Managing legume pests in sub-Saharan Africa: Challenges and prospects for improving food security and nutrition through agro-ecological intensification

Pest management technology has been through a number of advances that have, perhaps, moved away from the mass extermination of pests achieved through the advent of synthetic chemicals in the latter half of the 20th century to more agro-ecologically sensitive innovations that attempt to regulate pest populations by interfering with their breeding, attracting predators or repelling the pests from crops whilst attracting them to other plants. However, pest management is more than technology innovations and must enable integration of technologies in a practical and cost-beneficial manner. This paper summarises existing and cutting edge technologies for pest management in the context of legume production in Africa highlighting where advances can be made to improve pest management at the smallholder level. Challenges and opportunities are highlighted, and priorities for research are recommended that complement agro-ecological intensification (AEI). AEI describes the sustainable increase in agricultural production from the same amount of available land area while reducing the negative environmental impacts of agricultural technology (‘Reaping the Benefits’ – The Royal Society, 2009; Green Food Report - Defra, 2011; ‘Sustainable Intensification‘ - Montpellier Report, 2013). AEI aims to harness knowledge of ecological processes to increase food production and improve livelihoods and challenges global agriculture to achieve a doubling in world food production while sustaining the environment in which we live. Synthetics are relatively cheap and provide proven pest control. They are substantially underutilised in Africa and could lead to significant productivity increases if their usage could be increased to levels found in other regions of the world. Challenges and opportunities to increased uptake are • Monetary cost to small holder farmers – cost-benefit not clear when produce is typically not sold or when market values are marginal • Limited end user knowledge on how to use synthetics leads to excessive use, reduced cost-benefit and subsequent environmental and safety hazards, under-dosing and resistance development, use of wrong pesticide for crop and pest, high poisoning rates to users and consumers • Poor regulation leads to adulteration, dumping, limited availability, repackaging without labelling Pesticidal plants are cheap, generally only requiring labour to collect and process, and fit well within IPM and AEI strategies. Most African farmers are familiar with botanicals, but usage is constrained by a number of factors related to gaps in research and development and how they are regulated. Challenges and opportunities to uptake are • Although generally low-risk, safety data are lacking. • Hundreds of plant species have been evaluated for efficacy, factors influencing reliability of efficacy are unknown, e.g. that influence the production of bioactive constituents (altitude, season, soil type), that effect the amount of bioactive compounds extracted (solubility, volatility) or the duration/level of control to be expected for different pest species. • A high level of knowledge is required to use pesticidal plants (when/where to harvest, how to prepare/extract) although much of this may already be known • Availability of sufficient plants can be limited and/or unreliable due to over-collection, unsustainable collection or competing uses (medicine, fodder, food, fibre) as well as poor propagation properties or habitat conservation • Regulatory frameworks treat pesticidal plants in the same way as synthetics, and high registration costs of existing systems prevent developing products which cannot be protected by patent making it difficult to invest in registration costs • Complex chemistry makes registration of products difficult • Variability in efficacy is a limiting factor but can be managed by selection of effective provenances for propagation Biopesticides are highly appropriate for IPM and AEI of legume crop production. Several products exist that could contribute to improved legume production in Africa. Challenges and opportunities to uptake are • The cost of products generally puts them out of reach of small holder farmers • Shelf life of products is often limited, requiring relatively sophisticated marketing chains to improve delivery of high quality products • Cost-benefits not clear due to input price vs. potential income or gain in food security/nutrition • Research and development is focussed on servicing developed country needs, often advanced technology/knowledge is required to mass produce biopesticides. • Effects often not immediately evident and pest takes days to control leaving farmers uncertain of their benefits Biocontrol organisms are highly appropriate for IPM and AEI of legume crop production. Artificial augmentation of predators and parasitoids can work well, but is generally expensive to produce and works best with high value crops in enclosed environments, such as glasshouses, where it is relatively easier to maintain investment and prevent escape of organisms. Augmentation in small holder legume farming systems is probably not cost-beneficial in the short to medium term in Africa. However improving farming