Characterization of phenotypic traits associated with anthracnose resistance in selected common bean (Phaseolus vulgaris L.) breeding material.

Anthracnose caused by Colletotrichum lindemuthianum is the major common bean disease worldwide causing complete yield loss under favourable disease conditions. This study aimed to determine phenotypic traits associated with anthracnose resistance for future use in breeding programmes. Twenty-two common bean varieties (CBVs) were selected basing on susceptibility to anthracnose, advanced breeding lines, improved variety resembling advanced breeding lines and the farmer variety widely grown in Tanzania. Selected varieties were planted in anthracnose hotspot fields and the same CBVs were planted in a screen house to validate resistance to anthracnose. Anthracnose infection score, leaf length, leaf width, length of fifth internode, length of petiole, plant vigour, canopy height and canopy width were recorded. Data on number of plants emerging; days to flowering; days to maturity; plant stands at harvest; and grain yield were also collected and analysed using R software. Phenotypic traits evaluated differed significantly among genotypes, environment and genotype by environment interaction. Seventy-five percent of phenotypic traits evaluated were positively correlated to anthracnose resistance. Highly-strong correlations to anthracnose were observed on number of days to maturity, plant stands at harvest, plant vigour and grain yield. Leaf length, leaf width, length of fifth internode, length of petiole and number of stands emerging were strongly correlated to anthracnose resistance. Additive main effects and multiplicative interaction analysis (AMMI) revealed highest contribution of environment on anthracnose infection-58.9% and grain yield -84.9% compared to genotype effects on anthracnose infection -32.7% and grain yield-15.7%. Based on these results, four traits - plant vigour, number of days to maturity, number of plant stands at harvest and grain yield - are recommended for selecting anthracnose-resistant varieties. NUA 48, NUA 64 and RWR 2154 were superior varieties, resistant to anthracnose and high yielding, while Sweet Violet and VTT 923-23-10 were most stable varieties across environments. Further on-farm research is suggested to assess their performance and identify traits preferred by farmers.

A simplified non-greenhouse hydroponic system for small-scale soilless urban vegetable farming.

Majority of under-developed countries continue to face a challenge of food insecurity around urban areas resulting from factors such as; limited access to arable land. This study aimed at developing a simplified low-tech hydroponic system for growing leafy vegetables alongside testing its economic viability. This was intended to support urban vegetable production and henceforth contributing to food security more so in under-developed states dealing with the challenge of increasing urban population vs. reducing arable land around urban/ peri-urban areas. A hydroponic unit for growing 60 leafy vegetables (using lettuce as a study crop) under non-controlled environmental conditions was designed and developed using low-cost and low-tech materials. Kratky hydroponic method which involves growing crops using water as a media without the need for water pumps and electricity was used. A study was also carried out to assess the profitability of the system. The results indicated a: net present values of 16.37$, internal rate of return of 12.57%, profitability index of 1.1 and non-discounted payback period of approximately 8 months (4 cropping seasons). These findings showed that the system has the potential to improve urban food production and availability in especially in developing countries in a profitable manner. Vegetable production using the hydroponic system can also contribute to:•tachievement of sustainable development goals, 2 (zero hunger) and 3 (good health and wellbeing);•improvement in urban agriculture production and income generation among urban farmers;•enhanced adoption of low-cost, low-tech, environmental-friendly and sustainable farming systems.

Plant growth-promoting rhizobacterial biofertilizers for crop production: The past, present, and future.

Recent decades have witnessed increased agricultural production to match the global demand for food fueled by population increase. Conventional agricultural practices are heavily reliant on artificial fertilizers that have numerous human and environmental health effects. Cognizant of this, sustainability researchers and environmentalists have increased their focus on other crop fertilization mechanisms. Biofertilizers are microbial formulations constituted of indigenous plant growth-promoting rhizobacteria (PGPR) that directly or indirectly promote plant growth through the solubilization of soil nutrients, and the production of plant growth-stimulating hormones and iron-sequestering metabolites called siderophores. Biofertilizers have continually been studied, recommended, and even successfully adopted for the production of many crops in the world. These microbial products hold massive potential as sustainable crop production tools, especially in the wake of climate change that is partly fueled by artificial fertilizers. Despite the growing interest in the technology, its full potential has not yet been achieved and utilization still seems to be in infancy. There is a need to shed light on the past, current, and future prospects of biofertilizers to increase their understanding and utility. This review evaluates the history of PGPR biofertilizers, assesses their present utilization, and critically advocates their future in sustainable crop production. It, therefore, updates our understanding of the evolution of PGPR biofertilizers in crop production. Such information can facilitate the evaluation of their potential and ultimately pave the way for increased exploitation.

