Art Cashin says "alarm bells" will go off for stocks if the yield on the 10-year Treasury note hits 2.9 percent.
Cashin, UBS' director of floor operations at the NYSE, also told CNBC's Bob Pisani at midday that rising interest rates are already causing some problems for stocks in emerging markets like Thailand, India and Indonesia.
"India is beginning to look particularly strange, and that's rather a large economy to be worried about," Cashin said. "Indonesia is getting pounded. You don't usually have these at the top of your list, but they lurk in the background."