Seasonal Differences in the Abundance of Tsetse Flies (Glossina Species) in Pantaki, Kaduna State

Seasonal differences in the abundance of tsetse flies in Pantaki was investigated between July and August, 2016 and January and February, 2017 in Kagarko. Standard bioconical trapping method was used to collect the insects. A total of 208 tsetse flies were caught of which 139 (66.8%) were Glossina palpalis palpalis while 69 (33.2%) were Glossina tachinoides revealing an overall apparent density of 3.7T/T/D. The results indicate a significant difference (p<0.05) in abundance of tsetse flies in the wet compared to the dry seasons. Also, both species were relatively more abundant during wet (G. palpalis palpalis 75.5%, G. tachinoides 84.1%) than dry (G. palpalis palpalis 24%, G. tachinoides 15.9%) seasons. The differences in abundance observed could be due to the favourable climatic condition. This call for deployment of tsetse fly control measures (during the wet season) in the area.

Deltamethrin Persistence on Textiles Used to Make Visual Targets for Tsetse Fly Control is Positively Correlated With Their Polyester Content

Insecticide-impregnated traps and visual targets are used for tsetse (Diptera, Glossinidae) population control. Such devices are made with textiles and deltamethrin is frequently the insecticide of choice. However, persistence of an insecticide on textiles is affected by exposure to weather. Here we examine the effect of weathering on the capacity of four textiles with increasing proportions of polyester (0, 35, 65, and 100%) with cotton and viscose to retain deltamethrin. Textiles tested were those used to make visual targets in a pan-African program to maximize target efficiency for controlling tsetse vectors of African trypanosomiasis. Following impregnation in an aqueous suspension of deltamethrin at 1,000 mg/m2, textiles were weathered for 18 mo at Lambwe Valley, Kenya and sampled every 3 mo to make knockdown tests on the tsetse fly Glossina pallidipes Austen. Deltamethrin content of the textiles was established using gas chromatography mass-spectrometry at impregnation and after 9 mo of weathering. Textiles with higher proportions of polyester retained deltamethrin better: respectively, 100% polyester and 65:35 polyester/viscose textiles retained deltamethrin at 17 and 11 mg/m2 9-mo post-treatment that caused 100% knockdown in G. pallidipes after 1 h, and killed 67 and 47% of flies, respectively, after 24 h. Eighteen-month weathered 100% polyester treated textile still knocked down all tsetse exposed to it within 2 h. The LD50 for deltamethrin on filter paper for G. pallidipes was estimated at 28.8 mg/m2, indicating that deltamethrin is more available on polyester to kill tsetse.

Comparative performance of traps in catching tsetse flies (Diptera: Glossinidae) in Tanzania

This study was conducted to determine the efficiency of different tsetse traps in 28 sites across Tanzania. The traps used were biconical, H, NGU, NZI, pyramidal, S3, mobile, and sticky panels. Stationary traps were deployed at a distance of 200 m apart and examined 72 h after deployment. The results showed that 117 (52.2%) out of the 224 traps deployed captured at least one Glossina species. A total of five Glossina species were captured, namely Glossina brevipalpis, Glossina pallidipes, Glossina swynnertoni, Glossina morsitans, and Glossina fuscipes martinii. Biconical traps caught tsetse flies in 27 sites, pyramidal in 26, sticky panel in 20, mobile in 19, S3 in 15, NGU in 7, H in 2 and NZI in 1. A total of 21 107 tsetse flies were trapped, with the most abundant species being G. swynnertoni (55.9%), followed by G. pallidipes (31.1%), G. fuscipes martinii (6.9%) and G. morsitans (6.0%). The least caught was G. brevipalpis (0.2%). The highest number of flies were caught by NGU traps (32.5%), followed by sticky panel (16%), mobile (15.4%), pyramidal (13.0%), biconical (11.3%) and S3 (10.2%). NZI traps managed to catch 0.9% of the total flies and H traps 0.7%. From this study, it can be concluded that the most efficient trap was NGU, followed by sticky panel and mobile, in that order. Therefore, for tsetse fly control programmes, NGU traps could be the better choice. Conversely, of the stationary traps, pyramidal and biconical traps captured tsetse flies in the majority of sites, covering all three ecosystems better than any other traps; therefore, they would be suitable for scouting for tsetse infestation in any given area, thus sparing the costs of making traps for each specific Glossina species.Keywords: tseste; traps; densties; Glossina; mobile; stationary; Tanzania