* FTSEurofirst 300 loses 0.6 pct in volatile session
* Index down 6.3 pct since mid-September
* Ebola fears hurt shares in airlines, travel groups
By Blaise Robinson
PARIS, Oct 8 (Reuters) - European stocks sank on Wednesday, extending their week-long selloff and with a benchmark index hitting its lowest level since mid-August as mounting concern about global economic growth spooked investors.
At 1415 GMT, the FTSEurofirst 300 index of top European shares was down 0.6 percent at 1,321.23 points. The index has lost 6.3 percent over the past three weeks.
Europe's renewed sell-off mirrored overnight losses in Asian and U.S. equities after the IMF cut global growth forecasts.
In the latest evidence of economic malaise, China's services sector growth weakened in September as new business cooled, another sign of a slowdown in the world's second-largest economy. The figures came a day after German industrial output missed forecasts.
"It's concerns over global growth that are weighing on the equity markets," said James Butterfill, global equity strategist at Coutts. "If you look at Europe, there's very weak macroeconomic data. There's weak data coming out of China as well, so it does suggest weaker growth, and markets are perhaps adjusting to that."
Around Europe, UK's FTSE 100 index was down 0.2 percent, Germany's DAX index down 0.7 percent, and France's CAC 40 down 0.7 percent.
Shares in German business software maker SAP featured among the top losers, down 3.8 percent, as traders cited speculation of weak orders in the fourth quarter and after the company's finance chief urged staff to cuts costs in an internal memo.
Jitters over the spread of Ebola also hurt sentiment, with shares in airlines and travel companies losing ground. TUI lost 2.8 percent, Thomas Cook dropped 1.5 percent and IAG fell 1.1 percent.
Air France-KLM, which on Wednesday said the total cost of last month's two-week pilots strike was 500 million euros ($632 million), shed 2.6 percent.
Despite the sharp retreat, Allianz Global Investors' Joerg De Vries Hippen said he saw good value in European stocks.
"European stocks are the cheapest you can find, and the only investment where you can realistically expect returns of 5 percent per year given the good dividend yields," said De Vries Hippen, co-chief investment officer of European equities at Allianz GI, which manages 373 billion euros ($472 billion).
"Relative to bonds and other asset classes, equity is the only place to be."
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up
Editing by Alison Williams