Efficacy of flumioxazine 50% SC for weed control in soybean

Abstract

The experimental research was conducted to study efficacy of flumioxazine 50% SC at various dosage for weed control in soybean over Pendimethalin 30% EC, Oxyflourfen 23.5 % EC and Chlorimuron Ethyl 25% WP. Weed control efficiency, number of pods per plant, number of seeds per pod, 100 seed weight, grain yield, haulm yield, harvest index, net return and BC ratio were evaluated. The results revealed that pre-emergence application of flumioxazine at 250 g/ha recorded higher weed control efficiency at all stages of crop growth followed by pre-emergence application of flumioxazine at 150 g/ ha. Pre-emergence application of flumioxazine at 112.5 g/ ha recorded increased yield and economic returns in soybean. Preemergence application of flumioxazine at 112.5 g/ ha can reduce the weed growth below the economic threshold level and increase the yield and net return and hence it provides an option to farmers to manage weeds effectively along with improved growth leading to higher productivity of soybean.Key words: Flumioxazine, Pre emergence, Soybean, Weed control efficiency.Soybean [Glycine max (L.) Merrill] is a crop of multiple qualities as it is both a pulse and oilseed crop. Being a rainy-season crop, it is heavily infested with weeds. Seasonlong weed infestation in soybean results in loss up to 79 per cent (Reddy et.al.,1998). Cultural and mechanical methods of weed control are not always effective in first 45 days (Prabhakar et. al., 1992). This necessitates provision of suitable herbicides to the farmers that can be cost effective and cope up with the scarcity of labour at the time of need. Under such circumstances, use of effective herbicides in suitable dose remains the pertinent choice for controlling the weeds. Several new molecules are being tested for their weed control efficacy in soybean. Although, the research has provided a few options involving pre-plant incorporation (trifluralin and fluchloralin), pre-emergence (alachlor, pendimethalin, metolachlor and clomazone) and postemergence (imazethapyr, quizalofop ethyl and chlorimuron ethyl), there is a need to identify newer molecules for selective management of weeds and to overcome the problem of acquiring resistance by certain weeds against recommended herbicides.Flumioxazine (N-phenylphthalimide) is a new molecule which acts on weeds by inhibiting protoporphyrinogen oxidase, an enzyme important in the synthesis of chlorophyll. Keeping these points in view, the experiment was taken with flumioxazine 50% SC with the objective to evaluate the various doses of flumioxazine 50% SC for weed management in soybean.The experiment was conducted at Agricultural Research Station, Bhavanisagar, in the Western zone of Tamil Nadu. The experimental field is located at 11 0 29'N latitude and 77 0 08'E longitude with an altitude of 256 m above MSL. During the cropping period, the average minimum and maximum temperatures were 17.6 0 C and 34.2 0 C, respectively and the total rainfall received was 24.8 mm. The average relative humidity at 0722 and 1422 hrs were 83.9 ...