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

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

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

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

Characterization of Secondary Metabolites Responsible for the Resistance of Local Tomato Accessions to Whitefly (Bemisia tabaci, Gennadius 1889) Hemiptera in Tanzania

Plants have developed mechanisms to cope with stresses in their environments as they grow in diverse settings. Such means include releasing plant defense compounds upon attacks by pests or other stressors. Plants with these characteristics are essential as a plant germplasm source for breeding resistance against herbivores and insect pests. Therefore, this study aimed to screen germplasms for whitefly resistance and characterize the secondary metabolites responsible for this. Thirty local tomato accessions were screened for resistance against whiteflies (Bemisia tabaci Gennadius) in the screen house located at Tanzania Plant Health and Pesticides Authority (PTHPA) between January and April 2021. From this screening, seven local tomato cultivars: TZA3729, TZA5554, TZA5545, TZA5562, TZA5552, TZA3177 and TZA5157, showed resistance, and one accession (TZA5496) that showed susceptibility to whiteflies (negative control) and accession V1030462 that was a standard (positive control) were selected for the subsequent experiments. The experiment was conducted in July&ndash;October 2021 in the screen house at TPHPA and repeated in January&ndash;April 2022 using a completely randomized block design with three replications. From this experiment, three accessions: TZA3729, TZA5562 and TZA5157, showed resistance against whiteflies. However, accession TZA3729 was more resistant than TZA5562 and TZA5157 when compared to the resistant accession V1030462. Therefore, these accessions were further screened for secondary metabolites responsible for resistance against herbivores and insect pests&mdash;in this case, whiteflies. The GS-MS methanol extract results showed accession TZA3729 to possess a wide array of secondary plant metabolites responsible for plant self-defenses, such as diterpenes, Tetraterpenes, alkaloids, carotenoids and fatty acid esters. Therefore, the study recommends accession TZA3729 as a source of tomato plant germplasm for breeding tomatoes resistant to whiteflies

Farmers’ Knowledge on Whitefly Populousness among Tomato Insect Pests and Their Management Options in Tomato in Tanzania

Whitefly is a populous insect pest among tomato insect pests, causing significant crop loss through direct and indirect attacks. The current study aimed to assess the knowledge of tomato farmers on the populousness of whiteflies compared to other tomato insect pests and explore the management options available in their farming context in three tomato-growing regions, Arusha, Morogoro, and Iringa, in Tanzania. The study used a questionnaire to collect the data with backup information obtained through key informants’ interviews and focus group discussions. The study findings indicated whitefly to be populous among tomato insect pests. However, tomato farmers showed varying knowledge of whitefly aspects, including differing control options for the pest. Such findings indicated a knowledge gap between farmers’ understandings of the pest and their practices in fighting it compared to the standard and required practices in controlling the pest