Under attack over sharp rise in prices of essential food items, the Centre today asked states to crack down on black marketers. Food and Agriculture Minister Sharad Pawar told the Lok Sabha that Centre may extend a ban on futures trading on sugar beyond December. Besides sugar, there is a a ban on futures trading on rice, tur and urad.Replying to a debate on the price rise of essential commodities, Mr Pawar said, State governments have to ensure that hoarding and black marketing will not be there. He said, States have reported that they have detained hardly 156 persons to check prices from January to October.Observing that prices of wheat and rice are reasonably stable, the Agriculture Minister said situation is serious in case of pulses, sugar, onion and potato. He said price rise in potato and onion is temporary and situation will improve after the arrival of rabi crop.Intervening in the debate, Finance Minister Pranab Mukherjee blamed some states for shortage of some commodities, saying mismanagement by states is leading to short supply. His remarks assume importance as food inflation crossed 15 per cent, fuelled by more than doubling of potato prices in a year.