practice to improve ecosystem services of natural biocontrol is feasible. Challenges and opportunities to uptake of natural biocontrol are • More research is required on the alternative crop requirements and optimal environments for predators and parasitoids as it is still not clear how best to optimise predator numbers for key pests or what level of pest control can be achieved • Increasing end user knowledge on how to improve (engineer) environments that increase predation combined and enhance pollinators • Understanding costs and benefits of improved biocontrol, particularly when physical inputs are required (e.g. planting/maintaining trap crops or overwintering crops) • Increasing farmer knowledge on the impact of general farm practices on biocontrol (frequent use of generic synthetic pesticides, field clearing with fire) Semiochemicals are highly appropriate for IPM and AEI of legume crop production. Pheromone traps can be cost-effective for monitoring important pests like army worm or pod borer, particularly if implemented at the community level. The cost-benefits of pheromones to manage pest populations (through mating disruption or removal trapping) is less clear and currently only works for some key pests of high value crops. The use of naturally released semiochemicals through push-pull cropping strategies has been shown to be highly beneficial for reducing key maize pests in smallholder farming. Despite this, evidence of uptake by African farmers has been limited even when heavily promoted through intensive knowledge training programmes. Challenges and opportunities to uptake are • The cost of products generally puts them out of reach of smallholder farmers • Efficacy may be limited • Knowledge to use effectively is high Resistance mechanisms are arguably the most effective method for delivering improved pest management to small holder farmers. Farmers may have to buy seed, but then often don’t need to make any further inputs to receive benefits of lower pest problems. If non-hybrid resistant varieties are developed, farmers can self-propagate the crop for many years. Challenges and opportunities to uptake are • The costs of developing new varieties is coming down through the use of gene marker technologies; however, developing resistant varieties still requires a significant research investment, often supported by the public sector. • Adding resistance often means enhancing the natural production of detrimental compounds with in the plant, which may have effects on consumer health and safety and/or pollinators/ecosystem services. • The cost-benefits may be high for farmers, but if adding in the R&D investment, it is not clear whether overall cost-benefits to society are positive, particularly if insects rapidly adapt to resistance mechanisms requiring further investment in varietal development. • Some of the more rapid methods of resistance breeding, e.g. genetic modification, remain controversial The development of strategies to enhance agro-ecosystem resilience is by definition an integral part of IPM and AEI in legume production. In many cases farmers already employ traditional practices which improve agroecosystem resilience. Frequently, the practices do not require expensive inputs or elaborate technology. Challenges and opportunities to uptake are • The strategies may be multi-facetted and complex with diverse objectives rather than being a more tangible single technology directed at a specific problem. This impinges on issues of training and clarity in what is being offered • Strategies tend to be beneficial to the health of the agro-ecosystem in general (soils, nutrition, water, pollination) but often have limited direct effect on pests • Conflicts may exist between objectives so, for example, use of green manure while having advantages for soil, nutrition and water, can also increase soil pest problems • Perhaps more than other approaches, agro-ecosystem resilience strategies are not ‘one size fits all’, and must be tailored to local conditions, e.g. appropriate intercropping strategies are dependent on the cropping system and culinary context • Some strategies, e.g. incorporation of areas of natural vegetation in the agro-ecosystem landscape, require implementation of wide geographical scales in order to achieve most benefit Agroecological pest management by small holder farmers in Africa requires building substantial understanding of crop-pest-environmental interactions, which requires investment in training by institutions and farmers. This presents certain challenges and opportunities: • Farmer field school approaches are well developed in many parts of Africa and have been successfully used in Asia to develop capacity for agroecological pest management. The experience in Africa has been that only a limited number of farmers invest in building agroecological reasoning into their management, but FFS have been effective in promoting farmer to farmer technology transfer. • Agroecological knowledge based pest management has been more successful in higher value crops, with complex pest problems, and where use of pesticides may be limited by regulation or have limited effectiveness. • Research and validation is required is develop discovery-based learning approaches that will enable farmers to take informed decisions needed for agroecological pest management

