RJCES Volume 1 [5] December 2013 www.aelsindia.com 89 | P age Experimental Study on the Efficacy and Persistence of Deltamethrin1%, Pour-on (Smash) for the Control of Tsetse Flies in the Southern Rift Valley of Ethiopia Alemu Aylate Ayano 1 *, Tekle Olbamo 2 and Berisha Kapitano 3 1 School of Veterinary Medicine, Wolaita Sodo University, Wolaita Sodo, Ethiopia 2 School of Veterinary Medicine, Wollo University, Dessie, Ethiopia 3 Tsetse Eradication Project Coordination office, Addis Ababa, Ethiopia ABSTRACT Different technologies have been introduced and applied practically in the field for many years for the control of tsetse flies. The present study was conducted to test the efficacy and persistence of deltamethrin 1% pour-on against tsetse flies on six experimental animals. Among these animals three were poured-on with the insecticide and the rest three kept without insecticide. Deltamethrin 1% pour-on was applied on experimental animals on the middle backline from shoulder to the base of tail using T-bar applicator, according to the manufacturers’ recommended dose. The knockdown effects of the insecticide were observed at 5’, 10’ and 15’ for seven consecutive weeks. Experimental sites (middle back, belly, leg and neck) of both experimental and control groups were identified and marked with ink. The knockdown effects of the insecticide were checked weekly for seven consecutive weeks. A total of 1,800 test insects were used for the bioassay excluding weak flies. The average knockdown effect of the insecticide at 5’, 10’ and 15’ were 41%, 39% and 21% respectively in the week one and 33%, 36%, and 31% at 5’, 10’ and 15’ respectively in week two. The highest knockdown effect was recorded at 5’ of exposure (46%) in week three, followed by 31% at 15’ and 23% at 10’ of exposure. The proportion of knockdown of the flies in week 4 was 18%, 36% and 46%. In week five, 20%, 52% and 28% of flies have been knockdown at 5’, 10’ and 15’ of exposure. The proportion of knock down of flies in week 6, were 18%, 42% and 39% at 5’, 10’ and 15’ of exposure respectively. With regard to week seven, almost no flies of the experimental group have been knocked down except one on the neck at 15’ of exposure. It was observed that deltamethrin 1% pour-on uniformly spread and covered the entire body of the animal within few hours of application and no adverse effect was detected over the period of the experiment. The present study demonstrated that deltamethrin 1% Sc, pour-on is very effective at the dose rate and time interval recommended by manufacturers’ in knocking down of tsetse flies attempting to feed blood meal from animals treated with the insecticide. Key words: Deltamethrin, Efficacy, Persistence, Pour-on, Tsetse. Received 27/09/2013 Accepted 10/11/2013 © 2013 AELS, India INTRODUCTION Trypanosomiasis continues to remain a major constraint to livestock and agricultural production and consequently human health. The impact of animal trypanosomosis is mainly attributed to morbidity and mortality of livestock, treatment as well as control costs, and denied access to land resources and more importantly draught power to cultivate land for food crops. In addition, pregnant cows abort, oxen could not plough, equines could not be used for transportation, milking cows reduce milk production, and the death of animals that are not properly treated [1]. Tsetse transmitted trypanosomiasis poses a serious threat to the lives and livelihood of entire communities affecting about 300 million people in the 37 countries of sub Saharan Africa, with 55 million of them at the risk of catching the diseases. WHO has reported an estimated number of 500,000 people already infected with sleeping sickness and about 50,000 died every year. The situation is deteriorating as increasingly new cases are being registered every year. FAO has estimated that every year Africa loses over 5 million cattle and other livestock in deaths caused by trypanosomiasis and uses over 35million doses of trypanocidal drugs in the futile effort to maintain livestock free of the diseases [2]. The potential area of tsetse infestation has been variously estimated at 66,000km 2 based on 1,6000meter above sea level breeding limit [3] 97,855km 2 based on a 1,600 meter above sea level breeding limit [4] and between 135000-220,000 km 2 based on the maximum dispersal up to 11,700-200,000 meter above Research Journal of Chemical and Environmental Sciences Res. J. Chem. Env. Sci., Volume 1 Issue 5 December 2013: 89-98 Online ISSN 2321-1040 CODEN: RJCEA2 [CAS, USA] Available Online http://www.aelsindia.com ©2013 AELS, India ORIGINAL ARTICLE