* WTI crude falls below $58 a barrel
* China data hits materials sector
* Adobe up after results, to buy Fotolia
* Indexes off: Dow 1.2 percent, S&P 0.9 percent, Nasdaq 0.5 percent (Updates to early afternoon)
By Chuck Mikolajczak and Sinead Carew
NEW YORK, Dec 12 (Reuters) - U.S. stocks fell on Friday, putting the benchmark S&P 500 on track for its first weekly decline since mid-October after a further drop in oil prices and disappointing data out of China pushed investors away from the raw materials sector.
Oil's fall has added to worries about global demand and raised concerns about earnings for some energy companies, with year-end tax selling putting more pressure on the sector. Even bargain-hunters, for now, are staying away from energy shares.
"Don't try to catch a falling knife. That's what you have here," said Terry Morris, senior equity manager for National Penn Investors Trust Company in Reading, Pennsylvania.
The S&P energy sector was down 1.3 percent. It is down almost 16 percent this year, the worst performing of 10 S&P sectors. The S&P 500 index was down 2.8 percent for the week.
Disappointing data that suggested China's economy softened in November pushed the materials sector down 2.3 percent, making it the worst-performing S&P sector on the day.
The drop in oil and weakness in China overshadowed strong U.S. consumer sentiment, which hit an eight-year high.
Some investors hope declining gas prices will boost consumer spending enough to offset the energy sector's woes. The consumer discretionary sector was one of few the 10 S&P sectors that turned positive and was last up 0.2 percent.
"It's not much but I'll take it," said Kim Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.
Arthur Hogan, chief market strategist at Wunderlich Securities in New York says energy is a distraction.
"The good news is that this is a tailwind for the consumer. That's a positive that's being ignored," said Hogan, who was also relieved that the U.S. Senate was able to approve a spending bill that ended the threat of a government shutdown.
Brent crude slipped to $61.35 a barrel, its lowest since July 2009, while WTI crude was last down almost 4 percent at $57.66 as worries persisted over a global supply glut and sluggish demand.
At 2:44 p.m. the Dow Jones industrial average was down 215.38 points, or 1.22 percent, at 17,380.96, the S&P 500 had lost 18.33 points, or 0.9 percent, to 2,017 and the Nasdaq Composite had dropped 22.43 points, or 0.48 percent, to 4,685.73.
Adobe Systems rose 10.8 percent to $77.27, making it the biggest gainer on the S&P 500 after it announced plans to buy stock photography company Fotolia, along with a stronger quarterly report.
Declining issues outnumbered advancing ones on the NYSE by 2,272 to 808, for a 2.81-to-1 ratio on the downside; on the Nasdaq, 1,688 issues fell and 1,025 advanced for a 1.65-to-1 ratio favoring decliners.
The benchmark S&P 500 index was posting 14 new 52-week highs and 34 new lows; the Nasdaq Composite was recording 47 new highs and 143 new lows. (Editing by Bernadette Baum, Meredith Mazzilli and James Dalgleish)