Environmental & Physical Sciences

Environmental & Physical Sciences Research Papers/Topics

Generation and composition of municipal solid waste: case study, extension 7, Palapye, Botswana

Abstract: The rapid population growth and industrialisation has contributed to the production of large quantities of solid wastes that should be managed properly. This study was conducted to investigate the generation and composition of solid wastes at different income levels during weekdays and weekends in a particular zone in Palapye municipality (Extension 7), Botswana. The study was conducted through sampling of wastes at source and analysis at the laboratory. In increasing order, the ge...

Waste valorisation opportunities for bush encroacher biomass in savannah ecosystems: a comparative case analysis of Botswana and Namibia

Abstract: Bush encroachment of savannah ecosystems in countries like Botswana and Namibia has been identified as a major problem threatening biodiversity, grazing land productivity and the generation of groundwater. Incidentally, the same problem presents a huge biomass energy resource opportunity which can be exploited through various technologies. This paper defines the scope of the problem in Botswana, comparing with the well documented and partly proven case of encroacher bush waste valo...

An overview of plastic waste generation and management in food packaging industries

Abstract: Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. This has led to unprecedented amounts of mixed types of plastic waste entering the environment unmanaged. Packaging plastics account for half of the global total plastic waste. This paper seeks to give an overview of the use, disposal, and regulation of food packaging plastics. Demand for food packaging is on the rise as a result of increasing global demand for food due to popula...

Hydroclimate changes in eastern Africa over the past 200,000 years may have influenced early human dispersal

Abstract: Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate change, both associated temporally and regionally with a specific type of human behavior. The first is a long-term trend towards greater ar...

Production of activated carbon from poultry feathers for waste water treatment

Abstract: Contamination of water bodies by heavy metal ions is a challenge many developing nations like Zimbabwe face, with negative environmental and socio-economic repercussions. Treating affected bodies usually requires a costly consignment of chemicals and activated carbon. This research investigates the possible use of an abundant waste resource – poultry feathers – to make activated carbon for heavy metal ion removal. Poultry consumption in this nation generates more than five mill...

Household solid waste generation and composition: a case study in Palapye, Botswana

Abstract: The purpose of this case study was to conduct a case study in the generation rate, composition, and characterise solid wastes from low, middle and high income households during weekdays and weekends in Palapye, Botswana. The study was conducted through sampling and analysis of the wastes from sampled households from each of the three categories. Palapye village does not have an engineered solid waste management system in place; hence the study can be used as a starting point. The v...

Spatial distribution of Diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), at the field and the regional level in Ethiopia

Abstract: Pheromone trap catches were used to study the spatial distribution of Diamondback moth (DBM), Plutella xylostella L., at both single field and regional levels. At the field level, the DBM population tended to remain within the cabbage field. At the regional level, DBM captures were highly influenced by geographic location and cropping systems. In highland areas, daily maximum temperatures positively influenced the aggregation index, whereas in the lowland areas, rainfall had a nega...

Cross Mating Studies among Five Fruit Fly Parasitoid Populations: Potential Biological Control Implications for Tephritid Pests

Abstract: The reproductive compatibility between four different species/populations of the tephritid parasitoid Psyttalia (Walker) species from Kenya and individuals of the morphologically identical Psyttalia concolor (Sze´pligeti) (Hymenoptera: Braconidae) from a laboratory culture in Italy used in augmentative biological control of olive fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae) was assessed through cross mating tests using single-pair and group mating methods. Reciprocal cros...

Importance of Plant Physical Cues in Host Acceptance for Oviposition by Busseola Fusca

Abstract: Plant and surrogate stems exhibiting specific combinations of physical cues were used to determine which plant-related stimuli influence the oviposition of Busseola fusca (Fuller) (Lepidoptera: Noctuidae). The number of eggs and egg batches laid per female increased with an increase in diameter of both natural and artificial stems. Direct observations of the oviposition behaviour (walking, antennating, and sweeping with the ovipositor) indicated that the female moths preferred ovip...

Comparison of five Allopatric Fruit Fly Parasitoid Populations (Psyttalia species) (Hymenoptera: Braconidae) from Coffee Fields using Morphometric and Molecular Methods

Abstract: Morphometric studies of five allopatric parasitoid populations (genus Psyttalia Walker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka, Kenya) were compared with individuals of Psyttalia concolor (Sze´pligeti), a species released in several biological control programmes in the Mediterranean Region since the 20th Century. Analyses of wing vein measurements showed the second submarg...

Is quality more important than quantity? Insect behavioural responses to changes in a volatile blend after Stemborer Oviposition on an African grass

Abstract: Plants subjected to insect attack usually increase volatile emission which attracts natural enemies and repels further herbivore colonization. Less is known about the capacity of herbivores to suppress volatiles and the multitrophic consequences thereof. In our study, the African forage grass, Brachiaria brizantha, was exposed to ovipositing spotted stemborer, Chilo partellus, moths. A marked reduction in emission of the main volatile, (Z)-3-hexenyl acetate (Z3HA),occurred followin...

Flight and Oviposition Behaviour of the African Stem borer, Busseola Fusca , on Various Host Plant Species

Abstract: The African stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae), is an important pest of maize and sorghum in sub-Saharan Africa. As in many other lepidopteran insects, the ability of B. fusca to recognize and colonize a variety of plants is based on the interaction between its sensory systems and the physical and chemical characteristics of its immediate environment. In this study, we tried to identify the behavioural steps of B. fusca leading to host selection and ovipos...

Effects of Nitrogen and Potassium Combinations on Yields and Infestations of Maize by Busseola fusca (Lepidoptera: Noctuidae) in the Humid Forest of Cameroon

Abstract: Field trials were set up in the humid forest zone of Cameroon to investigate the effects of combinations of different rates of nitrogen (N) (0, 60, and 120 kg N ha 1) and potassium (K) (0, 80, and 160 kg K ha 1) applied to the soil on the incidence and damage of the noctuid stemborer Busseola fusca (Fuller), and on maize, Zea mays L., yield. Each N/K combination had an insecticide control to assess yield losses due to borers. In contrast to N, K had no effect on plant growth and bo...

Desmodium Species and Associated Biochemical Traits for Controlling Striga species: Present and Future Prospects

Abstract: We discovered serendipitously a new and highly effective intervention against Striga spp., including Striga hermonthica (African witchweed), in cereals, which involves intercropping with cattle fodder legumes, Desmodium spp., including D. uncinatum. Although soil shading and additional nitrogen made some contribution to the reduction of S. hermonthica infestation, an allelopathic mechanism associated with the intercrop was a major factor. Root exudates of D. uncinatum contain novel...

Resource allocation and bionomics of indigenous and exotic Cotesia (Hymenoptera: Braconidae) species reared on Sesamia calamistis

Abstract: The braconid larval parasitoids Cotesia chilonis (Matsumura), C. flavipes Cameron and a strain of Cotesia sesamiae (Cameron) from coastal Kenya, reared at the International Centre of Insect Ecology and Physiology, were introduced at the International Institute of Tropical Agriculture in the Republic of Benin for suitability testing on West African stemborers prior to release. C. chilonis was originally collected in Japan while C. flavipes was imported into Kenya from Pakistan. The ...


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