Department of Medical Parasitology, School of Medicine, Catholic University of Health and Allied Sciences-Bugando, P.O. Box 1464, Mwanza, Tanzania.
SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3297, Chuo Kikuu, Morogoro, Tanzania.
Malar J. 2019 Jul 8;18(1):226. doi: 10.1186/s12936-019-2861-4.
The wide distribution of malaria mosquito breeding sites within tropical environments limits the mosquito larval source management efforts to control malaria. Rice farming contributes substantially in supporting malaria mosquito productivity in tropical countries. To overcome this challenge, this study was carried out to determine the effect of applying a mixture of biolarvicide and fertilizer on mosquito larvae density in rice farms under semi-field conditions in Tanzania.
A semi-field experiment was designed to determine the timing of application of a biolarvicide, Bacillus thuringiensis israelensis (Bti) and fertilizer (di-ammonium phosphate-DAP or urea) and assess their effect on mosquito larvae density and rice grain outputs. The experiment had five blocks (4 treatment arms and one control arm) and each had four replicates. Treatment arms had different intervals of days between treatments for mixtures of fertilizer and biolarvicides. The dosages used were 10 g of Bti/16 M and 160 g of DAP/Urea/16 m.
In overall, the intervention blocks (with biolarvicide) had lowest mean mosquito larvae abundance compared to control block (F = 22.42, P < 0.001). Similarly, the control arm maintained highest density of Anopheles gambiae sensu lato larvae compared to interventions blocks (F = 21.6, P < 0.001). The best determined timing for application of Bti was in 7 and in 10 days (F = 3.753, P < 0.001). There was neither significant different in mean rice grain harvest per ten panicle (F = 1.453, P = 0.27) nor mean difference in rice grain harvest (F = 1.479, P = 0.26) per intervention arms.
The findings of this study have shown that application of a mixture of Bti and fertilizer have impact on both mosquito larvae density and maintaining yield rice harvest. Thus, application of a combination of biolarvicide and fertilizer can be an alternative approach in malaria mosquito intervention among rice farming communities of rural Tanzania.
疟疾蚊子滋生地在热带环境中的广泛分布限制了蚊幼源管理工作来控制疟疾。水稻种植在热带国家对支持疟疾蚊子的生产力做出了巨大贡献。为了克服这一挑战，本研究旨在确定在坦桑尼亚半野外条件下，应用混合生物杀虫剂和肥料对稻田中蚊子幼虫密度的影响。
设计了半野外实验，以确定生物杀虫剂苏云金芽孢杆菌以色列亚种（Bti）和肥料（磷酸二铵-DAP 或尿素）的应用时间，并评估它们对蚊子幼虫密度和水稻产量的影响。实验有五个块（4 个处理臂和 1 个对照臂），每个块有 4 个重复。处理臂在肥料和生物杀虫剂混合物之间的处理间隔天数不同。使用的剂量为 10g Bti/16M 和 160g DAP/Urea/16m。
总体而言，干预块（含生物杀虫剂）的蚊子幼虫丰度均值最低，与对照块相比差异有统计学意义（F=22.42，P<0.001）。同样，对照臂保持最高密度的冈比亚按蚊幼虫，与干预块相比差异有统计学意义（F=21.6，P<0.001）。Bti 最佳应用时间是 7 天和 10 天（F=3.753，P<0.001）。Bti 处理臂之间的每十个稻穗的平均水稻产量（F=1.453，P=0.27）和平均水稻产量（F=1.479，P=0.26）均无显著差异。
本研究结果表明，应用 Bti 和肥料的混合物对蚊子幼虫密度和保持水稻产量都有影响。因此，在坦桑尼亚农村水稻种植社区中，应用生物杀虫剂和肥料的组合可以作为一种替代疟疾蚊子干预的方法。
