Parasitoids associated with the diamondback moth, Plutella xylostella (L.), in the Eastern Cape, South Africa
- Authors: Smith, Tamara J , Villet, Martin H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , conference
- Identifier: http://hdl.handle.net/10962/442795 , vital:74034 , ISBN , https://www.cabidigitallibrary.org/doi/full/10.5555/20093098381
- Description: Seasonal fluctuations of diamondback moth and its hymenopteran parasitoids were recorded weekly from April 1997 to November 1999 at four cabbage sites in the Grahamstown area of the Eastern Cape, South Africa. Two sites were commercial farms with active spraying programmes; the others were unsprayed. Infestation levels were highest during spring (September to November) and autumn (March to May), where 100% infestation of plants was reached at times. The highest infestation was found during the spring months, where 12 larvae/plant were found at the unsprayed sites and between 6 and 10 larvae at the sprayed sites. At the unsprayed sites abundance of diamondback moth larvae and parasitoids was high during 1997, but much lower during 1998 and 1999, indicating possible control by the parasitoids. Nine species of parasitoid were recorded from diamondback moth during this period and four (Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae), Diadegma mollipla (Holmgren) (Hymenoptera: Ichneumonidae), Diadromus collaris Gravenhorst (Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae)) showed potential as biological control agents. The highest rate of parasitism was found from mid-autumn to the beginning of winter (April to June) and from mid-spring to the beginning of summer (October to December). Percent parasitism varied throughout the year, ranging between 10% and 80%. Parasitism of 100% was observed when moth numbers were low. Different species of parasitoids were found to be dominant at different times of the year.
- Full Text:
- Date Issued: 2004
Description of adult and larva of Ichnestoma pringlei n. sp. (Coleoptera: Scarabaeidae Cetoniinae), with notes on its biology and ecology
- Authors: Perissinotto, Renzo , Smith, Tamara J , Stobbia, P
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453815 , vital:75289 , https://doi.org/10.1080/03946975.1999.10539390
- Description: There are at present 10 described species in the primitive genus Ichnestoma Gory and Percheron 1833. These are all phylogenetic and geographic relicts of high evolutionary and conservation interest. The discovery of a new species, I. pringlei n. sp., and the first description of a larva (third instar) of this genus are reported here. New information is also presented on their life-cycle and on the dependence of their activities on rainfall patterns, particularly in the semi-arid region of the Karoo. In this region, larvae seem to take 2 years to complete growth and metamorphosis since they feed only after major rainfall events, while remaining inactive and deep underground during dry periods. Adults emerge from their cocoons only after summer rains of at least 15 mm. They lack functional mouth parts and are unable to feed. Their life span is only 3–5 days. Because females are completely flightless and unable to disperse, species of the genus are extremely vulnerable to environmental degradation. It seems likely that they may play a key role in the decomposition of dead plant matter, especially in dry and clay-rich soils where other primary decomposers are scarce.
- Full Text:
- Date Issued: 1999
The larva of Rhinocoeta sanguinipes (Gory and Percheron 1833) (Coleoptera Scarabaeidae) description and phylogenetic inferences
- Authors: Smith, Tamara J , Perissinotto, Renzo , Villet, Martin H
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453942 , vital:75299 , https://doi.org/10.1080/03946975.1998.10539365
- Description: The genus Rhinocoeta Burmeister 1842 is unusual among cetoniines, as adults do not feed on flowers or fruits. The biology and ecology of the genus are still completely unknown, and only for three of the six species representing the group have adults of both sexes been described. No information is available for the larval stages of any of the species. Here, we present the first discription of the third instar larvae of one of the species, Rhinocoeta sanguinipes (Gory and Percheron 1833). Cladistic analysis of larval characters confirms the primitive phylogenetic position of this species relative to a small sample of other South African cetoniines, and supports the hypothesis that the genus might belong in the subtribe Xiphoscelidina rather than the Cetoniina, thereby constituting part of a relict lineage derived directly from the most primitive Cetoniinae.
- Full Text:
- Date Issued: 1998
Description and identification of white grubs (Coleoptera: Scarabaeidae) attacking pineapple crops in South Africa
- Authors: Smith, Tamara J , Petty, G , Villet, Martin H
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6853 , http://hdl.handle.net/10962/d1011134
- Description: Larvae of five species of scarabaeid beetles, Asthenopholis subfasciata Blanchard, Trochalus politus Moser, Macrophylla ciliata Herbst, Congela valida Peringuey and Adoretus ictericus Burmeister, and adults of a sixth species, Heteronychus arator (Fabricius), cause considerable economic damage to the root systems of pineapple plants. The biologies of the species differ, making reliable identification essential. Since no convenient method is available to identify them, both field and laboratory keys are provided for the identification of third instar larvae of the six species, and detailed, illustrated descriptions for confirming their identifications
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- Date Issued: 1995