Bio-Efficacy and Phytotoxicity Evaluation of Quizalofop-Ethyl (5% EC) for Management of Weeds in Onion

A field experiment was conducted at Agricultural Research Station, Bhavanisagar of Tamil Nadu Agricultural University, during rabi 2012–13. Twelve treatments viz., early post-emergence application of new formulation of quizalofop-ethyl at 37.5 (T₁), 50 (T₂), 75 (T₃) and 100 (T₄) g a.i ha⁻¹, already registered early post-emergence herbicide quizalofop-ethyl (Targa super) at 37.5 (T₅) and 50 (T₆) g a.i ha⁻¹, pendimethalin at 1.0 kg a.i ha⁻¹ + Hand Weeding on 45 DAT (T₇), pendimethalin at 1.0 kg a.i ha⁻¹ + Mechanical Weeding on 45 DAT (T₈), oxyfluorfen at 0.2 kg a.i ha⁻¹ + Hand Weeding on 45 DAT (T₉), oxyfluorfen at 0.2 kga.i ha⁻¹+ Mechanical Weeding on 45 DAT (T₁₀), Hand Weeding on 25 and 45 DAT (T₁₁) and unweeded check (T₁₂) were laid out in randomized block design with three replications. Grasses was predominantly found in the experimental field. Lower density of grasses was recorded under early post emergence application of quizalofop-ethyl at 100 and 75 g a.i ha⁻¹ due to control of emerged as well as emerging grass weeds. Control of weeds during the critical period of crop weed competition by early post-emergence application of new molecule of quizalofop-ethyl at 75 g a.i ha⁻¹ led to better plant growth, effective utilization of nutrients and higher dry matter production which resulted in increase in yield and was comparable with pre-emergence application of oxyfluorfen at 0.2 a.i kg ha⁻¹ + hand weeding on 45 DAT and oxyfluorfen at 0.2 kg a.i ha⁻¹ + mechanical weeding on 45 DAT.