Plant-Rich Field Margins Influence Natural Predators of Aphids More Than Intercropping in Common Bean.

Field margins support important ecosystem services including natural pest regulation. We investigated the influence of field margins on the spatial and temporal distribution of natural enemies (NEs) of bean pests in smallholder farming systems. We sampled NEs from high and low plant diversity bean fields using sweep netting and coloured sticky traps, comparing monocropped and intercropped farms. NEs collected from within crops included predatory bugs, lacewings, predatory flies, parasitic flies, parasitic wasps, lady beetles, and a range of other predatory beetles; with the most dominant group being parasitic wasps. Overall, high plant diversity fields had a higher number of NEs than low-diversity fields, regardless of sampling methods. The field margin had a significantly higher number of lacewings, parasitic wasps, predatory bugs, syrphid flies, and other predatory beetles relative to the crop, but beneficial insects were collected throughout the fields. However, we observed marginally higher populations of NEs in intercropping than in monocropping although the effect was not significant in both low and high plant diversity fields. We recommend smallholder farmers protect the field margins for the added benefit of natural pest regulation in their fields.

Status of carotenoids in elite and landrace maize genotypes: Implications for provitamin A biofortification in Tanzania.

Maize is among the crops containing carotenoids that are easily converted to vitamin A and have an enormous influence on consumers' health. Principally maize has high calories and proteins but has less number of other micronutrients such as vitamin A. Societies that use maize as their main and sole staple food are likely to be affected by vitamin A deficiency. Thus, development and production of maize varieties rich in micronutrients and vitamin A are important for improved health. This study characterized 5 carotenoid components in maize genotypes grown in Tanzania as a strategy for improving vitamin A content in maize. The study involved maize landraces, commercial or elite varieties, and inbred lines in determining their potential for provitamin A breeding programs for nutrition improvement. The study found that mean concentration of important carotenoid components, i.e., alpha carotene (AC), beta-carotene (BC), beta-cryptoxanthin (BCX), lutein (LU), zeaxanthin (ZX), provitamin A (ProVA), non-provitamin A (Non-ProVA), and total carotenoids (TC) varied significantly (P < 0.001) among maize genotypes. The 3 maize groups studied (landraces, commercial varieties, and breeding materials (BMs) varied significantly. For maize landraces, the concentration (µg/g) of studied carotenoids were AC (0.13-2.67), BC (0.60-3.72), BCX (0.36-1.01), ProVA (0.89-5.29), Retinol (0.25-0.87), LU (2.37-16.97). ZX (0.16-4.41), Non-ProVA (2.4-19.01), and TC (3.68-25.27); in commercial or elite maize varieties were (in µg/g): AC (0.31-3.84), BC (0.56-6.5), BCX (0.46-2.58), ProVA (0.92-11.80), Retinol (0.15-1.82), LU (3.28-22.39). ZX (0.05-11.31), Non-ProVA (2.56-28.81), and TC (4.23-37.84); and for maize BMs AC (0.53-6.64), BC (1.92-13.87), BCX (0.65-6.51), ProVA (2.69-18.62), Retinol (0.5-3.1), LU (4.86-34.99), ZX (0.06-18.58), Non-ProVA (4.8-53.57), and TC (9.86-76.94). Furthermore, the study found that the concentration of studied carotenoids was higher in pigmented (yellow or red) maize genotypes than in white maize genotypes. The current study found an appreciable amount of ProVA in studied materials, including maize landraces, commercial yellow varieties, and CIMMYT lines. The concentration of ProVA and retinol determined in studied maize genotypes were below 15 µg/g a daily vitamin A requirement, thus based on the current ProVA and retinol status it is difficult to meet Vitamin A requirement. Therefore, these maize genotypes with promising levels of carotenoid components are potential breeding materials that can be used in maize provitamin A biofortification program for improved food nutrition and livelihoods in Tanzania.

