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Effectiveness of imidacloprid in combination with a root nitrogen fertilizer applied to tomato seedlings against Bemisia tabaci (Hemiptera: Aleyrodidae)

Sun, Yuan-Xing, Liu, Tong-Xian
Crop protection 2016 v.80 pp. 56-64
Bemisia tabaci, Hemiptera, active ingredients, adults, boron, calcium, cost effectiveness, egg production, field crops, greenhouses, growing media, imidacloprid, leaves, magnesium, mortality, nitrogen fertilizers, nymphs, pests, seedlings, subsurface irrigation, tomatoes
The whitefly Bemisia tabaci (biotype B) is a worldwide pest of vegetables and field crops. We tested the efficacy of imidacloprid (IM) with a root fertilizer ‘Root Feed (RF)’ (9% N, 7% Ca, 1.5% Mg and 0.1% B) sub-irrigated in the growing medium against the whitefly on tomato. Tomato seedlings (3–4 true leaves) were treated with 0, 3, 6 or 12 mg active ingredient (a.i.) seedling−1 of IM and with RF (0, 0.02, 0.04 or 0.08 ml seedling−1). The efficacy of 12 mg IM seedling−1 was further evaluated in the greenhouse for 60 days. The survival of B. tabaci adults, nymphs, and egg production were negatively affected by the treatments in a dosage-dependent manner. Treatment of 12 mg IM seedling−1 caused >60% adult and nymph mortality 50 days after treatment (DAT). The active ingredient of IM in tomato leaves also increased with the increase of IM dosage. The RF exhibited a limited effect on B. tabaci. However, the mortality of whitefly adults and nymphs treated with RF (0.02 or 0.04 ml seedling−1) positively interacted with IM, and was greater than IM alone. In the greenhouse, 12 mg IM seedling−1 greatly reduced the number of whitefly adults and increased the dry weight of the tomato plants at 30 DAT. In conclusion, application of 12 mg IM seedling−1 on tomato seedlings before transplanting effectively controled B. tabaci for up to 50 days, and the efficacy of IM combined with 0.02 ml RF seedling−1 performed even better. This could be a cost-effective method for managing B. tabaci on tomato and other vegetables.