Vol. 16 No. 2
Evaluation of pre and post emergence herbicides for weed control in rice bean (Vigna umbellata) crop under rain-fed condition
Author(s): S. R. ANAND, N. MURTHYAND B. S. LINGAPPA
Abstract: The experiment was conducted for three years during Kharif season 2015-2017 using pre- and post-emergent weedicides along with manual weed control methods at Main Agricultural Research Station, Hebbal, Bangalore, Karnataka. The pooled data of three years indicated that, weed free check and hand weeding twice at 3rd and 5th Weeks After Sowing (WAS) were found superior by recording significantly lower weed count, weed dry weight and weed control efficiency. Among the herbicides, application of pendimethalin 38.7% CS 1.0 kg a.i. ha-1 as Pre-emergence + one hand weeding at 5th WAS recorded lower weed count, weed dry weight and weed control efficiency followed by application of oxyfluorfen 23.5 EC 50 g a.i. ha-1 as Pre-emergence + one hand weeding at 5 WAS. However, plant height, numbers of branches plant-1, number of pods plant-1 were significantly higher with weed free check which was on par with integrated weed management of application of pendimethalin 38.7% CS 1.0 kg a.i. ha- 1 as Pre-emergence + hand weeding at 5th WAS and hand weeding twice at 3rd and 5th WAS. With respect to economics, higher net returns and B:C ratio were found in application of pendimethalin 38.7% CS 1.0 kg a.i. ha-1as pre-emergence + hand weeding at 5th WAS followed by application of oxyfluorfen 23.5 EC 50 g a.i./ha as Pre-emergence + hand weeding at 5 WAS (2.61). None of the herbicides alone treatments were found effective in controlling all the types of weeds. Whereas, pre-emergence application followed by one hand weeding at 3rd week after sowing proved better for controlling weeds. The post emergent herbicides viz., fenoxaprop-p-ethyl (9% EC) 50g a.i. ha-1post- emergence (3 WAS) and quizalofop-p-ethyl (5% EC) 50g a.i. ha-1 post- emergence (3WAS) did not give significant result when compared to pre emergence weedicides alone.
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