questions: asking about timing of herbicide apply in rice and timing of  pyrazosulfuron ethyl  and butachlor in rice 
 answers: told him there are three different herbicide based on time of application namely preplanting(applied before transplanting), pre emergence(before emergence of weed) and post emergence (after emergence of weed) herbicide.herbicide is very effective if we can use line transplanting method.it should not  applied during the water log condition.told him about pyrazosulfuron ethyl (trade name-sathi) and butachlor both are  pre emergence  herbicide which can applied 3dat in rice.