Correction: Synergies of integrated pest and pollinator management in avocado farming in East Africa: An ex-ante economic analysis.

[This corrects the article DOI: 10.1371/journal.pone.0271241.].

Pollinator-dependent crops significantly contribute to diets and reduce household nutrient deficiencies in sub-Saharan Africa.

Recent literature highlights the potential of animal pollinator-dependent (PD) crops in enhancing food and nutrition security, although there is a lack of detailed household-level estimates. In this study, we investigate the nutrient composition, productivity, and contribution of PD and pollinator-independent (PI) crops to household nutrition in four sub-Saharan African (SSA) countries. We also evaluate the impact of reallocating resources from PI crops to PD crops on nutrient deficiencies, utilizing nationally representative panel data from three waves and over 30,000 household-year observations. Our findings reveal that PD crops exhibit higher micronutrient content per unit, albeit with lower macronutrient content compared to PI crops. PI crops have higher yield of calories per hectare while PD crops have higher vitamin A yield per hectare. However, protein and iron yield for PD and PI crops varies across countries. PI crops predominantly contribute to macronutrients and iron, while PD crops significantly contribute to vitamin A production. Our econometric results demonstrate that increasing the cultivation of PD crops relative to PI crops reduces the prevalence of nutrient deficiencies and increases crop income without compromising macronutrients production. This suggests that greater investment in PD crop production can be an integral approach to achieving nutrition security in SSA.

Economic, health, and environmental burden of Tuta absoluta (Lepidoptera: Gelechiidae), in tomato production in Kenya and Uganda.

The negative effects of pest infestation on agricultural production cannot be underestimated. There have been several efforts to control these pests, chiefly through the use of synthetic pesticides. However, the continuous use of the chemicals causes pest resistance and resurgence and presents high human and environmental risks. This study examines the economic, health, and environmental impacts of Tuta absoluta (Meyrick 1917), an economically important pest in tomato production, among smallholder farmers in selected counties in Kenya and Uganda. Economic Impact Quotient and gross margin analysis were used on data obtained from a random sample of 316 and 345 tomato growers in Kenya and Uganda, respectively. The results show a significant impact of T. absoluta on tomato production in both countries. On average, the tomato growers earned a gross income of $38,123 and $11,627 in Kenya and Uganda, respectively, with synthetic chemicals for the management of T. absoluta contributing 66-78% of the cost of production. The opportunity cost lost due to forgoing pesticide for management of the pest, and instead replacing it with an integrated pest management package was valued between $8 and $646 in Kenya and $895 in Uganda, respectively, using net present value through the most pessimistic scenario, while benefit-cost ratio was $1 and $5 in Kenya and Uganda, respectively.

Production, consumption, and market supply of edible crickets: insights from East Africa.

Globally, crickets are gaining recognition as a valuable alternative protein source for human consumption due to their lower resource requirement and ecological footprint compared to traditional livestock. In this paper, we examine strategies that may expedite the sustainable domestication of crickets as a food source. Using survey data from 306 households in western Kenya, we find that supplying cricket production starter kits, granting access to credit facilities, encouraging participation in farmer groups, and fostering partnerships can enhance the adoption of cricket farming. Moreover, we provide new evidence that institutional training significantly increases cricket yields while embracing cricket consumption (i.e. entomophagy) increases market supply. These findings underscore the importance of technical training, provision of production starter kits, and raising awareness about entomophagy to achieve sustainable mass production and adoption of cricket farming.

The economic performance of mango integrated pest management practices at different scales of production.

Integrated pest management (IPM) strategies are being promoted to suppress tephritid fruit fly infestation and reduce economic damage in mango production. However, research on their economic performance across different mango production scales (measured by the number of mango trees) is limited. This study estimated the economic benefits of IPM practices (parasitoids, orchard sanitation, food bait, biopesticides, male annihilation technique, and their combinations) in Kenya's small-, medium-, and large-scale mango production systems. We used the value-cost ratio (VCR) and net present value methods to estimate the heterogeneous economic performance of IPM practices using data from two unique farm surveys. On average, all IPM practices were profitable across various production scales. However, we found that these practices were more profitable for medium-scale farmers than for small- and large-scale farmers. The results show that farmers need a minimum of 9-17 trees, depending on the practice used, to break even and that there are little to no economic benefits to using IPM practices for farmers with more than 320 mango trees. The male annihilation technique was the most profitable practice, with a VCR of 36, and consequentially, the most adopted practice across all scales of production. Overall, we found significant heterogeneity in the profitability of IPM practices across different scales of production. The reason for the lack of profitability of IPM on large-scale farms remains unclear and warrants further investigation.