The Scanning Probe Microscope

Scanning probe microscopy bas evolved into a powerful tool since its inception in 1982. The scanning probe microscope bas found applications in metrology, spectroscopy, and lithography. We will review the background of the technology, discuss the different types of scanning probe microscopes including the scanning tunneling microscope and the scanning force microscope, and present many of the applications for the instrument

Extracellular adherence protein (Eap) from Staphylococcus aureus does not function as a superantigen

AbstractExtracellular adherence protein (Eap) from Staphylococcus aureus has been reported to have strong anti-inflammatory properties, which make Eap a potential anti-inflammatory agent. However, Eap has also been demonstrated to trigger T-cell activation and to share structural homology with superantigens. In this study, we focused on whether Eap fulfilled the definition criteria for a superantigen. We demonstrate that T-cell activation by Eap is dependent on both major histocompatibility complex class II and intercellular adhesion molecule type 1, that cellular processing is required for Eap to elicit T-cell proliferation, and that the kinetics of proliferation resemble the profile of a conventional antigen and not that of a superantigen

Coffee yield variations and their relations to rainfall events in Nicaragua

In order to predict the impacts of foreseen climate change on coffee production, one first step would be to check the impacts of past climate variations on coffee yields. We developed a survey in coffee zones in Nicaragua to compile the historical registers made by farmers on yields, rainfalls and temperature daily, management and blossoming date, and analyze their relationship to specific climate events. The farmers' perceptions on climate risks and actual damages were also investigated. A simple model was then developed, that links coffee phenology, rainfall effects on flowering and soil water balance. Coffee yield data were obtained from 23 farms, over a span ranging from 6 to 78 years. The Pacific Zone, and the most ancient coffee zone, presented the longest series of yields and rainfalls. Coffee yields are much more variable in this region than in the North Zone (variation coefficient 33% vs. 18%, resp.).Farmers' perceptions agreed with this finding, with much higher risks perceived in the Pacific Zone. Drought and rainfall excess alike were identified as causing the highest risks, temperature variations were not reported, possibly because they are much less easy to perceive than rainfall variations. The blossoming period was perceived, in both regions, as the most sensitive period, to drought as well as to rainfall excess. Drought events are perceived as more frequent. Very long series on blossoming dates and intensities allowed us to build and calibrate a model, based on rainfall and temperature, to estimate the rainfall during blossoming and the resulting yield loss. Rainfall over 40 mm during the blossoming could reduce the yield from 60%. Alternative practices are discussed that could mitigate the risks identified in the risk-prone Pacific zone. (Résumé d'auteur

High modulation bandwidth of semipolar (11–22) InGaN/GaN LEDs with long wavelength emission

Visible light communication requires III-nitride LEDs with a high modulation bandwidth but have c-plane limitations. General illumination requires green/yellow III-nitride LEDs with high optical efficiency that are difficult to achieve on c-plane substrates. Micro-LEDs with a low efficiency are used to obtain a high modulation bandwidth. This paper demonstrates a record modulation bandwidth of 540 MHz for our semipolar green LEDs with a broad area. Semipolar yellow and amber LEDs with modulation bandwidths of 350 and 140 MHz, respectively, have also been reported, and are the longest wavelength III-nitride LEDs. These results agree with differential carrier lifetime measurements

On non-QRT Mappings of the Plane

We construct 9-parameter and 13-parameter dynamical systems of the plane which map bi-quadratic curves to other bi-quadratic curves and return to the original curve after two iterations. These generalize the QRT maps which map each such curve to itself. The new families of maps include those that were found as reductions of integrable lattices

Spouses, Children, and the Pursuit of a Doctorate: Real or Perceived Barriers for Women in Academia

