Browsing by Author "Madege, R.R"
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Item Farmers’ perspectives on occurrence and management of rust and groundnut leaf spot diseases in different agro-ecological zones in Mtwara Region(Sokoine University of Agriculture., 2022) Kinanda, R.I; Madege, R.R; Lyimo, H.J.FRust and leaf spot diseases are important constraints of groundnut (Arachis hypogaea L.) production in Mtwara. This study aimed at establishing farmers’ viewpoint on occurrence and management measures against foliar fungal diseases in coastal zone (CZ) and eastern plateaux and mountain block zone (EPMBZ) of the Mtwara region. Random and purposive sampling methods were employed and a 200 farmers sample size was used. Semi-structured questionnaire was administered. About 100 farms were selected and, a square quadrat was used whereby in each square, 5 plants were assessed for disease severity and incidence. Early leaf spots (ELS) had the highest incidence (93%) and severity (49%) followed by rust (79% incidence and 35% severity). The lowest incidences and severity were observed for late leaf spot (LLS) as 71% and 30%, respectively. There was a significant difference between the farmers awareness on the fungal diseases in the two zones were significantly varied (df = 198, p = 0.033) Farmers in the CZ were more aware of rust and late leaf spot diseases than those in EPMBZ. The majority of farmers in the CZ adopted appropriate disease management measures especially the removal of volunteer plants (94%) and use of conventional tillage (29%), respectively, to reduce disease inoculum from the soil surface. The study concludes that farmers in Mtwara region differentially understand the fungal foliar diseases. The occurrence and severity of rust, ELS and LLS varied between locations suggesting there is environmental influence. Meanwhile, farmers in CZ and EPMBZ employed different disease management agricultural practices that they did not employ/adopt the use of chemical fungicides. The study recommend intercropping groundnuts with tubers and legumes, usage of certified seeds, management of crop residues, removal of volunteer plants before sowing and conventional tillage as means of rust and leaf spot diseases management options to increase groundnut yield in the Mtwara region.Item Natural occurrence of moulds and mycotoxins in Synadenium Glaucescens Extracts (SGE) under different storage conditions(TAJAS, 2022) Mabiki, F.P; Madege, R.RFungal growth and mycotoxin contamination in value-added medicinal plants products are quality and safety attributes that negatively affect entry to the market. This research aimed at investigating the occurrence of spoilage fungi and mycotoxins in Synadenium glaucescens extracts (SGE) from different plant parts and storage conditions. Laboratory whole water extraction method was used to prepare SGE from root-wood, root bark, leave, stem-bark and stem-wood. SGEs were subjected to storage temperature (25°C and 4°C refrigeration) and light (light and dark) conditions for 21 days. Samples were evaluated weekly to enumerate the occurrence of spoilage fungi and identified. In a follow-up experiment, pure cultures of Fusarium moniliforme and Aspergillus flavus were inoculated in SGEs and incubated for 14 days to allow production of mycotoxins. Aflatoxin and fumonisins were quantified using LC-MS/MS. It was established that 70% of samples of SGE contained Fusarium moniliforme and 60% Rhizopus spp. SGE samples stored under full light illumination were spoiled by Rhizopus species (35%), F. moniliforme (30%), F. pallidoroseum (3%), Cladosporium leguminicola (5%), C. sphaerospermum (2%), Alternaria alternate (6%) and Curvularia lunata (4%). The highest isolation frequency of F. moniliforme was in SGE from root wood (42%) and stem (42%). The highest (38%) isolation frequency of Rhizopus sp. was in SGEs from stem wood followed by root bark (32%) and 30% in both stem and root. Aflatoxin B1 was not detected in any sample. Fumonisin B1 (FB1) was detected in 80% of the samples and the concentration varied from 0.01μg/Kg to 6.33 μg/Kg. Among the samples contaminated with FB1, SGEs made from roots were contaminated by FB1 in a range of 0.03 to 0.04 μg/Kg, stem wood from 1.52 to 6.33 μg/Kg while in the root bark varied from 0.01 