Life sciences and Bio-engineering
https://dspace.nm-aist.ac.tz/handle/20.500.12479/2
2024-03-28T20:03:59ZSurvival Mechanisms and Management Challenges Associated with Silver Leaf Whitefly on Tomato in Africa: A Review
https://dspace.nm-aist.ac.tz/handle/20.500.12479/2508
Survival Mechanisms and Management Challenges Associated with Silver Leaf Whitefly on Tomato in Africa: A Review
Mrosso, Secilia; Ndakidemi, Patricka; Mbega, Ernest
Silver leaf whitefly (Bemisia tabaci Gennadius) (Hemiptera: Aleyrodidae) is a polyphagous winged insect pest that causes high yield losses in tomatoes and other vegetable crops globally. To combat the infestation by the silver leaf whitefly and other insects, tomato growers use cultural and synthetic chemical-based methods. However, the silver leaf whitefly continues to dominate the tomato production systems. Some of the reasons for such continued dominion by the silver leaf whitefly in tomato include among other reasons; little understanding of the mechanisms for survival of the insect pest by tomato production stakeholders which consequently results in difficulties in making appropriate pest management decisions, presence of diverse hosts, the ability of the silver leaf whitefly to develop resistance to synthetic pesticides and ineffective techniques used by tomato grower in combating the insect. Of these challenges, this review discusses the mechanisms for survival of the insect, current pest management options and recommendations for a way forward concerning the silver leaf whitefly management in Africa.
A research article was published by International Journal of Agriculture & Biology Volume 27, 2022
2022-04-30T00:00:00ZThe Effect of Field Margin Plants with Pesticide Properties on Growth and Yield of Lablab
https://dspace.nm-aist.ac.tz/handle/20.500.12479/2507
The Effect of Field Margin Plants with Pesticide Properties on Growth and Yield of Lablab
Lyatuu, Emanuel; Mbega, Ernest
Lablab crop is an essential pulse, cum vegetable, and is more adapted to different environmental conditions than
any other legume. Like other crops, it is infested by insect pests. The specific objective was to assess the effect of field
margin plants with pesticide properties on growth and yield of lablab. Lablab seeds, tephrosia vogelii powders and field
margin plants (Ocimum, Hyptis and Sphaeranthus) were used in this study. The experimental field was tilled, then the plots
of 10m x 10m were established at the distance of 20m apart and randomized complete block design (CRBD) with three
replications was used to assign treatment in each plot. The growth components plant heights (H) and the number of leaves
per plant were measured on the 4th, 8th and 12th weeks after germination while the yields was measured after harvest and
threshing. The study findings demonstrated effectiveness of field margin plants with pesticide properties at the edge in
reducing pest incidents by attracting more natural enemies on 4th week found 3 spiders and no insect pest compared to
other treatments, and reduce severity of foliage damage as well as increasing lablab yields (129.84kg/ha) compared to those
with no field margin pesticidal plants which yielded 115.49kg/ha, hence higher yields on plots with field margin pesticidal
plants in combination with application of fish bean [Tephrosia vogelii] which yielded 222.70kg/ha. Hence, the use of field
margins with desired pesticide properties offer a sustainable way to increase yield.
A research article was published by International Journal of Environmental Science Volume 8, 2023
2023-09-19T00:00:00ZMathematical model to assess the impacts of aflatoxin contamination in crops, livestock and humans
https://dspace.nm-aist.ac.tz/handle/20.500.12479/2506
Mathematical model to assess the impacts of aflatoxin contamination in crops, livestock and humans
Mgandu, Filimon; Nyerere, Nkuba; Mbega, Ernest; Chirove, Faraimunashe; Mirau, Silas
Aflatoxin contamination poses a significant challenge in food safety and security as it affects
both the health of consumers and supply chains. Due to the health impacts associated with
aflatoxin contamination, countries have set standards and restrictions for importing food
crops and animal feed, resulting in greater economic losses to farmers, transporters, and crop
processors. This study aimed to develop a mathematical model that tracks the contamination
status of crops, livestock and humans in supporting efforts to control aflatoxin. The analysis
of the mathematical model shows that both aflatoxin contamination-free equilibrium (ACFE)
and aflatoxin contamination-persistence equilibrium (ACPE) exist. To study the dynamics of
contamination, we derived the basic aflatoxin contamination number, 𝑅0 which is analogous
to the basic reproduction number in epidemiological models. When 𝑅0 < 1, the ACFE is
globally asymptotically stable, whereas when 𝑅0 > 1 the ACPE is globally asymptotically stable.
Partial Rank Correlation Coefficients (PRCCs) for global sensitivity analysis were calculated
using Latin Hypercube Sampling (LHS) to see how sensitive and significant the parameter is on
each variable. Results from numerical simulations showed that decreasing crop contamination
and shading rates and increasing the death rate of aflatoxin fungi in soil by 50% can reduce
the basic contamination number by above 92%. Thus, it is important to introduce control
measures that target crop contamination, shading and death rates of aflatoxin fungi in soil to
reduce contamination in the population. Compared to other studies in aflatoxin contamination,
the current study provides a thoroughly global sensitivity analysis of parameters involved in
contamination and indicated the most important ones for control strategies
A research article was published by Scientific African Volume 23, March 2024
2024-03-01T00:00:00ZAssessment of physical chemical parameters of cashew apples from selected cashew varieties grown in Tanzania
https://dspace.nm-aist.ac.tz/handle/20.500.12479/2503
Assessment of physical chemical parameters of cashew apples from selected cashew varieties grown in Tanzania
Msoka, Regina
Cashew apple fruits are deserted by majority of cashew nuts producers despite of being rich in useful nutrients namely vitamins, minerals and sugar. This study was carried out to determine the physico-chemical parameters of five cashew apple varieties from Mtwara and Lindi regions in south-eastern part and Coast region in eastern part of Tanzania. Cashew apple varieties named Brazilian dwarf (B.D), Anacardium Ceylon 4 (AC4), Anacardium Ceylon 10 (AC10), Anacardium Zanzibar 2 (AZA2) and Anacardium Zanzibar 17 (AZA17) were selected and analysed for vitamin C, carotenoids, total sugar, total phenolic content (TPC), minerals, pH, total soluble solids (TSS) and total titratable acidity (TTA) using standard methods and procedures. Significant difference (p < 0.05) was observed in vitamin C, total sugar, TPC, TSS and TTA between the five varieties and sites with the content ranging from; vitamin C (253.09 - 348.54 mg/100 ml), total sugar (88.7 – 219.4 g/L), TPC (1066.55 – 2886.67 mg/L GAE), TSS (14.94 - 20.36 °Brix) and TTA (0.18 - 0.72%). Other parameters, pH and carotenoids differed significantly between varieties (p < 0.001) but there was no significant difference observed between sites. Minerals (Ca2+, K+ , Mg2+, Na+ , P3˗ , Fe2+ , Zn2+ and Cu2+) content differed significantly between varieties and sites (p < 0.05), except for calcium, magnesium and sodium. In Chambezi- Bagamoyo site, varieties differed significantly in all the parameters analysed except for vitamin C, pH, total soluble solids and all the minerals analysed except Ca2+ . These results have availed the potential nutritional value of locally available cashew apple fruits to food and nutrition security if well promoted for utilization.
A dissertation submitted in partial fulfillment of the requirements for the degree of master’s in life science of the nelson Mandela African institution of science and technology
2017-12-01T00:00:00Z