Updated

U.S. House candidate Larry Diedrich (search) told those gathered in New York City for the GOP National Convention that his opponent is not getting the job done in Congress.

Diedrich, who is challenging Democrat Stephanie Herseth (search) in the Nov. 2 general election, was among several Republican House candidates allowed to make brief speeches Monday at the convention. Diedrich's address to the group lasted 55 seconds.

"It's a good thing we've got my friend Gov. Mike Rounds (search) working for us because so far our only representative is proving ineffective," Diedrich said.

"South Dakota can't afford to waste its only House seat," he added. "We need a congressman who knows how to get things done."

Announcing last week that he was invited to speak at the GOP gathering, Diedrich said his appearance was an indication of the national prominence given South Dakota's U.S. House race.

It's important that state voters elect him for his conservative views, and for his experience as farmer-businessman, parent and taxpayer, he said.

Tessa Gould, Herseth's campaign manager, said Diedrich should not have used the GOP convention to criticize his opponent.

"South Dakotans are clearly tired of negative campaigns, and it's unfortunate that Larry used his time on stage to attack Representative Herseth," Gould told The Associated Press.

Herseth has tried to convince voters that she hit the ground running in Washington after being sworn in June 3 as the state's first female in the U.S. House.

Gould said Diedrich has been lying to the media about Herseth's record in Congress. Gould said she is worried because Diedrich has become increasing combative since losing the special election.

"This new pattern of attacks, based on blatantly untruthful and demonstrably false statements, takes things to a new and ugly level and dramatically changes the tone of this campaign," Gould said.

Jessica Towhey, Diedrich's press secretary, said he is merely informing voters about Herseth's congressional record.

"For the first time, Stephanie Herseth has a voting record," Towhey said Monday. "These are not personal attacks. This is taking a look at her record and letting people know what is going on in Washington, D.C."

Diedrich also told the convention on Monday that South Dakota is poised to become a leader in ethanol, biodiesel and wind energy. Agriculture continues to be the top industry in South Dakota, but the state must broaden its economic base, he said.

"We realize that our future also lies in technology and diversifying our economy," Diedrich said.

Diedrich, who planned to return to South Dakota on Tuesday said House candidates were told to limit their convention speeches to 100 words. It is necessary to restrict speeches in order to keep the convention on schedule, he said.

"They have to limit things. Anybody, let alone a politician, if you give them any freedom they'll use every bit of it plus a little more," he quipped.

Diedrich said he also got to shake Vice President Dick Cheney's hand and speak with him briefly at the convention.

"It's been an interesting day to say the least for a kid who has never been to a national GOP convention before," Diedrich said.

Herseth defeated Diedrich by 3,005 votes in a June 1 special election to fill the vacancy created on Jan. 20 when Republican Bill Janklow's resignation from Congress took effect. Janklow, a former state attorney general and four-term governor, abandoned his federal post after being convicted of second-degree manslaughter for the traffic death of a Minnesota man last August.

John Thune, who is challenging U.S. Sen. Tom Daschle, D-S.D., in November, also spoke Monday to GOP delegates.

Twenty-seven South Dakotans, including Rounds, Lt. Gov. Dennis Daugaard and state GOP Chairman Randy Frederick, are attending the GOP gathering as delegates.