Browsing by Author "Ndossi, Humphrey"

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Susceptibility of different species of ticks (Acari: Ixodidae) to an entomopathogenic fungus in Tanzania
(Sci Forschen, 2020-06-06) Zekeya, Never; Mbega, Ernest; Ndossi, Humphrey
Ticks and tick-borne disease cause severe skin damage on livestock as well as wildlife mortifying animal health and byproduct for processing and tourism industries. Management of ticks by conventional acaricidal is environmentally and economically unaffordable in Tanzania. This study evaluated the effectiveness of a novel entomopathogenic fungi Aspergillus oryzae (TZ/P/2018/000035) against three species of ticks (Acari: Ioxididae); Rhipicephalus appendiculatus, Hyalomma anatolicum and Amblyomma gemma by spraying 0.2 mL/tick of 1 × 106, 1 × 107, 1 × 108 conidia/ mL of A. oryzae and control (water and 0.5% triton x-100) in 35.5°C and 85% RH repeated at 20.5°C and 70% RH in the laboratory conditions at Nelson Mandela African Institution of Science and Technology, Arusha. Results showed that at 1 × 108 conidial/mL, A. oryzae caused high mortality rate averaging 88.2%, 72.5% and 67.9% within 6.25 ± 0.75 days, 7.55 ± 0.59 days and 11.9 ± 0.65 days in H. anatolicum R. appendiculatus and A. gemma respectively, whereas in control the highest mortality rate reached 12.5%, 11.0% and 6.5% after 22.50 ± 1.2, 24.6 ± 0.9 and 28 ± 2.9 days in R. appendiculatus, H. anatolicum and A. gemma respectively at 20.5°C and 70% RH. It was also revealed that at 1 × 108 conidial/mL of A. oryzae reduced oviposition rate in A. gemma whereby 94.8 ± 10.74 eggs/female were laid compared to control that laid 354.15 ± 42.65 egg/female. Again, eggs averaging 166.20 ± 7.5 eggs/female were laid in H. anatolicum treated with A. oryzae at 1.0 × 108 conidia/mL compared to control that laid eggs averaging 416.25 ± 21.71/female in cold. This study revealed that A. oryzae was effective for control of ticks could be applied in agricultural fields to protect animal from tick’s damage consequently improving animal products in processing industry in Tanzania
Understanding factors influencing distribution and density of a micro-Lepidoptera moth, Tuta absoluta (Gelechiidae) and its impact in tomato agroecological zones of Tanzania
(Bioscience Research, 2020-06-07) Zekeya, Never; Ouma, Johnson; Chacha, Musa; Ndossi, Humphrey; Mbega, Ernest
Field survey was conducted from August to November 2016 and repeated from January to April 2017 to study population, distribution and damage by tomato leaf miner (TLM) (Tuta absoluta Meyrick 1977) in 156 farms in agroecological zones of Tanzania. A pheromone trap/farm was deployed in tomato or other Solanaceae’s crops for examining moth of T. absoluta stuck in each trap and to determine damage by TLM. Results indicated that TLM is present in 13 regions with the highest population in Southern zone (Iringa), Northern zone (Arusha) and East-Central (Morogoro) with catches averaging 357.8±25.5, 279.9±12.1, 298.7±11.4 and 173.1±10.1 moths/trap in dry season respectively whereas lowest count amounting 13.3±1.0moths/trap was observed in western zone (Mwanza) during rainy season. Tomato was the most damaged crop with high mines averaging 90.0 ± 0.0% damage in Iringa and the low of 30.0±5.7 % realized in Mwanza. Tuta absoluta was found attacking 10 more plant species besides tomato with damage incidence averaging 83.3 ± 3.7% in Solanum lycopersicum, 60.0±0.0% in Solanum tuberosum, 30.0±0.0% damage in weed (Solanum incanum) and the lowest damage averaging 0.0±0.0% was observed in capsicum annuum. Based on these findings, it is evident that, T. absoluta is expanding its geographical range and hosts resulting into high damage and yield loss affecting farmers’ livelihood in Tanzania. This study informs farmers on the proper use of pheromone traps for early detection, scouting, weeding, crop rotation, use of biological control agents for effective management of the pest to reduce losses and environmental impact due to extensive use of synthetic pesticides.