Evaluating the Efficacy of Insecticide on the Management of Onion Thrips (Thrips tabaci, Lindemann) in Northwestern Zone of Tigray

Ethiopia has enormous potential to produce the onions throughout the year both for domestic use and export market. It is also the most cultivated and high market value of vegetable crops in Tigray Northern Ethiopia. However, the productivity of onion is highly constrained such as insect pests, diseases, lack of improved verities, lack of improved management practices etc. The major insect pest of onion is Onion thrips and important pests especially in areas where onions are grown under irrigation. The purpose of this study was to test the insecticide chemicals application and application frequency on the Onion production technologies. Therefore, field experiment was conducted to evaluate the insecticide chemical applications with frequency application in 2017 and 2018 under irrigation conditions. Thirteen treatments were used three different insecticide types namely Karatae 5% EC, Dimethote 40%EC, Profit72%EC with four different spraying frequency and untreated (control) laid out in Randomized Complete Block Design (RCBD) with three replications. The current findings showed that the profitable yield was obtained Karatae 5% EC (1st spray) (14.25 t ha-1) followed by Profit72%EC (4th spray) that is (20.25 t ha-1) and the obtained profit was 128053 &181788 birr per ha with the maximum Marginal Rate of Return of 3025 & 2417% respectively in Tselemti woreda. In Medebaayzana woreda also, the profitable yield was obtained Karatae 5% EC (1st spray) (25.79 t ha-1) followed by Karatae 5% EC (4st spray) at (27.75 t ha-1) & Dimethote 40% EC (3rd spray) at (25.78 t ha-1) and 231976, 249463 & 231544 birr per ha obtained profit with the maximum Marginal Rate of Return of 2634, 2395 & 2311 % respectively. Therefore, Karatae 5% EC (1st spray) in Tselemti & Medebayzana woreda & Profit72%EC (4th spray) in Tselemti woreda and Dimethote 40% EC (3rd spray) in Medebayzana woreda was profitable preventive Onion Thrips for Onion production in the studies area.