Economic thresholds of Wheat streak mosaic, feedlot cost of gain prediction, and joint adoption of cow-calf production practices

Wheat streak mosaic (WSM), caused by Wheat streak mosaic virus, which is transmitted by the wheat curl mite (Aceria tosichella Keifer), is the most widespread and economically important virus disease affecting winter wheat in the Great Plains of the United States. Because there is no curative treatment, the disease can lead to significant yield loss, rendering continuation of mid-season input application uneconomical. This dissertation determines three economic thresholds for WSM beyond which further input applications become uneconomical. Results show varying thresholds depending on the date of disease severity assessments. Results indicate potential to save resources by discontinuing mid-season input applications and introducing cattle for grazing, in about 14% of the sampled plots.Feedlots use cost of gain (COG) to evaluate the tradeoff between purchasing heavier feeders or lighter feeders. Typically, ex-post COG for the feeding period just finished is used as a naïve projection for future closeout. However, such a naïve estimate may mask the effect of varying corn price and seasonality of cattle feeding efficiency on COG. This dissertation constructs an ex-ante COG prediction model to help facilitate more accurate estimation of expected COG, and thus corresponding feedlot purchase breakeven price, for lighter animals relative to heavier animals (800-850 pounds). Results show that the constructed model predicts COG more accurately than the naïve model. Results also show small reduction in price spreads between feeder market price and breakeven price for lighter weights when the predicted COG is used in calculating the breakeven price.Existing studies on adoption of cow-calf management practices tend to treat practices individually and by implication ignore the possibility that some practices are more likely to be jointly adopted. This dissertation uses market basket analysis to bundle practices based on the likelihood of joint adoption. Results show that dehorning plus polled genetics (horn management), deworming, and castration are the top three most widely adopted practices and are more likely to be jointly adopted in varying combinations with other practices. Results indicate higher conditional likelihood of vaccination if both feed bunks and 45-day weaning are adopted in addition to the top three practices

Contribution of Non-Timber Forest Products to Rural Household Income in Zambia

Non-timber forest products (NTFPs) play an important role in supporting rural livelihoods and food security in Zambia. NTFP-dependent households are poorer, have younger household heads with lower levels of education, and are located closer to district towns than other rural households are. NTFPs are a particularly important source of income in Luapula, Northwestern and Western provinces. • Income from woodfuel represented the greatest share of income for households that participated in NTFPs, and it was the most commonly reported business activity, with 68% of NTFP households reporting income from charcoal and firewood. NTFPs contribute an average of 32% to total household income among participants, with the poorest being more dependent on these sources. • Given the widespread demand for woodfuel and other forest products, it is likely that rural households will continue to engage in the extraction and trade of NTFPs as a business activity. However, charcoal production, if left unchecked, could compromise the integrity of forests and adversely affect the availability of other NTFPs. In order to reduce households’ reliance on charcoal/firewood as an income source, outreach efforts could promote other NTFPs such as wild honey, ants, and mushrooms as business activities. Mushrooms, ants, and caterpillars may particularly be important activities for female-headed households, as more female-headed households derived income from these sources.NON-TIMBER FOREST, ZAMBIA, Agricultural and Food Policy, Consumer/Household Economics,

Conceptualising farming systems for agricultural development research: cases from Eastern and Southern Africa

In the context of broad scale system changes (e.g. climate change) and the prioritisation of impact-at-scale development, there is a particular need for farming systems research (FSR) to improve our understanding of the links between systems at multiple scales. Drawing on three empirical case studies of large-scale agricultural interventions in eastern and southern Africa, we highlight problems that arise from conceiving and justifying interventions on the basis of the simple aggregation of farms into large collective systems. We review changes in the approach and concepts of FSR and point to the value of farming systems concepts that go beyond these aggregations, and find ways to capture the multi-level system dynamics that link on-farm decision making to broader political, social, and environmental changes. Recent attempts at more accurately conceptualising the domain of FSR, and drawing distinctions between ‘farms’, ‘systems’, and ‘systems of farming’, represent a useful contribution to such work

Underpinning Sustainable Vector Control through Informed Insecticide Resistance Management

Background: There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia’s programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions. Methodology/Principal Findings: A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids,DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s. Conclusions/Significance: Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management pla

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Climate Trends and Farmers’ Perceptions of Climate Change in Zambia

In Zambia like in many other developing countries, the agricultural sector is highly dependent on rain-fed production and therefore vulnerable to weather shocks. Maize is the primary staple crop in Zambia, and is widely grown by smallholder farmers throughout the country, with a dual cassava-maize regime found only in the northern region. Among the smallholder farmers almost all production is rain-fed with very few farmers using mechanized irrigation. Climate change therefore has the potential to significantly reduce agricultural production and exacerbate poverty and food insecurity

Climate Trends and Farmers’ Perceptions of Climate Change in Zambia

Despite some overlap between farmers’ observations and climate patterns found in the meteorological records, the meteorological data do not support the perception that is an increase in intra-season variability in rainfall. Therefore, a complete picture of climate change requires contributions from multiple knowledge systems

What Explains Minimal Usage of Minimum Tillage Practices in Zambia? Evidence from District-Representative Data.

Conservation farming (CF) practices are widely considered to be important components of sustainable agricultural development in Sub-Saharan Africa because of their potential to raise farm productivity and incomes while maintaining or improving soil quality and reducing vulnerability to variable climatic conditions. CF in Zambia can be traced to the 1980s when government, private sector, and donor communities started promoting CF as an alternative set of agronomic practices for Zambian smallholders (Haggblade and Tembo 2003)

What Explains Minimal Usage of Minimum Tillage Practices in Zambia? Evidence from District-representative Data.

Conservation farming (CF) practices are widely considered to be important components of sustainable agricultural development in Sub-Saharan Africa because of their potential to raise farm productivity and incomes while maintaining or improving soil quality and reducing vulnerability to variable climatic conditions. CF in Zambia can be traced to the 1980s when government, private sector, and donor communities started promoting CF as an alternative set of agronomic practices for Zambian smallholders (Haggblade and Tembo 2003)