Synergies of integrated pest and pollinator management in avocado farming in East Africa: An ex-ante economic analysis.

Using synthetic pesticides to manage pests can threaten pollination services, affecting the productivity of pollination-dependent crops such as avocado. The need to mitigate this negative externality has led to the emergence of the concept of integrated pest and pollinator management (IPPM) to achieve both pest and pollinator management, leading to complementary or synergistic benefits for yield and quality of the harvest. This paper aims to evaluate the potential economic and welfare impact of IPPM in avocado production systems in Kenya and Tanzania. We utilize both primary and secondary data and employed the economic surplus model. On average the potential economic gain from the adoption of IPPM is US$ 66 million annually in Kenya, with a benefit-cost ratio (BCR) of 13:1, while in Tanzania US$ 1.4 million per year, with a BCR of 34:1. The potential benefits from IPPM intervention gains are expected to reduce the number of poor people in Kenya and Tanzania by 10,464 and 1,255 people per year respectively. The findings conclude that policies that enhance the adoption of IPPM can fast-track economic development and therefore improve the livelihoods of various actors across the avocado value chain.

Evaluating the growth and cost-benefit analysis of feeding improved indigenous chicken with diets containing black soldier fly larva meal.

The high cost of feed has been the major hindrance to a hindrance to the growth, sustainability, profitability, and expansion of poultry production. Black soldier fly larva (BSFL) meal is one of the most promising alternative protein sources widely accepted globally. This study evaluated the growth performance of improved indigenous chicken (IIC)-fed diets containing different inclusion levels of BSFL meals. The BSFL meal inclusion rates included 0% (Diet0), 5% (Diet1), 10% (Diet2), 15% (Diet3), and 20% (Diet4) as replacement to the expensive fish meal in chick and grower diets. Our results showed that diet significantly affected the average daily feed intake, feed conversion ratio, and average daily weight gain of the chicks. The average daily weight gain and feed conversion ratio, except average daily feed intake of the growers, was not significantly affected by diets. The gross profit margin, cost-benefit ratio, and return on investment of feeding birds with BSFL meal varied significantly. The highest cost-benefit ratio of 2.12 was recorded for birds fed on Diet4. Our findings demonstrate that insect-based feeds can successfully and cost-effectively replace fish meal up to 20% without compromising the growth performance of the birds. Therefore, BSFL meal could be incorporated as an essential part of poultry feed production for IIC, potentially reducing the total feed cost while maintaining optimal production and reducing the cost of meat and egg products.

Farmer perceptions and willingness to pay for novel livestock pest control technologies: A case of tsetse repellent collar in Kwale County in Kenya.