Field Margin Plants Support Natural Enemies in Sub-Saharan Africa Smallholder Common Bean Farming Systems.

Flower-rich field margins provide habitats and food resources for natural enemies of pests (NEs), but their potential, particularly in the tropics and on smallholder farms, is poorly understood. We surveyed field margins for plant-NE interactions in bean fields. NEs most often interacted with Bidens pilosa (15.4% of all interactions) and Euphorbia heterophylla (11.3% of all interactions). In cage trials with an aphid-infested bean plant and a single flowering margin plant, the survival of Aphidius colemani, the most abundant parasitoid NE in bean fields, was greater in the presence of Euphorbia heterophylla than Bidens pilosa, Tagetes minuta, and Hyptis suaveolens. UV-fluorescent dye was applied to flowers of specific field margin plant species and NE sampled from within the bean crop and field margins using sweep-netting and pan-traps respectively. Captured insects were examined for the presence of the dye, indicative of a prior visit to the margin. Lady beetles and assassin bugs were most abundant in plots with B. pilosa margins; hoverflies with T. minuta and Parthenium hysterophorus margins; and lacewings with T. minuta and B. pilosa margins. Overall, NE benefitted from field margin plants, and those possessing extra floral nectaries had an added advantage. Field margin plants need careful selection to ensure benefits to different NE groups.

Effects of agrochemicals on the beneficial plant rhizobacteria in agricultural systems.

Conventional agriculture relies heavily on chemical pesticides and fertilizers to control plant pests and diseases and improve production. Nevertheless, the intensive and prolonged use of agrochemicals may have undesirable consequences on the structure, diversity, and activities of soil microbiomes, including the beneficial plant rhizobacteria in agricultural systems. Although literature continues to mount regarding the effects of these chemicals on the beneficial plant rhizobacteria in agricultural systems, our understanding of them is still limited, and a proper account is required. With the renewed efforts and focus on agricultural and environmental sustainability, understanding the effects of different agrochemicals on the beneficial plant rhizobacteria in agricultural systems is both urgent and important to deduce practical solutions towards agricultural sustainability. This review critically evaluates the effects of various agrochemicals on the structure, diversity, and functions of the beneficial plant rhizobacteria in agricultural systems and propounds on the prospects and general solutions that can be considered to realize sustainable agricultural systems. This can be useful in understanding the anthropogenic effects of common and constantly applied agrochemicals on symbiotic systems in agricultural soils and shed light on the need for more environmentally friendly and sustainable agricultural practices.

The Effects of Cultivating Tobacco and Supplying Nitrogenous Fertilizers on Micronutrients Extractability in Loamy Sand and Sandy Soils.

This research was conducted to evaluate the trends of the extractable micronutrients boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in soils differing in textures and collected before tobacco cultivation, and in after unfertilized and fertilized (N10P18K24 and CAN 27%) plots. The soils and tobacco leaves were assessed on the contents of the micronutrients after unfertilized and fertilized tobacco cultivation. In soils, tobacco cultivation with fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.10, 11.03, 8.86, and 0.08 mg kg-1, respectively, but decreased the extractable B by 0.04 mg kg-1. The effects of fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.14, 14.29, 9.83, and 0.24 mg kg-1, respectively, but decreased B by 0.08 mg kg-1. The combination effects of tobacco cultivation and fertilization increased the extractable Cu, Fe, Mn, and Zn by 0.24, 25.32, 18.69, and 0.32 mg kg-1, respectively, but decreased the extractable B by 0.12 mg kg-1. The results revealed that the solubility of the extractable Zn, Mn, Cu, and Fe in soils were increased by both tobacco and fertilization, but the extractable B was decreased. The fertilization of the studied soils with NPK + CAN fertilizers significantly increased the concentration of the extractable micronutrients in tobacco leaves. Based on the findings of this study, further research must be conducted to investigate the effects of tobacco cultivation on soil health and fertility beyond considering only soil pH, SOC, micronutrients, and macronutrients. These studies should include the relationship between soil fertility (pH, texture, CEC, base saturation, etc.), micronutrients, and agronomic practices on the effect of tobacco cultivation on the extractability of B, Cu, Fe, Mn, and Zn.

