http://dacnet.nic.in/ppin/pack/ipmpackage/groundnut.pdf 

Integrated Weed Management in Groundnut

   Cultural Practices:

• Summer deep ploughing of fields for destroying the underground  vegetative parts of perennial weeds.
• Two mechanical weedings each at 15-20 days and 30 -45 days after sowing to   keep the crop weed free for 6 weeks.

Chemical Control:

• Apply Oxyflourofen  (0.15 - 0.25 kg a.i /ha. as pre-emergence) or
• Fluehloralin(1.0 kg a.i./ha as pre-plant incorporation) or
• Pendamethalin (0.75 -1.5 kg a.i /ha. as pre-emergence) or
• Imazethepyrin (0.1- 0.15 kg a.i /ha as early/post emergence) to weeds within 7-14 days after sowing for effective weeds control.