Evaluation of Insecticides for Their Frequency and Rates Against Onion Thrips in ambo, Ethiopia

The tested insecticides caused mortality of onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) at various degrees of significance over untreated control. The results revealed that the Spindid plus, Spinal 160 S.C, and Pyractin 180 S.C at a lower rate ha^-1 gave a promising mortality percentage and was significantly (P≤0.05) different from the untreated control. The obtained yield showed on par at the minimum rate gave the highest onion bulb yield (13.33t/ ha) was obtained with Spindid Plus at a rate of 200 ml ha^-1, followed by Spinal 160 S.C at a rate of 250 ml ha^-1 (12.95 t/ ha), Pyractin 180 S.C at the rate of 250 ml/ ha (12.57t/ ha), and Prostar 72% E.C at the rate of 700ml/ha as a standard check. However, the minimum onion bulb yield obtained in untreated control (10.87t/ ha). Based on this finding repeated spraying of a low dose of a chemical was more effective.