Natural Pest Regulation and Its Compatibility with Other Crop Protection Practices in Smallholder Bean Farming Systems.

Common bean (Phaseolus vulgaris) production and storage are limited by numerous constraints. Insect pests are often the most destructive. However, resource-constrained smallholders in sub-Saharan Africa (SSA) often do little to manage pests. Where farmers do use a control strategy, it typically relies on chemical pesticides, which have adverse effects on the wildlife, crop pollinators, natural enemies, mammals, and the development of resistance by pests. Nature-based solutions -in particular, using biological control agents with sustainable approaches that include biopesticides, resistant varieties, and cultural tools-are alternatives to chemical control. However, significant barriers to their adoption in SSA include a lack of field data and knowledge on the natural enemies of pests, safety, efficacy, the spectrum of activities, the availability and costs of biopesticides, the lack of sources of resistance for different cultivars, and spatial and temporal inconsistencies for cultural methods. Here, we critically review the control options for bean pests, particularly the black bean aphid (Aphis fabae) and pod borers (Maruca vitrata). We identified natural pest regulation as the option with the greatest potential for this farming system. We recommend that farmers adapt to using biological control due to its compatibility with other sustainable approaches, such as cultural tools, resistant varieties, and biopesticides for effective management, especially in SSA.

Environmentally stable common bean genotypes for production in different agro-ecological zones of Tanzania.

Genotype by environment interaction (GxE) complicates the process of selecting genotypes suitable for quantitative traits like seed yield in beans, hence slows down the development and release of varieties by breeding programs. GxE study on seed yield in beans enables identification of stable genotypes across sites and best site(s) for discriminating the tested genotypes in terms of seed yield. The purpose of this study was to evaluate the influence of the environment, genotype, and genotype by environment interaction on seed yield stability and adaptability of common bean landraces, lines, and improved varieties across three different agro-ecologies in Tanzania. The 99 common bean genotypes (Landraces, lines, and improved varieties) were planted following alpha lattice design in three replications each contained five blocks with 20 plots. Soil properties from the experimental sites, days to 75% flowering, Seed yield, 100 seed weight, number of seeds/pod, and number of pods/plant were recorded. Data on seed yield and its components were analyzed using Additive main effect and multiplicative interaction (AMMI), genotype main effects plus genotype × environment interaction (GGE), and yield stability index (YSI). The AMMI revealed very highly significant (P ≤ 0.001) effects of genotypes, environmental, and genotype × environment interaction on all the traits. AMMI analysis revealed that genotype main effects accounted for 39.3% of the total sum square of seed yield, whereas the environment and genotype × environmental interaction accounted for 31.4% and 26.8 % respectively. Genotype main effects largely influenced the variation in days to 75% flowering (55.5%), number of pods/plant (49.2%), number of seeds/pod (73.3%), and 100 seed weight (71.2%). Among soil properties recorded, available soil phosphorus, soil pH, soil exchangeable K, Ca, and Na had a strong positive association with common bean seed yield, while soil organic carbon and total nitrogen exhibited a strong negative association with seed yield. GGE revealed that E1 (TARI-Selian) was the most discriminative and representative site for common bean genotypes seed yield. Based on the yield stability index, the most stable and high seed yielding genotypes were ACC 714, Selian 14, Selian 9, Katuku, and Msolini. The identified high seed yielding and stable genotypes can be further tested in participatory variety selection involving farmers and later on released as varieties and can also be used for different breeding purposes in different agro-ecologies of Tanzania.

Linking rhizosphere bacterial diversity and soil fertility in tobacco plants under different soil types and cropping pattern in Tanzania: A pilot study.

Tobacco (Nicotiana tabacum L.), one of the major crop plants in Tanzania, cropping affects the level of soil fertility, but the reason has not been known. Plant rhizosphere plays an important role in affecting soil fertility through changing microbial composition. We planned a pilot study to understand the changes in microbial composition and soil nutrients in the rhizosphere soils of tobacco in three agro-ecological zone, namely Sikonge, Tabora and Urambo in Tanzania. This study assessed bacteriota composition using 16S rRNA sequencing and soil fertility in the rhizosphere of tobacco plants. The results showed that bacterial diversity in tobacco rhizosphere soils belonged to Proteobacteria phyla, associated significantly (p < 0.05) with solubilization of insoluble P, K and S. The solubilization of P, K and S in soils facilitates the availability of these nutrients to the tobacco plants (a heavy feeder crop) allows low levels of these nutrients in the soils for the subsequent crop. The Proteobacteria phyla also associated with an increase in soil N content through fixation. Therefore, bacteria diversity in tobacco rhizosphere influence solubilities of macronutrients (P, K, S) and quickly up taken by the tobacco plant and reduces their levels in soils, some bacteria involved in fixing N and increases total N in the soil.

