Field studies were conducted to assess and compare the efficacy of three neonicotinoid insecticides (imidacloprid Goucho 70% WS, Pestador 25% and dinotefuran Mti-446, 20% WP) against Bemisia tabaci (Gennadius) applied as potato seed tubers dresser. All experiments were conducted at the Agriculture Research Station, Etay El Baroud, El-Beheira Governorate, Egypt, during the growing seasons of potato in 2004& 2005. The commercial cultivar of the crop used in this study was the potato variety Necole. The imidacloprid Goucho was significantly better than the imidacloprid Pestador and dinotefuran Mti-446 in controlling B. tabaci and deterring oviposition activity. Gaucho significantly reduced B tabaci adult populations by 82.90% in 2004 and 84.71% in 2005. Pestador induced 69.34 and 74.21% reduction against B. tabaci adult in 2004& 2005, respectively. Comparable reductions in adult white fly populations were observed in potato plots treated with dinotefuran (65.63 and 70.62% reduction in 2004& 2005), respectively. Gaucho was significantly better against immature than Pestador and dinotefuran in both of growing seasons (2004& 2005). Gaucho resulted in 89.45 and 89.70 mean percentage reductions in immature numbers while, Pestador induced 78.75 and 76.82 mean % reduction in 2004& 2005, respectively. Dinotefuran gave 75.47 and 73.73 mean percentage reductions respectively in immature numbers in 2004& 2005. Neonicotinoid potato seed tubers dresser protected potato against B. tabaci attack for up to 65 day after sowing. The present study provides motivation to implement imidacloprid potato seed tubers dresser application strategy as a part of white fly management program. Not only potato seed tubers application of the neonicotinoids is effective in controlling whitefly population, but also the impact of potato seed tubers dresser application on natural enemies would be expected to be less than that of foliar application because most natural enemies would not be exposed directly to the insecticide.
Key words: neonicotinoid, imidacloprid, dinotefuran, Bemesia tabaci.
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