The aim of the present research work was to investigate the effect of orange and cinnamon oil on the occurrence and harmfulness of Thrips tabaci Lind on onion. In 2014, the nonchemical treatment was made with Prev-B2 (the concentration of 0.4%), which contains: 4.2% of orange oil, 2.1% of boron and product Canol 70% p/p exstract of Cinnamomum zeylanicum. In 2015, only Prev-B2 product was used. The standard sprayer was used and the treatments were done: twice in 2014 and three times in 2015. The thrips were collected directly from the leaves, using standard sweeping nets. The plants were examined to find the leave damages caused by feeding thrips. In 2014, Thrips tabaci was recorded from 11 June to 19 August, whereas in 2015 from 24 June to 4 August. Over two years of observations, the highest number of thrips was collected from onion growing on control plots (not treated with any preparation). Also, the mean percentage of areas damaged on the onion leaves was significantly higher on control plots than on plots treated with cinnamon oil in 2014 and orange oil in 2015.
