Ant management in Western Cape vineyards.

Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.No abstract available

Acridid ecology in the sugarcane agro-ecosystem in the Zululand region of KwaZulu-Natal, South Africa

CITATION: Bam, A., Addison, P. & Conlong, D. 2020. Acridid ecology in the sugarcane agro-ecosystem in the Zululand region of KwaZulu-Natal, South Africa. Journal of Orthoptera Research, 29(1):9–16, doi:10.3897/jor.29.34626.The original publication is available at https://jor.pensoft.netGrasshoppers and locusts are well known crop and pasture pests throughout the world. Periodically they cause extensive damage to large areas of crops and grazing lands, which often exacerbate food shortage issues in many countries. In South Africa, acridid outbreaks rarely reach economic proportions, but in sugarcane plantations, localized outbreaks of native acridid species have been reported for the last eight years with increasing frequency and intensity in certain areas. This study was undertaken from May 2012 to May 2013 to identify the economically important acridid species in the sugarcane agroecosystem in these outbreak areas, to monitor seasonal activity patterns, to assess sampling methods, and to determine the pest status of the major species through damage ratings. Five acridid species of particular importance were identified: Nomadacris septemfasciata (Serville), Petamella prosternalis (Karny), Ornithacris cyanea (Stoll), Cataloipus zuluensis Sjötedt, and Cyrtacanthacris aeruginosa (Stoll). All species are univoltine. Petamella prosternalis was the most abundant species and exhibited a winter egg diapause, while N. septemfasciata, the second most abundant species, exhibited a winter reproductive diapause. Petamella prosternalis and N. septemfasciata were significantly correlated with the damage-rating index, suggesting that these two species were responsible for most of the feeding damage found on sugarcane. This study, for the first time, identified the acridid species complex causing damage to sugarcane in the Zululand area of KwaZulu-Natal, South Africa, and documented their population characteristics and related damage. These data are important information on which to base sound integrated pest management strategies.SASRINational Research Foundation of South Africahttps://jor.pensoft.net/article/34626/element/8/64680//Publisher's versio

Influence of Maturity and Vineyard Location on Free and Bound Aroma Compounds of Grapes from the Pais Cultivar

Some of the volatile compounds present in grapes give wine is its unique and genuine characteristics. “Terroir” and berry maturity are considered to be the main influences on the expression of these characteristics. This work was undertaken to establish the specific characteristics that define Vitis vinifera cv. País, based on its aromatic profile and free and bound compounds (glycosides), and to assess the effects of location and maturity. Free and bound volatile compounds presented significant differences in the three locations studied. The total amount of free alcohols, acids and ketones depended on the location. During ripening, the amount of aroma precursors increased in all chemical groups in every location studied, and they were found mainly in the skins. With reference to free volatile compounds, it was found that cis-2- hexenol could be a good candidate to assess maturity, and that terpene content seemed to be strongly related to the vineyard location and cultivar conditions. Also, data analysis showed that the free aroma profile seemed to be influenced more by the maturity of the grapes and the bound aroma fraction more by the location

Control options for false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae), in South Africa, with emphasis on the potential use of entomopathogenic nematodes and fungi

False codling moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is an important pest of various fruit crops in South Africa. Current FCM control strategies include the use of chemical insecticides. However, FCM has developed resistance to some of the insecticides, and stringent chemical residue restrictions have been imposed by some foreign markets. Thus, the demand for high-quality fruit has translated into a need for new, efficient and effective integrated pest management (IPM) strategies. One such strategy is the control of the soil-dwelling life stages of FCM, using entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPF). Both of the biocontrol agents concerned have individually been shown to be effective against FCM

Guiding Classical Biological Control of an Invasive Mealybug Using Integrative Taxonomy

The analysed sequences were deposited in Genbank under accession numbers KP771926-KP771972. Mealybug slides are available at the Polytechnic University of Valencia (Valencia, Spain). Parasitoid slides are deposited at Università degli Studi di Napoli Federico II (Portici, Italy).[EN] Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a mealybug of Southern African origin that has recently been introduced into Eastern Spain. It causes severe distortions on young citrus fruits and represents a growing threat to Mediterranean citrus production. So far, biological control has proven unsatisfactory due to the absence of efficient natural enemies in Spain. Hence, the management of this pest currently relies only on chemical control. The introduction of natural enemies of D. aberiae from the native area of the pest represents a sustainable and economically viable alternative to reduce the risks linked to pesticide applications. Since biological control of mealybugs has been traditionally challenged by taxonomic misidentification, an intensive survey of Delottococcus spp. and their associated parasitoids in South Africa was required as a first step towards a classical biological control programme. Combining morphological and molecular characterization (integrative taxonomy) a total of nine mealybug species were identified in this study, including three species of Delottococcus. Different populations of D. aberiae were found on wild olive trees, in citrus orchards and on plants of Chrysanthemoides monilifera, showing intra-specific divergences according to their host plants. Interestingly, the invasive mealybug populations from Spanish orchards clustered together with the population on citrus from Limpopo Province (South Africa), sharing COI haplotypes. This result pointed to an optimum location to collect natural enemies against the invasive mealybug. A total of 14 parasitoid species were recovered from Delottococcus spp. and identified to genus and species level, by integrating morphological and molecular data. A parasitoid belonging to the genus Anagyrus, collected from D. aberiae in citrus orchards in Limpopo, is proposed here as a good biological control agent to be introduced into Spain.This work was supported by the European Union Seventh Framework Programme FP7-IRSES #269196 "IPRABIO" and FP7-IAPP #324475 "COLBICS" and FP7-IRSES #612566 "BIOMODICS". The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.Beltrà Ivars, A.; Addison, P.; Ávalos Masó, JA.; Crochard, D.; García Mari, F.; Guerrieri, E.; Giliomee, JH.... (2015). Guiding Classical Biological Control of an Invasive Mealybug Using Integrative Taxonomy. PLoS ONE. 10(6):1-14. https://doi.org/10.1371/journal.pone.0128685S11410