Multilocation dataset on seed Fe and Zn contents of bean (Phaseolus vulgaris L.) genotypes grown in Tanzania.

There are over a hundred genotypes of Phaseolus vulgaris L. grown and consumed in Tanzania. Currently, identification of bean genotypes containing high seed iron and zinc contents has been the focus globally for common bean iron and zinc biofortification. Diversity in seed iron and zinc contents were investigated in 99 bean genotypes grown in Tanzania to identify high seed iron and zinc-containing genotypes for use in iron and zinc biofortification. Flour obtained by grinding seeds of each bean genotypes was used in the determination of iron and zinc concentrations. Data were subjected to analysis of variance (ANOVA) to determine significant differences among common bean genotypes in terms of seed iron and zinc contents. Additive main effects and multiplicative interaction (AMMI) and genotype plus genotype by environment interaction (GGE) were conducted to determine stability and adaptation across sites (TARI-Selian, SUA, and TARI-Uyole) of bean genotypes in terms of seed iron and zinc contents. Data in this data article show that some landraces had high seed iron and zinc contents compared to release varieties thus can be used for iron and zinc genetic biofortification in common beans breeding programs. For more explanation of the data presented in this data article, please follow the related research article "Environmental and genotypes influence on seed iron and zinc levels of landraces and improved varieties of common bean (Phaseolus vulgaris L.) in Tanzania" [1].

Prospects of Using Termite Mound Soil OrganicAmendment for Enhancing Soil Nutrition inSouthern Africa.

Termite mound soils are reportedly utilized as an alternative to NPK fertilizers by cashconstrained smallholder farmers in some parts of Southern Africa. However, there is limitedknowledge regarding their mineral nutritional value. The intention of this work was therefore toinvestigate the macro and micronutrient composition of different sections of the termite mounds;top, base and neighboring areas. The study approach involved physical and chemical analysis of 36sites across Pemba and Choma districts in Southern Zambia through collection of soil samples intriplicate at 0-20 cm depth, using a soil auger. Findings revealed that the soil pH had elevatedlevels in the base segments of the termite mounds compared with the top and the neighbouringsoils. However, elevated N, P and K levels were recorded in the top sections with significantdifferences (P < 0.05) in clay and silt composition observed. Additionally, metallic micronutrients,Cu and Zn were also found to be elevated in termite mounds in contrast to surrounding soils. Weconcluded that top termite mound soil should be considered as part of an integrated nutrientmanagement strategy by financially challenged smallholder farmers cultivating in light texturedsoils of southern Africa.

Whole-Genome Sequences of Three Plant Growth-Promoting Rhizobacteria Isolated from Solanum tuberosum L. Rhizosphere in Tanzania.

We present here the complete genome sequences of plant growth-promoting Klebsiella sp. strain MPUS7, Serratia sp. strain NGAS9, and Citrobacter sp. strain LUTT5, isolated from rhizosphere soils and tubers of potato (Solanum tuberosum L.) plants growing in the northern and southern highlands of Tanzania.

Extracts of Common Pesticidal Plants Increase Plant Growth and Yield in Common Bean Plants.

