Agathis bishopi, a larval parasitoid of false codling moth Thaumatotibia leucotreta: laboratory rearing and effect of adult food on parasitism and longevity
- Zimba, Kennedy J, Moore, Sean D, Heshula, Lelethu U P, Hill, Martin P
- Authors: Zimba, Kennedy J , Moore, Sean D , Heshula, Lelethu U P , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406985 , vital:70328 , xlink:href="https://hdl.handle.net/10520/EJC185849"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae) is a koinobiont larval endoparasitoid of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of economic importance on citrus in South Africa. In the field Agathis bishopi was found to parasitise up to 34 % of FCM larvae in fruit, reflecting reasonable biocontrol potential. Improving the rearing of A. bishopi would therefore complement the existing biocontrol strategies for FCM. In several parasitic wasps, sugar concentration and feeding duration has been shown to influence parasitism and longevity. However, their effect on parasitism and longevity of A. bishopi is unknown. In the present study a rearing protocol for A. bishopi is described, including evaluation of the effects of honey concentration on parasitoid longevity. On average, 18.2%of FCM larvae in rearing containers were parasitised under the rearing protocol described. Cotton wool, instead of paper towelling, as honey carrier for feeding parasitoids in rearing containers significantly increased parasitism and yield of offspring. Furthermore, longevity significantly increased with higher concentrations of honey. Maximum lifespan duration for male and female parasitoids was achieved when parasitoids were fed on 36 % (w/v) honey. Results from this study indicate that A. bishopi requires a sufficient concentration of sugar, coupled with frequent and prolonged feeding on a cotton wool substrate, in order to achieve maximum parasitism and longevity. Such information provides a basis for optimising mass-rearing and longevity of A. bishopi and parasitism of FCM in orchards.
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy J , Moore, Sean D , Heshula, Lelethu U P , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406985 , vital:70328 , xlink:href="https://hdl.handle.net/10520/EJC185849"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae) is a koinobiont larval endoparasitoid of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of economic importance on citrus in South Africa. In the field Agathis bishopi was found to parasitise up to 34 % of FCM larvae in fruit, reflecting reasonable biocontrol potential. Improving the rearing of A. bishopi would therefore complement the existing biocontrol strategies for FCM. In several parasitic wasps, sugar concentration and feeding duration has been shown to influence parasitism and longevity. However, their effect on parasitism and longevity of A. bishopi is unknown. In the present study a rearing protocol for A. bishopi is described, including evaluation of the effects of honey concentration on parasitoid longevity. On average, 18.2%of FCM larvae in rearing containers were parasitised under the rearing protocol described. Cotton wool, instead of paper towelling, as honey carrier for feeding parasitoids in rearing containers significantly increased parasitism and yield of offspring. Furthermore, longevity significantly increased with higher concentrations of honey. Maximum lifespan duration for male and female parasitoids was achieved when parasitoids were fed on 36 % (w/v) honey. Results from this study indicate that A. bishopi requires a sufficient concentration of sugar, coupled with frequent and prolonged feeding on a cotton wool substrate, in order to achieve maximum parasitism and longevity. Such information provides a basis for optimising mass-rearing and longevity of A. bishopi and parasitism of FCM in orchards.
- Full Text:
- Date Issued: 2015
Beauveria and Metarhizium against false codling moth (Lepidoptera: Tortricidae): a step towards selecting isolates for potential development of a mycoinsecticide
- Coombes, Candice A, Hill, Martin P, Moore, Sean D, Dames, Joanna F, Fullard, T
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
Book Review Growing the next generation of researchers: A handbook for emerging researchers and their mentors, Holness, L
- Motshoane, Puleng, Muthama, Evelyn, McKenna, Sioux
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
DNA-based identification of Lepidoptera associated with citrus in South Africa
- Marsberg, Tamryn, Hill, Martin P, Moore, Sean D, Timm, Alicia E
- Authors: Marsberg, Tamryn , Hill, Martin P , Moore, Sean D , Timm, Alicia E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405782 , vital:70205 , xlink:href="https://hdl.handle.net/10520/EJC167513"
- Description: A number of insects, primarily Lepidoptera, cause damage to citrus in South Africa. A major limitation to the management and control of these pests is their correct identification. The aim of this study was to develop a database of gene sequences to aid in the identification of these Lepidoptera. Multiple specimens of 12 species were sequenced for the ~650 bp of the cytochrome oxidase I gene. These sequence data were supplemented and validated using sequences available in public databases. Results showed that each species could be unambiguously identified, and neighbour-joining analysis based on K2P distances formed highly supported, distinct clusters for each species, i.e. the maximum intraspecific genetic distance was less than that of the minimum interspecific genetic distances. Thus, this data set provides a molecular means to successfully identify the most important Lepidoptera associated with citrus in South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Marsberg, Tamryn , Hill, Martin P , Moore, Sean D , Timm, Alicia E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405782 , vital:70205 , xlink:href="https://hdl.handle.net/10520/EJC167513"
- Description: A number of insects, primarily Lepidoptera, cause damage to citrus in South Africa. A major limitation to the management and control of these pests is their correct identification. The aim of this study was to develop a database of gene sequences to aid in the identification of these Lepidoptera. Multiple specimens of 12 species were sequenced for the ~650 bp of the cytochrome oxidase I gene. These sequence data were supplemented and validated using sequences available in public databases. Results showed that each species could be unambiguously identified, and neighbour-joining analysis based on K2P distances formed highly supported, distinct clusters for each species, i.e. the maximum intraspecific genetic distance was less than that of the minimum interspecific genetic distances. Thus, this data set provides a molecular means to successfully identify the most important Lepidoptera associated with citrus in South Africa.
