Effectiveness of Some Insecticides Against Thrips (Thrips tabaci) on Three Onion (Allium cepa L.) Varieties

Thrips (Thrips tabaci L.) (Thysanoptera: Thripidae) is one of the important insect pests which attack the onion crop. Experiments were carried out to evaluate the effectiveness of different insecticides on thrips management by using three onion varieties “Red” (Red Grano), “Yellow” (Yellow Creole), and “White” (White Grano). Four insecticides were used at the full and half recommended concentration. Experiments were carried out using randomized complete block design with six treatments (three varieties, two doses (3 and 1.5 ml/L), and three replications for each insecticide. The results obtained showed that the number of thrips was statistically significant between treatments. The dose 3 ml/L was more effective than the 1.5 ml/L for all varieties, 14 days after treatment. The efficacy rate of Vertimec® insecticide reached 27.37, 27.34 and 26.73% at the dose 3 ml/L for the three varieties, respectively. The efficacy of Actara® insecticide reached 53% with the yellow onion variety at the concentration of 3 ml/L. The Pinto® insecticide was more efficient on the red onion variety at the same concentration. The highest efficacy of Decis® insecticide was obtained on yellow onion variety 44.3%, using the same concentration of 3 ml/L. Keywords: Allium cepa L., onion, thrips, Thrips tabaci, insecticides.