Common bean (Phaseolus vulgaris) is an important food and cash crop in many countries. Bean crop yields in sub-Saharan Africa are on average 50% lower than the global average, which is largely due to severe problems with pests and diseases as well as poor soil fertility exacerbated by low-input smallholder production systems. Recent on-farm research in eastern Africa has shown that commonly available plants with pesticidal properties can successfully manage arthropod pests. However, reducing common bean yield gaps still requires further sustainable solutions to other crop provisioning services such as soil fertility and plant nutrition. Smallholder farmers using pesticidal plants have claimed that the application of pesticidal plant extracts boosts plant growth, potentially through working as a foliar fertiliser. Thus, the aims of the research presented here were to determine whether plant growth and yield could be enhanced and which metabolic processes were induced through the application of plant extracts commonly used for pest control in eastern Africa. Extracts from Tephrosia vogelii and Tithonia diversifolia were prepared at a concentration of 10% w/v and applied to potted bean plants in a pest-free screen house as foliar sprays as well as directly to the soil around bean plants to evaluate their contribution to growth, yield and potential changes in primary or secondary metabolites. Outcomes of this study showed that the plant extracts significantly increased chlorophyll content, the number of pods per plant and overall seed yield. Other increases in metabolites were observed, including of rutin, phenylalanine and tryptophan. The plant extracts had a similar effect to a commercially available foliar fertiliser whilst the application as a foliar spray was better than applying the extract to the soil. These results suggest that pesticidal plant extracts can help overcome multiple limitations in crop provisioning services, enhancing plant nutrition in addition to their established uses for crop pest management.

The prebiotic potential of brewers' spent grain on livestock's health: a review.

The increasing interest from the feed as a source of energy towards specific nutrient-yielding compounds in feeds is amongst the latest developments from scientific and industrial communities. Apart from brewers' spent grain (BSG) being relatively inexpensive feed source, nutritious with high crude protein and minerals, recent studies have explored its potential as a source of prebiotics. Prebiotics are certain feeds that are comprised of non-digestive polysaccharides that can be fed to animals and modulate the balance and activities of microbial populations in the gut. The BSG contains arabinoxylans and ß-glucans whereby when consumed by animals, they promote the activity of beneficial bacteria particularly species from three genera of Bifidobacterium, Enterococcus, and Lactobacillus. The increased degradation of fibrous feed accelerates the production of short-chain fatty acids (SCFA) which serve as the primary energy sources for the anaerobic microbes. This elevated concentration of SCFA stimulates numerous physio-biological functions which include intestinal nutrients absorption, glucose balance, improvement of immunity, lipid metabolism, and suppression of pathogens such as Salmonella and Escherichia coli. To capitalize on the prebiotic potential of BSG, certain considerations need to be well taken care of and these include possible microbial dysfunctions such as rumen acidosis, different responses rates of animals due to variations in health status, age, and species as well as feed safety issues especially mycotoxin contamination which can jeopardize its inherited prebiotic benefits.

Effects of Nanoparticles of Metal Oxides on the Survival of the Entomopathogenic Nematode: Steinernema carpocapsae.

Nanoparticles (NPs) are technological engineered materials with unique physical and chemical properties, and dimension of less than 100 nm. Nanotechnology has developed at a rapid pace, resulting into tremendous wide application that has resulted into concerns and ecotoxicological consequences. The antimicrobial potentials of the nanoparticles have been extensively studied, however, little has been done on the allied health and environmental toxicity assessments. Thus, the current work evaluated the toxicity effects of the ZnO, TiO2 and Fe3O4 NPs on the survival of the entomopathogenic nematodes (Steinernema carpocapsae), as well as their growth inhibition effects on the nematode symbiotic bacteria (Xenorhabdus nematophila). The metal oxides NPs were characterized by scanning electron microscope and transmission electron microscope. Their toxicity effects were evaluated at various concentrations with the consideration of the media on the toxicity influence. All metal oxides had less influence on the survival of the entomopathogenic nematode and growth of the nematode symbiotic bacterial partner in a concentration dependant manner NPs. The observed toxicity was in the order of Fe3O4 < TiO2 < ZnO NPs respectively, with no significant difference between the NPs. The less toxic effect of the NPs noted may be associated with the ability of entomopathogenic nematodes and their bacterial partner to tolerate toxicants. Nonetheless, other toxicity parameter of NPs on the beneficial nematodes needs to be evaluated for consideration of the compatibility potential of the nematodes and NPs for pest management.

Influence of Metal Oxides Nanoparticles on Pathogenicity of Steinernema carpocapsae Nematodes Against Lepidopteran Galleria mellonella.

