Efficacy of one botanical and three synthetic insecticides against silverleaf whitefly, Bemisia tabaci (Hem.: Aleyrodidae) on cucumber plants in the field

The silverleaf whitefly, Bemisia tabaci (Hem.: Aleyrodidae), is a key pest of greenhouse crops. Nymphs and adults feed on plant sap and excrete honeydew, resulting in reduction of yield and quality. This pest has a high potential for developing resistant biotypes against different insecticides. Therefore, it is necessary to study the efficacy of different categories of insecticides against B. tabaci. In this research, efficacy of imidacloprid (0.5 l/ha), thiacloprid + deltamethrin (0.75 l/ha), pyrethrum (4 l/ha) and thiamethoxam + lambda-cyhalothrin (0.3 and 0.4 l/ha) with four replications were studied in a completely randomized block design in Yazd and Bushehr provinces of Iran. Mean (± SE) efficacy of imidacloprid, thiacloprid + deltamethrin, pyrethrum and thiamethoxam + lambda-cyhalothrin (0.3 and 0.4 l/ha) were 73.42 ± 3.41, 89.57 ± 2.86, 90.29 ± 2.79, 68.13 ± 3.37 and 75.62 ± 3.76% against B. tabaci nymphs 7 days after treatment in Yazd, respectively; while in Bushehr, they were 57.30 ± 3.37, 68.45 ± 4.65, 64.17 ± 2.87, 30.0 ± 4.56 and 53.0 ± 3.35%, respectively. Thiacloprid + deltamethrin, pyrethrum and thiamethoxam + lambda-cyhalothrin (at 0.4 l/ha) can be suitable candidates in IPM programs of B. tabaci.