Sharing the Burden: Empirical Evidence on Corporate Tax Incidence

This study assesses the burden of capital income tax passed onto labor through wage bargaining over economic rents, using estimations based on a unique pseudo-panel data set from Germany for the period 1998 to 2006. Tax return data cover the universe of corporations subject to corporate income tax, and labor market variables reflect the full record of employees covered by Social Security. We find that wage bargaining after a reduction in tax rates does not increase the wage bill if employment effects neglected by previous empirical studies are taken into account. Any increase in the total wage bill by higher wage rates set is equally compensated for by lower levels of employment. If adjustments in employment due to the increased user cost of capital are taken into account, a cut in corporate income taxes by 1 euro increases the wage bill by 0.47 euro. The identification of these effects comes from variation in the firm-specific average corporate tax rate across firms and over time resulting from two substantial tax reforms. The endogeneity of the firmspecific tax rate is controlled for by an instrumental variable approach. The instrument for the observed average tax rate is the counterfactual tax rate that a corporation would have faced in a particular period, had there been no endogenous change of its tax base, constructed using a detailed microsimulation model

Post-harvest control of the grain chinch bug Macchiademus diplopterus (Heteroptera: Lygaiedae) on pears in the Western Cape Province, South Africa

The original publication is available at http://www.actahort.org/books/671/671_76.htmThe grain chinch bug (GCB) M. diplopterus is endemic to the Western Cape and as such is classified as a quarantine pest. The aim of this project was to evaluate post-harvest methods of control to ensure that packed fruit cartons destined for export are free of live GCB adults and acceptable to international quarantine standards. Cold storage trials were carried out at a commercial cold store in Ceres during three years. GCB adults were subjected to controlled atmosphere conditions (treatment) and regular atmosphere conditions (control) for a period of 6 weeks during 2001 and 10 weeks during 2002. The trials during 2001 and 2002 were carried out by packing GCB and pears into cardboard boxes with plastic liners. During 2003 the trial was repeated, but GCB and pears were placed directly into open plastic lug boxes without plastic liners. The results showed that GCB appear to be very well cold-adapted and that at least nine weeks will be required to achieve 100% mortality under controlled atmosphere conditions if pears are packed with plastic liners. A mortality of 100% was never achieved under regular atmosphere conditions for the duration of the trial. If no plastic liners were used, 100% mortality of GCB occurred one week earlier under controlled atmosphere conditions. Sufficient data was generated here to conclude that low temperature in itself was not sufficient to effectively sterilize pears from GCB infestations. The time required to achieve 100% mortality under controlled atmosphere conditions would probably compromise fruit quality or be unacceptably long

Effect of contact pesticides on vine mealybug parasitoids, Anagyrus sp. near pseudococci (Girault) and Coccidoxenoides perminutus (Timberlake) (Hymenoptera: Encyrtidae)

The original publication is available at http://www.sasev.org/.Anagyrus species near pseudococci (Girault) and Coccidoxenoides perminutus (Timberlake) (Hymenoptera: Encyrtidae) are well-known mealybug parasitoids. Both are proven biological control agents of Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) in vineyards. These parasitoids are affected by some pesticides used for the control of ants (Hymenoptera: Formicidae) and P. ficus in vineyards. To establish which of the vineyard pesticides is more toxic to parasitoids, pesticide bioassays were carried in the laboratory using adult and pupal parasitoids. Fipronil and α-cypermethrin caused significant acute toxicity of both parasitoids. Low mortality was recorded for all these pesticides for parasitoids emerging from mummies indicating that the mummy case was an effective barrier to pesticides for parasitoids. Buprofezin, mancozeb and an insecticidal soap were not toxic to parasitoids in both bioassays. Some pesticides have far-reaching negative impacts on parasitoids of orchard and vineyard arthropod pests. A refinement on pest management strategies regarding method and timing of application of pesticides where parasitoids constitute part of the pest management program is essential.Publishers' versio