Life history parameters of Thrips tabaci (Thysanoptera: Thripidae) on six commercial cultivars of canola

The onion thrips, Thrips tabaci Lind. (Thysanoptera: Thripidae), is an important pest of the canola crop, Brassica napus L., in the Ardabil region. In this study, life history parameters of T. tabaci were investigated on six canola cultivars, namely: Talayh, Zarfam, RGS003, Opera, Option500, and Hayola401. Experiments were performed in a climate chamber set at 25 ± 1°C and 55 ± 5% RH under 16L:8D. The results indicated that the development time of immature stages was significantly longer on RGS003 than on Opera, Hyola401, Zarfam, Option500, and Talayh. The onion thrips reared on RGS003 had the lowest number of eggs laid per female (15.5) and the lowest survival rate (40%) among the tested cultivars. The lowest intrinsic rate of natural increase (rm) and population growth rate (λ) were observed on RGS003, and were the highest on Zarfam. The generation time (T) was shortest on Zarfam (21.5 days) and longest on RGS003 (26.5 days). Similarly, the doubling time (DT) was shortest on Zarfam (4.5 days) and longest on RGS003 (8.1 days). Considering the significant effect of the host plant on the life history parameters of onion thrips, it was concluded that RGS003 is the least suitable cultivar among the other tested canola cultivars for integrated management of onion thrips in canola fields.