Status and Management of Cashew Disease in Tanzania

Cashew (Anacardium occidentale L.)is one of the most important export cropsand the main source of cash income in the southern part of Tanzania. However it is challenged by a number of factors such as drought, declining soil fertility, un-improved low yielding cashew genotypes, insect pests and diseases. Of these factors, diseases have been cited to result in high production costs, poor nut quality and low market price. The most devastating diseases that attack cashew are powdery mildew, cashew leaf and nut blight, dieback and fusarium wilt.Other minor diseasesinclude anthracnose, damping off and leaf spots.Despite the negative role that these diseases possess to cashew growers, there is limited or no critical updated information on their current infection status and management in Tanzania. Thus, this review articlediscusses the status of the most important cashew diseases and their management options in the country. Such informationwill be vital to cashewfarmers and other stakeholdersin making appropriate improvements in cashew production in Tanzania

Prospects of Using Termite Mound Soil Organic Amendment for Enhancing Soil Nutrition in Southern Africa

This research article published by MDPI, 2020Termite mound soils are reportedly utilized as an alternative to NPK fertilizers by cash constrained smallholder farmers in some parts of Southern Africa. However, there is limited knowledge regarding their mineral nutritional value. The intention of this work was therefore to investigate 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 36 sites across Pemba and Choma districts in Southern Zambia through collection of soil samples in triplicate at 0–20 cm depth, using a soil auger. Findings revealed that the soil pH had elevated levels in the base segments of the termite mounds compared with the top and the neighbouring soils. However, elevated N, P and K levels were recorded in the top sections with significant differences (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. We concluded that top termite mound soil should be considered as part of an integrated nutrient management strategy by financially challenged smallholder farmers cultivating in light textured soils of southern Africa

Potential of Indigenous Pesticidal Plants in the Control of Field and Post-Harvest Arthropod Pests in Bambara Groundnuts (Vigna subterranea (L.) Verdc.) in Africa: A Review

This research article published by Scientific Research Publishing Inc., 2020Bambara groundnuts (Vigna subterranea (L.) Verdc.) is an important leguminous crop native in Africa and is mainly cultivated for its highly nutritious grains. However, bambara groundnuts production is constrained by many insect pests including aphids (Aphids sp.), leaf hopers (Hilda patruelis), foliage beetles (Ootheca mutabilis), pod sucking bugs (Clavigralla tomentosicollis), red spider mites (Tetrunychus sp.), groundnut jassids in the field and bruchids (Callosobruchus maculatus, and Callosobruchus subinnotatus) in the storage. Smallholder farmers usually apply synthetic pesticides to control those insect pests. However, synthetic pesticides are potentially harmful to the environment, non-targeted animals and human’s health. Pesticidal plants such as B. pilosa, L. camara, T. vogelii, V. amygdalina, L. javanica, T. diversifolia, and C. dichogamus which are available in most parts of Africa where the crop is cultivated, possess bioactive chemicals which have insecticidal properties and have been revealed to be potential in the control of field and storage insect pests. Therefore, they can be used as an alternative to synthetic pesticides. Bambara groundnuts being one of the neglected crops, the insects affecting the crop have not been well explored in terms of their abundance and damage they cause to the crop in the field and on storage. Thus, in this review, the common arthropod pests of the bambara groundnuts and the potential of the bioactive compounds from the common plants with pesticidal properties have been described. It is recommended that the potential of these pesticidal plants to be investigated on bambara groundnut pests control on the field and on storage to optimize their use by smallholder farmers in insect control to reduce dependence on synthetic pesticides

Fall armyworm infestation and management practices on maize fields of smallholder farmers in Northern Tanzania

