Dear Ahssan

you can use Metribuzin (Sencor) @ 0.75-3 kg/ha. or diuron @ 0.5-2.5 kg/ha.

The link provided by Ashok Kumar Meena could not be opened. Have no idea about post emergenec application of metribuzin in cotton, but the dose (750 to 3000 g a.i./ha) may be checked.

The following herbicides are approved by Govt of India for application as post-emergence in cotton:

Fenoxaprop-p-ethyl 67.5 g a.i./ha with a spray volume of 375-500 litre water and waiting period of 87 days from last application.

Glufosinate Ammonium 13.5% SL (15% w/v) 375-500 g a.i./ha with a spray volume of 500 litre water and waiting period of 96 days from last application.

Paraquat dichloride 24% SL 300-500 g a.i./ha (2-3 leaf stage of weeds, inter row application) with a spray volume of 500 litre water and waiting period of 150-180 days from last application.

Pyrithiobac Sodium 10% EC 62.5-75 g a.i./ha with a spray volume of 500-600 litre water and waiting period of 95 days from last application.

Quizalofop-ethyl 5% EC 50.5 g a.i./ha with a spray volume of 500-600 litre water and waiting period of 95 days from last application.

The following link may be seen:

http://agritech.tnau.ac.in/crop_protection/pdf/7_%20Major_use_herbicides.pdf

Quizalofop P Ethyl will be used to control narrow weeds.

@Saddam Hussain sb.

Thanks for your reply but read the question again. I am asking for post emergence weedicide which can be directly sprayed on cotton crop.

check this link maybe help you

Article Halosulfuron Methyl: A New Post Emergence Herbicide in India...

Directed spray of halosulfuron methyl 75 WG @67.g a.i./ha (Sempra 90g/ha) at proper moisture using flat fan nozzle can be applied at 3-5 leaf stage of Cyperus or before flowering in Cyperus. This herbicide is effective on Cyperus underground nuts also.No phyto toxicity was observed in cotton crop. You can use glyphosate as directed spray at 3-5 leaf stage of Cyperus.

Halosulfuron gives more than 95% control of Cyperus. This product is marketed in India by Dhanuka Agritech Ltd.