With Pennsylvania's budget deadline rapidly approaching, Gov. Rendell warned yesterday that proposed Republican budget cuts would reverse years of progress in autism treatment, and he urged parents of autistic children to pressure lawmakers to vote for an increase in the income tax to preserve the programs.

Rendell, a Democrat, said that his proposal for an income tax increase lasting three years had encountered stiff opposition and that the antitax sentiment had intimidated some lawmakers.

"We have the power to change things," Rendell said of his administration and the legislature. "Take a little risk. Do the right thing."

Republicans responded that cuts to autism services had been limited to public awareness and other information programs and would not affect treatment.

Senate Appropriations Committee Chairman Jake Corman of Centre County said there was "zero" chance that an increase in the income tax would pass the Republican-controlled Senate.

"I understand that the governor is well-intentioned," he said, "but this is not the time to ask the people of Pennsylvania for more money. People are hurting."

Rendell spoke at a rally at Bryn Mawr College in support of expanded autism services. Saying he needed six more votes in the Senate, he urged the more than 100 people in attendance to contact lawmakers and urge them to vote for the tax increase.

Otherwise, years of hard-won advances would be reversed, he said.

"All cuts are not the same," Rendell said. "We rejected these cuts because the programs are so important."

Of his proposed tax increase, he said: "We can do this if we can convince the Senate Republicans to do those things that we think are the right thing to do."

Rendell's remarks echoed his warnings last week as he traveled the state, where he said economic-development programs would be reduced if the legislature failed to raise taxes and the state's $3.5 billion budget gap was not closed.

Under the state constitution, the governor and legislature have until June 30 to adopt a new budget, but Corman and others say it is highly unlikely that they will make that deadline. For one thing, Corman predicted, Democrats would have a hard time finding votes for a tax increase in their own caucus.

Though it faces a deadline, the state will likely be able to function for at least a few weeks while Rendell and the legislature try to find common ground.

The rally at Bryn Mawr's Graduate School of Social Work and Social Research was attended by autistic children, their parents, and other relatives.

One theme emerged: Services for autistic children, though expanded in recent years, virtually disappear once the children turn 21. As the disorder is diagnosed in more and more people, the need for state programs to back up hard-pressed parents will only grow.

"For parents with autistic children, the single most important number is 21, when educational services end," said David Fine, a Harrisburg lawyer at the rally whose son, Kenneth, is autistic. "We know our efforts will not be enough."

Rendell contended that his proposal for a temporary income tax increase was a modest initiative. At 3.07 percent, the state's personal income tax is among the lowest in the nation, far below those in New York and New Jersey.

Rendell is proposing a 16.3 percent increase to 3.57 percent that would end after three years. Even the higher rate would be the third-lowest in the nation, he said.

He estimated that the tax increase would add $5 a week to the tax bill of a family with an annual income of $50,000, the average in Pennsylvania.

Contact staff writer Chris Mondics at 215-854-5957 or cmondics@phillynews.com.