A group of six women, each of them working full-time while pursuing a doctoral degree, began meeting every other week in the fall of 2017. Their backgrounds were unique, and their programs varied, but their goal was the same: to complete their dissertations. Along the way, these women supported each other through writing challenges, committee woes, and balancing the demands of work, life, and the dissertation writing process. A proven model for success, the interdisciplinary writing group these women formed was based on a few basic principles: respect and positive regard for each other’s work, trust that the frustrations shared during meetings were kept confidential, and accountability to each other for the writing goals they set each week. Experts from campus spoke with the group about topics such as: authorship guidelines, research resources, turning the dissertation into publication, life after graduation, and technology tools. The goal of this Ignite Session is to unpack the barriers that may be unique to women and discuss potential strategies for supporting women during these challenges. These personal, vulnerable conversations are timely and significant because more and more women are in pursuit of a doctoral degree. In 2015, 46% of all U.S. doctorates were awarded to women (National Science Foundation). Leonard (2001) offers that women, more so than their male counterparts, face a balancing act between family and scholarship commitments. Moreover, Brown and Watson (2010) report that women tend to time their pursuit of a doctoral degree based upon domestic demands. Wall (2008) adds that for female doctoral students, juggling the demands of professional scholarship and personal life often requires them to make choices between the head and heart. This emotional struggle can feed into self-doubt and bruise self-efficacy for some women, which may slow or entirely halt their progress through a doctoral program. Research culture tends to be deeply founded on objectivity and autonomy by overlooking emotions (Johnson, Lee, & Green, 2000), but channeling emotions via a support group may be a successful strategy for many women. According to Mewburn (2011), many women actively find or form supportive groups where they can engage in honest dialogue to minimize emotional dissonance and share personal feelings and emotions. Historically, dissertation writing has been viewed as an independent venture; often one without external guidance and support. The notion of writing groups as they pertain to the dissertation stage have only recently been recognized as an acceptable support mechanism. Maher, Fallucca, & Mulhern Halasz, (2013) contend that dissertation writing groups can result in the development of a vibrant, intellectual community where commitment to degree completion and scholarly productivity soar. This implication is echoed by the session presenters. Support groups such as the one described by the presenters serve to hold participants accountable to writing outcomes; but potentially more important, a supportive group can dually function as a safe space for doctoral students to find support through the more sensitive challenges of writing the dissertation. To achieve the objectives of the session, presenters will begin by engaging attendees in a discussion of the unique challenges women who are pursuing an advanced degree face. Secondly, group facilitators will focus conversation on the construction and success of the writing group represented and solicit success stories from other attendees with similar approaches. Last, specific strategies from the writing group experience and from the collective experiences of attendees will be cultivated in order to deepen understanding of approaches that each attendee can bring back to his or her campus community for action. It is the ultimate goal of the presenters to validate the fears and concerns commonly shared by women in academia who aspire to develop through formal educational opportunities or through professional development activities and to equip them with multiple strategies for success as individuals and as members of a campus community. This equipment is imperative for faculty affairs officers, faculty developers, and other stakeholders at major medical centers because the success of our female faculty and staff members may well depend on proven, achievable strategies for supporting them through the juggling act they perceive as a significant barrier to achievement

Fairtrade Coffee A study to assess the impact of Fairtrade for coffee smallholders and producer organisations in Indonesia, Mexico, Peru, and Tanzania

This report presents the findings of a major evaluation commissioned by Fairtrade International. This evaluation aims to assess the impact of Fairtrade for coffee smallholders and their organisations to contribute to the evidence base on Fairtrade’s impact to date and to inform Fairtrade on the potential to improve its impact in the future. Millions of smallholder farmer households around the world rely upon coffee for their livelihoods, and the challenges they face are numerous and growing. Fairtrade supports around 812,500 coffee-producing smallholder farmers in 445 producer organisations in 30 countries. In 2013-14 Fairtrade coffee producers reported selling 150,800 MT of coffee on Fairtrade terms. Producer organisations (POs) in four countries, Peru, Mexico, Tanzania, and Indonesia, were selected as cases by the research team to capture the range and depth of the Fairtrade experience. The evaluation covered two Fairtrade producer organisations in each country. Counterfactual comparisons are included in each case – either with a comparison producer organisation or with individual independent farmers cultivating coffee in the same area, but who are not part of Fairtrade certification. The evaluation used the recently developed and published ‘Fairtrade International Theory of Change’ to examine Fairtrade impact. Data was collected along the impact chain to understand how far Fairtrade’s interventions have led to intended outputs and impacts, and to identify other influencing factors. The team developed a research protocol to support comparisons between countries, and used mixed methods to carry out the research

Direct epitaxial approach to achieve a monolithic on-chip integration of a HEMT and a single micro-LED with a high-modulation bandwidth

Visible light communications (VLC) require III-nitride visible micro-light-emitting diodes (μLEDs) with a high-modulation bandwidth. Such μLEDs need to be driven at a high injection current density on a kA/cm2 scale, which is about 2 orders of magnitude higher than those for normal visible LED operation. μLEDs are traditionally fabricated by dry-etching techniques where dry-etching-induced damages are unavoidable, leading to both a substantial reduction in performance and a great challenge to viability at a high injection current density. Furthermore, conventional biasing (which is simply applied across a p–n junction) is good enough for normal LED operation but generates a great challenge for a single μLED, which needs to be modulated at a high injection current density and at a high frequency. In this work, we have proposed a concept for an epitaxial integration and then demonstrated a completely different method that allows us to achieve an epitaxial integration of a single μLED with a diameter of 20 μm and an AlGaN/GaN high-electron-mobility transistor (HEMT), where the emission from a single μLED is modulated by tuning the gate voltage of its HEMT. Furthermore, such a direct epitaxial approach has entirely eliminated any dry-etching-induced damages. As a result, we have demonstrated an epitaxial integration of monolithic on-chip μLED-HEMT with a record modulation bandwidth of 1.2 GHz on industry-compatible c-plane substrates