US STOCKS-S&P 500 hits lowest since March as rate fears deepen
* Wal-Mart surges after results beat estimates
* NY Fed's Dudley says June, July hike "reasonable"
* Monsanto rallies after Bayer makes unsolicited bid
* Indexes end down: Dow 0.52 pct, S&P 0.37 pct, Nasdaq 0.56 pct (Updates to close)
By Noel Randewich
May 19 (Reuters) - The S&P 500 fell on Thursday to its lowest since March as Wall Street became more worried that the Federal Reserve might raise U.S. interest rates as early as June.
The timing of future Fed rate hikes in the face of a sluggish economy is a major ongoing concern among stock investors who have benefited from historically low borrowing costs since the 2008 financial crisis.
In a new blow to Wall Street's confidence, New York Fed President William Dudley said the U.S. economy could be strong enough to warrant a rate increase in June.
That followed the release on Wednesday of minutes from the Fed's April meeting that showed most policymakers thought a June rate hike was appropriate, surprising many investors who had expected policymakers to wait until September due to a lackluster economic recovery. Continuación...