Efficacy of new formulations of triasulfuron on weeds in wheat (Triticum aestivum) and their residual effects on succeeding maize (Zea mays)

Abstract

A field experiment was carried out at research farm, Institute of Pesticide Formulation Technology, Gurgaon over 2 years (2011 and 2012) to evaluate the bioefficacy of triasulfuron 20 WG (New source) in wheat [Triticum aestivum (L.) emend. Fiori & Paol.] and its residual effect on succeeding maize (Zea mays L.) crop. Different doses of triasulfuron 20 WG (New source) @ 75 and 100 g/ha; triasulfuron 20 WG (existing source) @ 75 and 100 g/ha; metsulfuron 20 WG @ 20 g/ha were applied at 35 days after sowing of crop with knapsack sprayer using flat fan nozzle @ 450 litres water/ha and 3 hand weedings at 15 days interval after emergence of the crop in weed free check. The effect of above mentioned treatments on weed density, weed biomass and weed control index (WCI %) were recorded at 60 days after application (DAA) against broad leaved weeds in wheat fields. The results indicated that the main broad-leaved weeds in wheat field were Chenopodium album L., Anagallis arvensis L., Melilotus sp., Rumex sp. and Lathyrus aphaca L. Metsulfuron 20 WP @ 20 g/ha and existing source of triasulfuran 20 WG @ 75 g/ha was least effective against broad leaf weeds. New source of triasulfuran 20 WG @ 100 g/ha was most effective in respect of weed control and dry-matter accumulation by weeds. Grain yield of wheat with the use of triasulfuron 20 WG (New source) @ 100 g/ha was 3.96 and 3.95 t/ha during first and second year of experimentation, which was the highest among the herbicide formulation. No carry over effect of these her- bicides was observed on succeeding maize.