Moisture source and diet affect development and reproduction of Orius thripoborus and Orius naivashae, two predatory anthocorids from southern Africa

The effect of moisture source and diet on the development and reproduction of the pirate bugs, Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae) was examined in the laboratory. Both species had been collected in and around sugarcane fields in South Africa. Supplementing eggs of the flour moth Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) with a green bean pod as a moisture source yielded better nymphal survival and faster development, as compared with free water encapsulated in Parafilm, suggesting that the predators may extract extra nutrients from the bean pod. The impact of two factitious foods and moist honey bee pollen on developmental and reproductive parameters of both predators was also investigated. The overall performance of both Orius species on E. kuehniella eggs and cysts of brine shrimp, Artemia franciscana Kellogg (Crustacea: Artemiidae) was better than on pollen. Nonetheless, a pollen diet alone allowed 66 and 78% of the nymphs of O. thripoborus and O. naivashae, respectively, to reach adulthood. Overall, developmental and reproductive performance of O. thripoborus on the tested diets was superior to that of O. naivashae. The implications of these findings for the mass production of these predators and their potential role in biological control programs in southern Africa are discussed

Exploring the role of sugarcane in small-scale farmers’ livelihoods in the Noodsberg Area, Kwazulu-Natal, South Africa

Participatory, mixed-methods research was conducted to study the role of sugarcane in small-scale sugarcane farmers’ livelihoods in the Noodsberg area, KwaZulu-Natal. Thirty-five farmers were visited at their homes and data was collected through semi-structured interviews, participatory sketch mapping, matrix scoring activities and informal field-based discussions. Results indicated that sugarcane was a key livelihood resource providing employment and income, and it generated more income than any other single agricultural enterprise. It was considered the most important crop in most households, even though it was grown within a diverse agricultural system including maize, beans, taro (amadumbe) and potatoes. Considering the important role of sugarcane as a cash crop in farmers’ livelihoods, further development of land to sugarcane in the Noodsberg area will continue to reduce poverty and improve the livelihoods of farmers.Keywords: farming systems, food security, poverty, rural development, small-scale growers, sugarcane

Exact results in planar N=1 superconformal Yang-Mills theory

In the \beta-deformed N=4 supersymmetric SU(N) Yang-Mills theory we study the class of operators O_J = Tr(\Phi_i^J \Phi_k), i\neq k and compute their exact anomalous dimensions for N,J\to\infty. This leads to a prediction for the masses of the corresponding states in the dual string theory sector. We test the exact formula perturbatively up to two loops. The consistency of the perturbative calculation with the exact result indicates that in the planar limit the one--loop condition g^2=h\bar{h} for superconformal invariance is indeed sufficient to insure the {\em exact} superconformal invariance of the theory. We present a direct proof of this point in perturbation theory. The O_J sector of this theory shares many similarities with the BMN sector of the N=4 theory in the large R--charge limit.Comment: LaTex, 14 pages, 3 figures; v2: minor corrections and one reference adde

On Non-renormalization and OPE in Superconformal Field Theories

The OPE of two N=2 R-symmetry current (short) multiplets is determined by the possible superspace three-point functions that two such multiplets can form with a third, a priori long multiplet. We show that the shortness conditions on the former put strong restrictions on the quantum numbers of the latter. In particular, no anomalous dimension is allowed unless the third supermultiplet is an R-symmetry singlet. This phenomenon should explain many known non-renormalization properties of correlation functions, including the one of four stress-tensor multiplets in N=4 SYM_4.Comment: minor corrections, references change

Biological control of indigenous African stemborers: what do we know

Using examples from surveys to collect natural enemies of the indigenous African sugarcane borer Eldana saccharina Walker throughout Africa, insight is given into what factors should be investigated should biological control of other indigenous African stemborers be considered. Indigenous host plant range, parts of indigenous and crop hosts attacked, types of natural enemies found in these different niches and natural enemy attack strategies are all important factors to consider when planning redistribution of indigenous natural enemies from one part of Africa to another. This knowledge is important when choosing the correct natural enemy for mass rearing and release into the affected crop, and can be used to manage the crop habitat, using the indigenous tritrophic systems identified, to increase crop diversity and thus effectiveness of indigenous natural enemies. RÉSUMÉ En se basant sur des exemples d'enquêtes destinées à récolter les ennemis naturels du foreur indigène africain de la canne à sucre Eldana saccharina Walker en Afrique, cet article donne un aperçu des facteurs susceptibles d'être étudiés pour contrôler biologiquement les autres foreurs de tiges indigènes africains. La gamme des plantes hôtes indigènes, les parties attaquées des hôtes indigènes et cultivés, les types d'ennemis naturels trouvés dans ces différentes niches et les stratégies d'attaque des ennemis naturels sont tous des facteurs importants à considérer quand on projette de déplacer des ennemis naturels indigènes d'une région d'Afrique à une autre. Cette connaissance est importante lorsque l'on veut choisir l'ennemi naturel adapté pour la production de masse et pour le lâcher dans la culture affectée; elle peut également être utilisée pour gérer lhabitat de la culture, en utilisant le système tritrophique indigène identifié, afin d'accroître sa diversité et ainsi lefficacité des ennemis naturels indigènes

Combating sugarcane pests in South Africa: from Researching Biotic Interactions to Bio-Intensive Integrated Pest Management in the field

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