Tsetse-transmitted Animal African Trypanosomosis (AAT) is one of the most important constraints to livestock development in Africa. Use of trypanocides has been the most widespread approach for the management of AAT, despite the associated drug resistance and health concerns associated with drug metabolites in animal products. Alternative control measures that target tsetse fly vectors of AAT, though effective, have been hard to sustain in part because these are public goods applied area-wide. The International Centre of Insect Physiology and Ecology (icipe) and partners have developed and implemented a novel tsetse repellent collar (TRC) applied on animals to limit contact of tsetse flies and livestock, thereby reducing AAT transmission. The TRC has now advanced to commercialization. A household-level survey involving 632 cattle keeping households, was conducted in Shimba Hills region of Kwale County, where field trials of the TRC have been previously conducted to assess farmers' knowledge, perception, and practices towards the management of tsetse flies, their willingness to pay (WTP) for the TRC, and factors affecting the WTP. Almost all the respondents (90%) reported that tsetse flies were the leading cattle infesting pests in the area. About 22% of these correctly identified at least four AAT clinical signs, and even though many (68%) used trypanocidal drugs to manage the disease, 50% did not perceive the drug as being effective in AAT management (50%). Few respondents (8%) were aware of the harmful effects of trypanocidal drugs. About 89% of the respondents were aware of icipe TRC, and 30% of them were using the field trial collars during the survey. Sixty-three (63%) of them were willing to pay for the TRC at the same cost they spend treating an animal for AAT. On average farmers were willing to pay KES 3,352 per animal per year. Male educated household heads are likely to pay more for the TRC. Moreover, perceived high AAT prevalence and severity further increases the WTP. Wider dissemination and commercialization of the herd-level tsetse control approach (TRC) should be encouraged to impede AAT transmission and thus enhance food security and farm incomes among the affected rural communities. Besides the uptake of TRC can be enhanced through training, especially among women farmers.

The potential economic benefits of controlling trypanosomiasis using waterbuck repellent blend in sub-Saharan Africa.

Trypanosomiasis is a significant productivity-limiting livestock disease in sub-Saharan Africa, contributing to poverty and food insecurity. In this paper, we estimate the potential economic gains from adopting Waterbuck Repellent Blend (WRB). The WRB is a new technology that pushes trypanosomiasis-transmitting tsetse fly away from animals, improving animals' health and increasing meat and milk productivity. We estimate the benefits of WRB on the production of meat and milk using the economic surplus approach. We obtained data from an expert elicitation survey, secondary and experimental sources. Our findings show that the adoption of WRB in 5 to 50% of the animal population would generate an economic surplus of US$ 78-869 million per annum for African 18 countries. The estimated benefit-cost ratio (9:1) further justifies an investment in WRB. The technology's potential benefits are likely to be underestimated since our estimates did not include the indirect benefits of the technology adoption, such as the increase in the quantity and quality of animals' draught power services and human and environmental health effects. These benefits suggest that investing in WRB can contribute to nutrition security and sustainable development goals.

Women's empowerment in agriculture and agricultural productivity: Evidence from rural maize farmer households in western Kenya.

This paper documents a positive relationship between maize productivity in western Kenya and women's empowerment in agriculture, measured using indicators derived from the abbreviated version of the Women's Empowerment in Agriculture Index. Applying a cross-sectional instrumental-variable regression method to a data set of 707 maize farm households from western Kenya, we find that women's empowerment in agriculture significantly increases maize productivity. Although all indicators of women's empowerment significantly increase productivity, there is no significant association between the women's workload (amount of time spent working) and maize productivity. Furthermore, the results show heterogenous effects with respect to women's empowerment on maize productivity for farm plots managed jointly by a male and female and plots managed individually by only a male or female. More specifically, the results suggest that female- and male-managed plots experience significant improvements in productivity when the women who tend them are empowered. These findings provide evidence that women's empowerment contributes not only to reducing the gender gap in agricultural productivity, but also to improving, specifically, productivity from farms managed by women. Thus, rural development interventions in Kenya that aim to increase agricultural productivity-and, by extension, improve food security and reduce poverty-could achieve greater impact by integrating women's empowerment into existing and future projects.

Proton Conductivity of Nafion/Ex-Situ Sulfonic Acid-Modified Stöber Silica Nanocomposite Membranes As a Function of Temperature, Silica Particles Size and Surface Modification.

