Browsing by Author "Maerere, Amon P."

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Establishment of the Causal Agent(s) of Spike Shedding and Stem Wilting of Pepper (Piper nigrum L.) in Morogoro District, Tanzania
(Hindawi, 2020-11-09) Shango, Abdul J.; Majubwa, Ramadhani O.; Maerere, Amon P.
Pepper (Piper nigrum L.) serves as a source of income to smallholder spice farmers in Morogoro district of Tanzania. Recently, spike shedding and stem wilting of pepper plants were reported to cause about 30% yield loss of the crop. This study was undertaken to identify the causal agent(s) of the problems. Three pepper gardens in each of the four hamlets (Nyange, Doga, Tandai, and Lukenge) in Tandai village (Kinole ward) were surveyed, and plant tissue and soil samples were collected for laboratory analysis. An experiment was laid out in a randomized complete block design with three replications. Pepper cultivars, Babu kubwa, Babu ndogo, Babu kati, and Ismailia grown in the study area, were used as treatments for evaluation of the prevalence of spike shedding and stem wilting. Treatments mean separation was conducted based on Duncan’s multiple range test at p � 0.05. Regression (R 2 ) and simple correlation (r) analyses between stem wilting (incidence and severity) and termite pest infestation were performed. The identified pathogen in most of the soil and plant tissue samples was Fusarium oxysporum. The nutrients, N, P, Mg, and Cu, concentration in soil and leaf samples was below the optimal ranges. Termite attacks were significantly high in some farmer’s gardens where up to 50.5% of the pepper plants was damaged. Hence, a significant positive correlation was observed between termite pest infestation in gardens and both incidence (r � 0.881, R 2 � 0.74, p < 0.001) and severity of stem wilting (r � 0.918, R 2 � 0.84, p < 0.001) of pepper plants. Most of the termite attacks and damages (70%) were observed on pepper plants supported on silver oak, unlike those trained on Jatropha. A higher percentage of undeveloped berries (36%) and intermediate- size berries (34%) was recorded on cultivars “Babu kati” and “Babu kubwa,” respectively. Multiple factors have been associated to be the causes of spike shedding and stem wilting of pepper, which could be used to develop appropriate control solutions useful to farmers. Confirmation of F. oxysporum pathogenicity is recommended. A comprehensive study is suggested on the repellent or lethal activities of Jatropha against F. oxysporum and termites. Furthermore, studies through field experiments are needed to generate site-specific soil nutrient improvement recommendations and design an integrated approach to control F. oxysporum and termites and to determine existing alternative host plants for these pests.
Pre- and postharvest factors affecting quality and safety of Pepper (Piper nigrum L.)
(CAB International, 2021-03) Shango, Abdul J.; Mkojera, Beatha T.; Majubwa, Ramadhani O.; Mamiro, Delphina P.; Maerere, Amon P.
The quality and safety of pepper (Piper nigrum L.) are a function of crop management practices, harvest maturity, harvesting methods and subsequent handling after harvest, including storage conditions and processing methods. The review shows that volatile oil decreases with shade intensity (15–30%). Essential oil, oleoresin, piperine and monoterpenes (thujene, α-pinene, sabinene, limonene, α-phellandrene and linalool) increase with altitude, while β-caryophyllene and total phenol decrease with increase in altitude. Fermentation of ripe pepper fruits forms odorants (butanoic acid, 3-methylindole, and 4-methylphenol) attributing intense faecal/shed-like off-flavour white pepper powder. Low-drying temperature (≤56°C) and duration (≤3 hrs) lead to low bulk density (0.17 g/ml) and low moisture loss (31%). Excessive soaking of black peppercorns prior to mechanical decortication reduces volatile oil and increases moisture content and broken berries. Availability of heavy metals in grinding machines increases the level of heavy metals; Fe (69.8– 1147 mg/kg), Pb (21.3–947 μg/kg) and V (64.1–1072 μg/kg) in pepper powder. Storing peppercorns along with other materials enhances cross-contamination of heavy metals; Pb, Cd and Cr. High moisture content (>13%) and farmers’ unawareness resulted in high (2200 to >30000 cfu/g) mycotoxins contamination. Environmental and industrial pollutants such as plasticizers, bisphenol A, polycyclic aromatic hydrocarbons and pesticides are also pepper contaminants of high merit. Radiofrequency pasteurization, vacuum-assisted steaming, ethylene oxide fumigation, atmospheric pressure plasma, dry heat sterilization, gamma-irradiation and ultraviolet-C light treatments are among strategies to enhance the quality and safety of pepper. More precautions also have to be taken to regulate the shade, drying temperature and duration, soaking duration, hygienic processing and storage in order to retain quality, minimize the risk of microbial or chemical contaminations and comply with standards.