Entomopathogenic nematodes (EPNs) have been cited as a safe and effective method for pest management. Their virulence against lepidopterans and other foliar pest has been demonstrated in the laboratory, but achieving field efficacy is challenged with environmental conditions such as desiccation and ultraviolet radiations. Nanoparticles (NPs) as UV-blocking agents have been reported to provide an alternative approach to enhance the EPNs efficacy. We screened the effect of ZnO, TiO2 and Fe3O4 NPs on survival and pathogenicity of EPNs, and determined whether the nanoparticles could provide protection to the EPNs at low concentrations when applied in direct sunlight. All nanoparticles had less influence on the survival of infective juveniles and did not deprive their pathogenic properties following prolonged exposure. The survival rate of nematodes decreased with increased concentrations, with no measurable difference between NPs. Moreover, the survival rate of nematodes exposed to UV radiation in different formulation decreased significantly with the increase in exposure time (p < 0.001). On the other side when EPNs in nanoparticles formulations were exposed to sunlight, their efficacy significantly improved by protecting nematodes from ultraviolet radiation when compared to the water-based formulation. Pathogenic efficacy after exposure to sunlight was in the order of ZnO > TiO2 > Fe3O4 > H2O, indicating the compatibility of nematodes and NPs, and the benefit of different NPs in EPNs formulations. General nanoparticles are novel ingredients that provide suitable protection of EPNs for management of foliar pests. However, the EPNs nanoparticles formulation under a specific agricultural system and climatic condition need to be established.

Multiple ecosystem services from field margin vegetation for ecological sustainability in agriculture: scientific evidence and knowledge gaps.

BACKGROUND: Field margin and non-crop vegetation in agricultural systems are potential ecosystem services providers because they offer semi-natural habitats for both below and above ground animal groups such as soil organisms, small mammals, birds and arthropods that are service supplying units. They are considered as a target area for enhancing farm biodiversity. METHODOLOGY: To explore the multiple potential benefits of these semi-natural habitats and to identify research trends and knowledge gaps globally, a review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 235 publications from the year 2000 to 2016 in the Scopus and Web of Science databases were reviewed. RESULTS: The literature showed an increasing trend in the number of published articles over time with European studies leading in the proportion of studies conducted, followed by North America, Asia, South America, Africa and Australia. Several functional groups of organisms were studied from field margin and non-crop vegetation around agricultural lands including natural enemies (37%), insect pests (22%), birds (17%), pollinators (16%), soil macro fauna (4%) and small mammals (4%). Ecosystem services derived from the field margin included natural pest regulation, pollination, nutrient cycling and reduced offsite erosion. Some field margin plants were reported to host detrimental crop pests, a major ecosystem dis-service, potentially leading to increased pest infestation in the field. CONCLUSION: The majority of studies revealed the importance of field margin and non-crop vegetation around arable fields in enhancing ecosystem biodiversity. Promotion of field margin plants that selectively enhance the population of beneficial organisms would support sustainable food security rather than simply boosting plant diversity. Our analyses also highlight that agro-ecological studies remain largely overlooked in some regions.

Phytochemical Analysis of Tephrosia vogelii across East Africa Reveals Three Chemotypes that Influence Its Use as a Pesticidal Plant.

Tephrosia vogelii is a plant species chemically characterized by the presence of entomotoxic rotenoids and used widely across Africa as a botanical pesticide. Phytochemical analysis was conducted to establish the presence and abundance of the bioactive principles in this species across three countries in East Africa: Tanzania, Kenya, and Malawi. Analysis of methanolic extracts of foliar parts of T. vogelii revealed the occurrence of two distinct chemotypes that were separated by the presence of rotenoids in one, and flavanones and flavones that are not bioactive against insects on the other. Specifically, chemotype 1 contained deguelin as the major rotenoid along with tephrosin, and rotenone as a minor component, while these compounds were absent from chemotype 2, which contained previously reported flavanones and flavones including obovatin-3-O-methylether. Chemotype 3 contained a combination of the chemical profiles of both chemotype 1 and 2 suggesting a chemical hybrid. Plant samples identified as chemotype 1 showed chemical consistency across seasons and altitudes, except in the wet season where a significant difference was observed for samples in Tanzania. Since farmers are unable to determine the chemical content of material available care must be taken in promoting this species for pest management without first establishing efficacy. While phytochemical analysis serves as an important tool for quality control of pesticidal plants, where analytical facilities are not available simple bioassays could be developed to enable extension staff and farmers to determine the efficacy of their plants and ensure only effective materials are adopted.