to 1.83 μg/Kg. SGE made from stem bark had FB1 ranging from 1.03 to 4.04 μg/Kg. Since fungal contamination was noted after 21 days of incubation, the source of spoilage fungi could be from the environment during postharvest handling. Therefore, it can be recommended that SGE safety can be ensured if good manufacturing practices (GMP) are maintained during preparation. Moreover, the Leaf SGEs were less vulnerable to fungal growth and fumonisin contamination at room temperature. Therefore, where the efficacy is the same, the leaf of S. glaucescens is possibly a better source of SGE formulations. These findings provide a benchmark of future investigations for more innovative GMP and safety measures to protect consumers against risks of exposure to mycotoxins.Item Pathogenicity of pyricularia oryzae isolates obtained from cultivars grown in middle and high altitudes zones of Burundi(An International Journal of Basic and Applied Research, 2022) Niyonkuru, E; Madege, R.R; Bigirimana, J; Habarugira, G.Rice blast disease caused by the fungal pathogen called Pyricularia oryzae is an economically important disease distributed in rice-growing regions of the world. Understanding pathogenic variation among isolates paves a way towards the most effective ways to manage the disease. Thirteen isolates of P. oryzae from high and middle altitude rice ecosystems were inoculated into ten (10) cultivars most preferred by rice farmers in the middle and high-altitude areas of Burundi. The isolates were then evaluated for their ability to cause rice blast disease under screen house condition. A complete randomized design (CRD) with three replications was used. The tested cultivars were evaluated as susceptible(S) or resistant (R) to a particular P. oryzae isolate based on disease severity score determined through visual observation using a standard 0-9 scale developed by IRRI. Highly significant differences (p=0.000) between location were observed in rice blast disease incidence and severity. Significant differences (p=0.000) in blast incidence and severity were recorded between cultivars as well as isolate. Disease incidence and severity in the cultivars ranged from 11.11-33.33% and 3.70-69.14% respectively. Despite this variability in the isolate pathogenicity, three rice cultivars (Mugwiza, Rufutamadeni and V18) were less susceptible to the disease and hence can be regarded as having traits of resistance which can be used by rice farmers for managing rice blast disease in the two rice ecosystems of Burundi but also as parent materials for development of rice cultivars with resistance to rice blast.Item Relationship between plant parasitic nematodes, arbuscular mycorrhizal fungi and soil characteristics on clove (syzygium aromaticum (l.) merr and perr) agroecosystem in east Usambara mountains-Tanzania(TAJAS, 2022) Machera, S; Madege, R.R; Njau, P; Nzogela, Y.Native communities of arbuscular mycorrhizal fungi (AMF) and plant parasitic nematodes (PPN) were examined in fields previously under climate-smart agriculture (CSA) and non-climate smart (NCSA) of the East Usambara Mountains. The field were differing in soil properties and agricultural practices. Soil samples were taken from 10 sites in each of the 30 fields. AMF spores and PPN were isolated using wet- sieving method and the Baermann tray method, respectively. The isolated fungal spores and PPN were morphologically identified, classified and quantified. A total of 10 AMF and 27 PPN genus were recorded. The CSA and NCSA fields had 51% and 56% of genus Glomus, respectively. About 73.2% and 72% of genus Rotylenchulus were recovered in CSA and NCSA, respectively. No association was found between AMF and PPN, a significant correlation between PPN and AMF abundance with agricultural practices was observed (p=0.001). No significant difference was found between AMF (p=0.8) and PPN communities (p=0.6) with agriculture practices. Correlating AMF and PPN with soil properties showed no association and no significant difference except for PPN with total nitrogen (p=0.03). Whatever the causes of no significant difference between the treatments,the results suort that CSA practices can facilitate mycorrhizal colonization.. Our results showed that both agriculture practices didnot influence AMF and PPN abundance in the soil.