The introduction of sulfonic acid modified silica in Nafion nanocomposite membranes is a good method of improving the Nafion performance at high temperature and low relative humidity. Sulfonic acid-modified silica is bifunctional, with silica phase expected to offer an improvement in membranes hydration while sulfonic groups enhance proton conductivity. However, as discussed in this paper, this may not always be the case. Proton conductivity enhancement of Nafion nanocomposite membranes is very dependent on silica particle size, sometimes depending on experimental conditions, and by surface modification. In this study, Sulfonated Preconcentrated Nafion Stober Silica composites (SPNSS) were prepared by modification of Stober silica particles with mercaptopropyltriethoxysilane, dispersing the particles into a preconcentrated solution of Nafion, then casting the membranes. The mercapto groups were oxidized to sulfonic acids by heating the membranes in 10 wt % hydrogen peroxide for 1 h. At 80 °C and 100% relative humidity, a 20%-30% enhancement of proton conductivity was only observed when sulfonic acid modified particle less than 50 nm in diameter were used. At 120 °C, and 100% humidity, proton conductivity increased by 22%-42% with sulfonated particles with small particles showing the greatest enhancement. At 120 °C and 50% humidity, the sulfonated particles are less efficient at keeping the membranes hydrated, and the composites underperform Nafion and silica-Nafion nanocomposite membranes.

The role of gender on malaria preventive behaviour among rural households in Kenya.

BACKGROUND: Malaria remains a major health and development challenge in the sub-Saharan African economies including Kenya, yet it can be prevented. Technologies to prevent malaria are available but are not universally adopted by male- and female-headed households. The study thus, examined the role of gender in malaria prevention, examining adoption behaviour between male- and female-headed households in Kenya. METHODS: The study uses a recent baseline cross-section survey data collected from 2718 households in parts of western and eastern Kenya. Two separate models were estimated for male- and female-headed households to determine if the drivers of adoption differ between the two categories of households. RESULTS: The findings from the study show that: access to public health information, residing in villages with higher experience in malaria prevention, knowledge on the cause and transmission of malaria significantly increase the number of practices adopted in both male- and female-headed households. On the other hand, formal education of the household head and livestock units owned exhibited a positive and significant effect on adoption among male-headed households, but no effect among female-headed households. CONCLUSIONS: The findings from thus study suggest that universal policy tools can be used to promote uptake of integrated malaria prevention practices, for female- and male-headed households.

Processing, morphology, and water uptake of Nafion/ex situ Stöber silica nanocomposite membranes as a function of particle size.

Because of the bicontinuous phase structure of Nafion with small hydrophilic channels, formation of composites with silica colloids to improve thermal stability, hydration, and proton conductivity should be influenced by size and surface functionality of the colloids. To test this hypothesis, we prepared batches of silica particles between 20 and 400 nm in diameter with narrow polydispersities using a modified Stöber procedure. Some particles were subsequently surface-modified using mercaptopropyltriethoxysilane. Enough particles were mixed with Nafion in alcohols to achieve 5 wt % silica in the final membranes, which were made by casting and drying. Membrane top and bottom surface and cross-section morphologies were examined with AFM and SEM to determine how the particles were dispersed. We discovered that casting the membranes from dispersions with viscosities less than 65 cPs led to larger particles floating to the top surface of the membrane where they were easily dislodged from the dry membrane. Membranes cast from more viscous solutions exhibited homogeneous distributions of particles. Water uptake was over 60% higher in nanocomposites with unmodified silica particles than for Nafion and about 15% higher than for Nafion with in situ generated silica particles, but showed no trend in water uptake correlating with particle size. Surface silated particles of all sizes appeared to have reduced water uptake relative to Nafion alone.

Strong, low-density nanocomposites by chemical vapor deposition and polymerization of cyanoacrylates on aminated silica aerogels.

Strong polymer-silica aerogel composites were prepared by chemical vapor deposition of cyanoacrylate monomers onto amine-modified aerogels. Amine-modified silica aerogels were prepared by copolymerizing small amounts of (aminopropyl)triethoxysilane with tetraethoxysilane. After silation of the aminated gels with hexamethyldisilazane, they were dried as aerogels using supercritical carbon dioxide processing. The resulting aerogels had only the amine groups as initiators for the cyanoacrylate polymerizations, resulting in cyanoacrylate macromolecules that were higher in molecular weight than those observed with unmodified silica and that were covalently attached to the silica surface. Starting with aminated silica aerogels that were 0.075 g/cm(3) density, composite aerogels were made with densities up to 0.220 g/cm(3) and up to 31 times stronger (flexural strength) than the precursor aerogel and about 2.3 times stronger than an unmodified silica aerogel of the same density.