WASHINGTON — Many major emerging economies have weakened since the spring, the International Monetary Fund said on Tuesday in the latest update to its economic forecasts, while advanced economies, including the United States and Europe, continue to trudge along with subpar growth and the euro area remains mired in recession.

The fund now expects the global economy to grow about 3.1 percent in 2013, the same rate as in 2012 and down from growth of 3.9 percent in 2011. That is 0.2 percentage points lower than the Washington-based fund forecast in April.

Olivier Blanchard, the fund’s chief economist, said in the periodic update that emerging economies were experiencing a “slowdown in underlying growth,” and the fund lowered its forecasts for China, India, Brazil, Mexico, South Africa and Russia, among other countries. “It’s clear that these countries are not going to grow at the same rate as they did before the crisis,” he said.

Given that emerging economies have in no small part powered the global recovery, their slowdown has a significant effect on the rest of the world, the fund said. For instance, Mr. Blanchard said, if growth in the so-called BRICS — Brazil, Russia, India, China and South Africa — were 2 percentage points slower than expected, a half-percentage point would be knocked off the United States’ growth rate. “It matters,” he said.