For the second time in recent weeks, Arlington County Board member Barbara Favola is under fire in one of the state’s nastiest primary races this year.

This time, five Democratic members of the House of Delegates, including two who have not endorsed in the race, have condemned her for what some of them say were racist comments about her opponent Jaime Areizaga-Soto.

Lowell Feld, a liberal blogger who supports Areizaga-Soto and lives in the Northern Virginia district, said he received a call from Favola last week in which she allegedly said Areizaga-Soto would have no base in the district because his family hails from Puerto Rico.

Dels. Mark Keam and Patrick Hope, who have not endorsed in the race, joined Dels. David Englin, Scott Surovell and Kaye Kory, who support Areizaga-Soto, in criticizing Favola. (Englin’s wife also works for Areizaga-Soto).

“I can’t think of any justifiable reason why anyone — particularly a Democratic officeholder — would say such things about an ethnic minority candidate,’’ Keam said. “How can anyone in the year 2011 assume that an ethnic candidate cannot be elected without the support of fellow minorities?’’

Four delegates who are minorities, including Keam, represent majority white districts in Virginia.

Favola acknowledges the call, but strongly denies she said Areizaga-Soto could not be elected because of his ethnicity. Her supporters say she was answering a question from Feld about the make-up of the 31st district, which includes parts of Arlington, Fairfax and Loudoun counties, and merely commented on the low number of minorities in the district.

“These allegations are flat out untrue,’’ Favola said. “Jaime Areizaga-Soto and his supporters have hurled outrageous allegations at me throughout the campaign, but this takes the cake. Mr. Areizaga-Soto and his supporters have sunk to a new low in Northern Virginia Democratic politics.”

Favola’s campaign notes that she has played a significant role in creating a diverse community by supporting resolutions that acknowledge the value and contributions of Arlington’s minority populations and worked to ensure that critical county information is offered in Spanish.

Favola and Areizaga-Soto are running for the Democratic nomination to replace retiring Sen. Mary Margaret Whipple (D-Arlington). Whipple defended from Favola, who she endorsed, saying she was surprised that elected officials would make statements without all the information.

“The only basis is an oral account of a telephone conversation,’’ she said.

Republicans are in a fierce battle for control of the Senate, where Democrats hold a fragile 22 to 18 majority.

The 31st district— which is Democratic leaning — is playing host to one of the nastiest intraparty contests in the state. Areizaga-Soto, an attorney, and Favola have been trading barbs and accusations for weeks.

Last month, Favola asked her pollster to stop calling Areizaga-Soto a “Republican”after details about the poll became public.

“My campaign is about fighting for our entire community,’’ Areizaga-Soto said Monday. “I’ve lived the American dream and I’m disappointed that my opponent thinks so little of the voters of the 31st that she’d think mentioning my ethnic background would win her votes.”