TORONTO — Canada’s dollar plunged more than a cent and a half today after traders turned to the U.S. dollar in a so-called flight to quality as fear intensified that the Greek debt crisis will spread. The loonie dropped to 1.59 cents to close at 98.27 cents US on currency markets, just off its intraday low of 98.21 cents. The Canadian currency’s drop and sliding stocks in Europe and North America reflect the worsening of Europe’s government debt crisis. Greece’s credit rating was downgraded to junk status and Portugal’s debt was lowered on fears the trouble could spread.