Abstract

                                Purple nutsedge is a perennial, one of the world worst weed, ravages the field continuously throughout the year in the tropical regions. It thrives and dominates under any environmental conditions. Normally weeds compete with the crops for the nutrients, water, space, light and other essential requirements. Inadequate control of weed at appropriate stage is considered as a major constraint for high yield.There is more number of pre-emergence, early post-emergence and post-emergence herbicides coming up in the market with wide spectrum of weed control efficiency. The availability of effective and new herbicides and herbicide combinations in the recent times have led to control of established weeds before crops, so as to reduce their competition with crops and increase the crop yields. With this background, field experiments were carried out to evaluate the effect of different herbicides for control of Cyperus rotundus in a non-crop ecosystem in the farmer’s field, Chinnankuppam at Dharmapuri district, Tamil Nadu during 2017 to 2018. Cyperus rotundus wasfound to bethe predominant weed in the experimental field compared to broad leaved weeds such as Parthenium hysterophorous and grasses like Chloris barbata and Cynodon dactylon. Pre-emergence, early post-emergence and post-emergence herbicides viz., metribuzin, halosulfuron methyl, glyphosate and 2,4-D were applied individually as well as different combination were used for the management of purple nutsedge (Cyperus rotundus). Among the herbicides, early post-emergence application of halosulfuron methyl at 50 g ha^-1fb post-emergence application of glyphosate at 1.00 kg ha^-1resulted in lower Cyperus density, dry weight and higher control efficiency followed by early post-emergence application of halosulfuron methyl at 75 g ha^-1.

Key words : Purple nutsedge, Herbicides, Weed characters