This research article published by the Journal of Biodiversity and Environmental Sciences (JBES), 2019Fall armyworm (FAW) is native to America and is currently affecting maize production in different parts of Africa, and recently reported in Tanzania. In the present study, FAW infestation levels and their associated management practices were investigated in 90 maize fields in the 18 villages in Arusha, Kilimanjaro and Manyara regions. Infestation levels were assessed using a scale of 0 (no damage) to 9 (100% damage), while the management practices information was collected through a survey and questionnaires from 210 maize growing farmers in the 18 villages. Results showed that all fields were infested by FAW at low (1-4) to moderate (5-7) damage levels. Arusha scored the highest (66.59% and 5.422) significant mean incidence and severity (P<0.05) respectively, followed by Kilimanjaro (52.96%, 4.756) and Manyara (52.64%, 3.989) regions. Variation in damage levels was also observed among villages, with means incidences ranging between 35.57% and 79.55%, and mean severity ranging between 2.333 and 7.267. Variation between regions and villages can be associated with farmer’s knowledge and FAW management practices. About 84.3% of farmers reported synthetic pesticides as the main management option, although the majority did not effectively apply them. Farmer’s recommendations include awareness creation on the FAW management, provision of effective pesticides and resistant maize varieties, and government intervention in the overall management of FAW. From the findings it is evident that sustainable integrated management strategies against FAW is urgent needed and this study serves as a stepping stone for the development of sustainable management options

Botanical extracts control the fungal pathogen Colletotrichum boninense in smallholder production of common bean

Anthracnose caused by Colletotrichum spp. remains an intractable problem in the most common bean (Phaseolus vulgaris) production areas worldwide and can cause total yield loss. Many smallholder farmers are familiar with using botanical extracts to control insect pests; however, there is less familiarity with their use to control fungal diseases due to a lack of evidence. Here, we demonstrate that anthracnose could be controlled effectively by pesticidal plant species that are used for insect control. In laboratory trials, water extracts from 11 plant species could inhibit fungal growth (100%) and spore germination (75–100%) equally well to two commercially available fungicides, the synthetic Mancolaxyl and biofungicide Bioderma. In screenhouse trials, anthracnose disease was reduced by the extracts of three plant species. Moreover, bean crop growth in these botanical treatments did not differ significantly from that observed in the commercial fungicide treated plants. Field trials in a smallholder community reporting severe problems with anthracnose showed an effect similar to the screenhouse results. Field trials resulted in bean seed yields approximately 350 kg/ha higher in bean plants treated with Azadirachta indica and Lippia javanica at 10% w/v compared to the negative control untreated plants. In all trials, botanical extracts were as effective as commercially available fungicides, suggesting that these botanical extracts could provide dual-purpose pest and disease management for anthracnose and crop pest insects. The outcomes of this research show that prospects for using locally available resources to control anthracnose on common bean are credible and can be combined with controlling insect pests

Mechanisms for salmonella infection and potential management options in chicken

This research article published by The Journal of Animal & Plant Sciences, 2020Salmonella enterica is the largest species in genus Salmonella with its serovars responsible for infection in chickens and other warm-blooded hosts. After oral ingestion, Salmonella penetrates the mucosal layer of the gastrointestinal tract (GIT). It then provokes gastroenteritis and systemic infection to chickens of all ages depending on the serovar involved. The paper explains about Salmonella infection via Type Three Secretion System (TTSS) encoded Pathogenicity Islands (PIs) and how the bacterium survives the acidic environment of GIT. It also explains the roles of TTSS-1 and TTSS-2 in translocation of effectors that interfere with host proteins and later internalisation of Salmonella in Salmonella- containing vacuole (SCV). Other virulence factors such as plasmid, biofilm and lipopolysaccharides are highlighted, and their importance in inducing pathogenicity to host was also included in the paper. Therefore, several factors are geared toward survival, infection, and replication of Salmonella in the host cells. Hence, this article explains the mechanisms of Salmonella infection in chicken, its persistence in different environments and the approaches in controlling chicken salmonellosis

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

This research article published by the American Society for Microbiology, 2020We present here the complete genome sequences of plant growth-promoting sp. strain MPUS7, sp. strain NGAS9, and sp. strain LUTT5, isolated from rhizosphere soils and tubers of potato ( L.) plants growing in the northern and southern highlands of Tanzania

Field margin plants support natural enemies in sub-Saharan Africa smallholder common bean farming systems

Flower-rich field margins provide habitat 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, 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 NEs 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; lacewings with T. minuta and B. pilosa margins. Overall, NEs 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 Nanoparticles of Metal Oxides on the Survival of the Entomopathogenic Nematode: .

This research article published by Ingenta, 2020Nanoparticles (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 (), as well as their growth inhibition effects on the nematode symbiotic bacteria (). 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

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 inves-tigated 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, pred-atory 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 mar-gin 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 intercrop-ping than in monocropping although the effect was not significant in both low and high plant di-versity fields. We recommend smallholder farmers protect the field margins for the added benefit of natural pest regulation in their fields