Abstract: Lepidopteran stemborers are key destructive insect pests of cereal crops in sub-Saharan Africa with the indigenous noctuids Busseola fusca (Fuller) and Sesamia calamistis Hampson and the exotic crambid Chilo partellus Swinhoe accounting for ~5-75% of potential cereal crop yield losses. The main larval endoparasitoids comprising, indigenous Cotesia sesamiae and exotic Cotesia flavipes Cameron contribute to a significant extent in managing these economic herbivorous insect pests. How...
Abstract: Plastic adjustments of physiological tolerance to a particular stressor can result in fitness benefits for resistance that might manifest not only in that same environment, but might also be advantageous when faced with alternative environmental stressors, a phenomenon termed cross-tolerance. The nature and magnitude of cross-tolerance responses can provide important insights into the underlying genetic architecture, potential constraints on, or versatility of, an organism’s stre...
Abstract: Issues on environmental soil quality continue to attract much global attention. Domestic wastewater is a potential source of contaminants capable of degrading the soil environment. This study reports the accumulative effects of 21 years (1995 – 2016) of treated wastewater discharge on heavy metal concentration levels in the proximal environment of Palapye wastewater treatment Plant (PWTP), Central Botswana. Soil samples were collected from eight geo-referenced pedons: four situat...
Abstract: Vegetation plays a vital and important role in regulating climate, water balance and energy. This research examines vegetation variability and degradation in semi-arid Palapye, eastern Botswana. These were assessed over an 18 year period (1998 to 2016) using Remote Sensing based Normalized Difference Vegetation Index (NDVI) time series data. NDVI has been widely used as an indicator of vegetation growth because it measures the amount of plant greenness from the spectral responses m...
Abstract: The aim of this thesis was to identify an abundant, easily available, cheap and environmentally friendly waste material(s) in our locality, Botswana, that could be valorized (rejuvenated) by subjecting it to a simple green procedure, then apply as an adsorbent to clean wastewater through the removal or reduction of ions Co, Ni, Zn, Cu, Hg, Cr, Ag, Fe, Pb, Al, As, Cd, Sn, Ti, Mg, F-, Cl-, SO42-, PO43-, NO2-, BrO3-, and NO3- that usually exist in wastewater. After an extensive search...
Abstract: In Botswana crop production has been the most vulnerable component of the agricultural sector due to its heavy reliance on rainfed agriculture. At the same time, the availability of rainfall is uncertain due to natural climatic variability which is worsened by climate change. Already the local farmers have knowledge of the climatic conditions around them, and from time to time, they have been adjusting their farming practices in line with the prevailing climatic conditions. Climate...
Abstract: Delonix regia, an ornamental tree that can tolerate an elevated level of heavy metals, was evaluated for phytoremediation potential in mine tailings with fly ash, compost, and mycorrhiza. A two-factorial experiment was conducted under screen house conditions using mine tailings from Bamangwato Concessions Limited (BCL) Cu-Ni mine. The treatments are mine tailing (MT) without mycorrhiza (MT – AM), MT with mycorrhiza (MT + AM), MT with 10% fly ash (FA) without mycorrhiza (MT + FA �...
Abstract: Droughts pose a significant challenge to water resources, causing several socio-economic consequences. The growing economy requires improved assessments of drought-related impacts in the water sector, particularly under semi-arid environments where its climate is getting drier and warmer. This study proposes a probabilistic model (copula approach) that is intended to contribute to the drought risk assessment by providing an essential information in drought prediction, decision...
Abstract: Citizens owned fuel transport companies in Botswana are startups and are operating at a small to medium scale. Being startups or Small and Medium Enterprises (SMEs), they are faced with similar challenges that confront most new small businesses. The aim of this study was to assess the challenges faced by citizen-owned fuel transport companies in Botswana and their influence on enterprise growth. The role of finance, human resources, industry experience, and government support was e...
Abstract: Global insect pest invasions have dramatically increased over the past decades, posing significant biosecurity threats to natural and managed ecosystems. As such, the mechanisms of spread and rapid establishment of invasive species have been a key issue for agricultural stakeholders. Similarly, while availability of suitable plant hosts is key to establishment, the eco-physiological mechanisms facilitating invasion amongst most invasive species are unclear. The South American ...
Abstract: Human exposure to Naturally Occurring Radioactive Materials (NORMs) and toxic heavy metals has been a concern for the entire history of mankind since they are com monly found in the environment. Their increased levels are a result of anthropogenic activities such as mining. A-cap Resources Ltd, now A-cap Energy Ltd company dis covered that there were large uranium deposits in the underlying rocks of Serule. It was given licensing to start mining in 2016 with a lease of about 144 km...
Abstract: Shooting ranges continue to pose environmental and human health risk due to the accumulation of toxic Pb emanating from munitions. Remediation of Pb pollution at shooting ranges has been carried out through application of various techniques of which chemical stabilization is the most common. In some instances, field chemical stabilization has achieved Pb decontamination of the soils to concentrations below the maximum contaminant limits as set by the United States Environmental Pro...
Abstract: Bacterial diversity is known to be a driver of soil ecosystem services and it is influenced by the natural integrity of the environments. Samples from garden soil, saline soil and sludge-impacted soil were studied to evaluate the influence of soil properties on bacterial abundance and diversity for improved management. Soil samples were collected from 0 to 15 cm depth and analyzed for selected physico-chemical properties using routine labo- ratory procedures. 16S rRNA gene-based me...
Abstract: Commissioned and de-commissioned shooting ranges continue to pose an environmental and human health risk due to the accumulation of toxic Pb emanating from spent munitions. The phytotoxic effects of Pb accumulation in plants include inhibition of root growth and lowering of plant metabolism. The uptake of Pb by plants is directly affected by factors such as plant species and physicochemical properties of the soil. However, scientists and researchers have leveraged on the ability of...
Abstract: Distributed numerical models, considered as optimal tools for groundwater resources management, have always been constrained by availability of spatio-temporal input data. This problem is particularly distinct in arid and semi-arid developing countries, characterized by large spatio-temporal variability of water fluxes but scarce ground-based monitoring networks. That problem can be mitigated by remote sensing (RS) methods, which nowadays are applicable for modelling not only surfa...