- Full Text:
- Date Issued: 2015
Host searching and oviposition behaviour of Agathis bishopi (Hymenoptera: Braconidae), a larval parasitoid of false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae): a potential proxy indicator for fruit infestation
- Zimba, Kennedy J, Heshula, Lelethu U P, Moore, Sean D, Hill, Martin P
- Authors: Zimba, Kennedy J , Heshula, Lelethu U P , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy J , Heshula, Lelethu U P , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
- Date Issued: 2015
The women of Willowvale-crafting livelihoods from the wild date palm
- Mjoli, Nwabisa, Shackleton, Charlie M
- Authors: Mjoli, Nwabisa , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182322 , vital:43820 , xlink:href="https://hdl.handle.net/10520/EJC185235"
- Description: The Wild Coast of the Eastern Cape is renowned for its cultural landscapes, stunning scenery and remarkable biodiversity. It is also one of the least developed regions of South Africa, which underpins the small productive base and limited economic opportunities for the hundreds of rural communities scattered along the hilltops. It is not surprising therefore, that many inhabitants make extensive use of natural resources, such as firewood, reed mats, medicinal plants and wild vegetables, in their daily lives, as well as for sources of income when the opportunity arises.
- Full Text:
- Date Issued: 2015
- Authors: Mjoli, Nwabisa , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182322 , vital:43820 , xlink:href="https://hdl.handle.net/10520/EJC185235"
- Description: The Wild Coast of the Eastern Cape is renowned for its cultural landscapes, stunning scenery and remarkable biodiversity. It is also one of the least developed regions of South Africa, which underpins the small productive base and limited economic opportunities for the hundreds of rural communities scattered along the hilltops. It is not surprising therefore, that many inhabitants make extensive use of natural resources, such as firewood, reed mats, medicinal plants and wild vegetables, in their daily lives, as well as for sources of income when the opportunity arises.
- Full Text:
- Date Issued: 2015
Trophic relationships of hake (Merluccius capensis and M. paradoxus) and sharks (Centrophorus squamosus, Deania calcea and D. profundorum) in the Northern (Namibia) Benguela Current region
- Iitembu, J A, Richoux, Nicole B
- Authors: Iitembu, J A , Richoux, Nicole B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457418 , vital:75636 , xlink:href="https://hdl.handle.net/10520/EJC183122"
- Description: The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (15N and 13C) of their muscle tissues. The sharks were more enriched in 15N than the hake, an indication of the apex predator status of sharks. Among the sharks considered, C. squamosus occupied the highest trophic level and fed primarily on benthic prey. The two species of shark from the genus Deania were not different based on 15N or 13C, so they had similar diets. The 13C signatures indicated that M. capensis and sharks fed on prey derived from similar basal resources. However, there was a significant difference in 13C between M. paradoxus and all other species examined, suggesting that they occupied different feeding niches. Isotope-based populationmetrics showed narrower trophic ranges in sharks than M. capensis. Carbon and nitrogen ranges indicated that hake fed on a more diverse pool of carbon sources and had generally more enhanced trophic diversity in their feeding patterns than sharks. Among the species considered, C. squamosus occupied a unique isotopic space. Our results supported the hypothesis there are trophic overlaps among these species, but some interesting differentiation was revealed.
- Full Text:
- Date Issued: 2015
- Authors: Iitembu, J A , Richoux, Nicole B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457418 , vital:75636 , xlink:href="https://hdl.handle.net/10520/EJC183122"
- Description: The trophic relationships of two hake species (Merluccius capensis and M. paradoxus) and three shark species (Centrophorus squamosus, Deania calcea and D. profundorum) were investigated using nitrogen and carbon stable isotope signatures (15N and 13C) of their muscle tissues. The sharks were more enriched in 15N than the hake, an indication of the apex predator status of sharks. Among the sharks considered, C. squamosus occupied the highest trophic level and fed primarily on benthic prey. The two species of shark from the genus Deania were not different based on 15N or 13C, so they had similar diets. The 13C signatures indicated that M. capensis and sharks fed on prey derived from similar basal resources. However, there was a significant difference in 13C between M. paradoxus and all other species examined, suggesting that they occupied different feeding niches. Isotope-based populationmetrics showed narrower trophic ranges in sharks than M. capensis. Carbon and nitrogen ranges indicated that hake fed on a more diverse pool of carbon sources and had generally more enhanced trophic diversity in their feeding patterns than sharks. Among the species considered, C. squamosus occupied a unique isotopic space. Our results supported the hypothesis there are trophic overlaps among these species, but some interesting differentiation was revealed.
- Full Text:
- Date Issued: 2015
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