, where the weed no longer poses a threat to the system and 19 are under substantial biological control, where biological control has reduced the impact of the weed. Since 2008, the average percentage weed cover at sites has declined significantly from 51–100% cover to 0–5% cover in 2017 (R2 = 0.78; P < 0.05). Observations of site-specific characteristics suggest that biological control is most effective at small sites and more difficult at larger and shaded sites. Our findings show that S. molesta remains under good biological control in South Africa, however, some sites require intermittent strategic management, such as augmentative releases of C. salviniae.
- Full Text:
- Date Issued: 2018
The abundance of an invasive freshwater snail Tarebia granifera (Lamarck, 1822) in the Nseleni River, South Africa
- Jones, Roy W, Hill, Jaclyn M, Coetzee, Julie A, Hill, Martin P, Avery, T S, Weyl, Olaf L F
- Authors: Jones, Roy W , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P , Avery, T S , Weyl, Olaf L F
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69077 , vital:29382 , https://doi.org/10.2989/16085914.2017.1298984
- Description: The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.
- Full Text: false
- Date Issued: 2017
- Authors: Jones, Roy W , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P , Avery, T S , Weyl, Olaf L F
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69077 , vital:29382 , https://doi.org/10.2989/16085914.2017.1298984
- Description: The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.
- Full Text: false
- Date Issued: 2017
Quantitative post-release evaluation of biological control of floating fern, Salvinia molesta DS Mitchell (Salviniaceae), with Cyrtobagous salviniae Calder and Sands (Coleoptera Curculionidae) on the Senegal River and Senegal River Delta
- Diop Ousseynou, Hill, Martin P
- Authors: Diop Ousseynou , Hill, Martin P
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451467 , vital:75051 , https://hdl.handle.net/10520/EJC32802
- Description: The floating aquatic fern, Salvinia molesta D.S Mitchell (Salviniaceae) was first recorded in Senegal in 1999 and by 2000 it covered an estimated area of 18 000 ha on the Senegal River Left Bank and tributaries (Senegal) and 7840 ha on the Senegal River Right Bank (Mauritania). The weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) was considered the best option for control and some 48 953 weevils were released at 270 sites during 2002. Within one year, weevils had established and were recovered up to 50km from the release sites. At most of the release sites, the S. molesta infestation was reduced from 100 % to less than 5 % within 24 months of release. These results are discussed in the context of the weed's negative impact on aquatic systems.
- Full Text:
- Date Issued: 2009
- Authors: Diop Ousseynou , Hill, Martin P
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451467 , vital:75051 , https://hdl.handle.net/10520/EJC32802
- Description: The floating aquatic fern, Salvinia molesta D.S Mitchell (Salviniaceae) was first recorded in Senegal in 1999 and by 2000 it covered an estimated area of 18 000 ha on the Senegal River Left Bank and tributaries (Senegal) and 7840 ha on the Senegal River Right Bank (Mauritania). The weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) was considered the best option for control and some 48 953 weevils were released at 270 sites during 2002. Within one year, weevils had established and were recovered up to 50km from the release sites. At most of the release sites, the S. molesta infestation was reduced from 100 % to less than 5 % within 24 months of release. These results are discussed in the context of the weed's negative impact on aquatic systems.
- Full Text:
- Date Issued: 2009
Suitability of Metriona elatior (Klug)(Coleoptera: Chrysomelidae: Cassidinae) as a biological control agent for Solanum sisymbriifolium Lam.(Solanaceae).
- Hill, Martin P, Hulley, Patrick E
- Authors: Hill, Martin P , Hulley, Patrick E
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451540 , vital:75058 , https://hdl.handle.net/10520/AJA10213589_195
- Description: A leaf-feeding tortoise beetle, Metriona elatior (Klug), was screened as a biological control agent for the weed Solanum sisymbriifolium Lam. in South Africa. Favourable biological characteristics of M. elatior include a high reproductive capacity, long-lived adults and several generations per year under laboratory conditions. Host range was investigated by larval survival, and host plant choice tests by adults. Larvae were successfully reared on 10 of 11native Solanum species tested, five exotic Solanum species (except S. sisymbriifolium) and on the economically important eggplant, S. melongena L. The adult females selected these native and exotic Solanum species, and eggplant as suitable for oviposition. Based on these results it was decided not to apply for release of this insect.
- Full Text:
- Date Issued: 1996
- Authors: Hill, Martin P , Hulley, Patrick E
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451540 , vital:75058 , https://hdl.handle.net/10520/AJA10213589_195
- Description: A leaf-feeding tortoise beetle, Metriona elatior (Klug), was screened as a biological control agent for the weed Solanum sisymbriifolium Lam. in South Africa. Favourable biological characteristics of M. elatior include a high reproductive capacity, long-lived adults and several generations per year under laboratory conditions. Host range was investigated by larval survival, and host plant choice tests by adults. Larvae were successfully reared on 10 of 11native Solanum species tested, five exotic Solanum species (except S. sisymbriifolium) and on the economically important eggplant, S. melongena L. The adult females selected these native and exotic Solanum species, and eggplant as suitable for oviposition. Based on these results it was decided not to apply for release of this insect.
- Full Text:
- Date Issued: 1996
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