Whole Foods Market, the largest US organic and natural supermarket, is slowing its rate of new store openings and suspending its quarterly dividend, as its sales growth falters amid economic worries.

The retailer’s shares fell over 14 per cent in after hours trade to $19.60 as it drastically lowered its outlook for its 2009 fiscal year, which begins in October, and reported third-quarter earnings that dropped about 30 per cent.