Scots were urged to prevent the Eurosceptics, who have faced accusations of racism and sexism in recent days, from gaining their first parliamentarian north of the border.
The moves came a day after The Herald revealed that seven in 10 Scots back stricter immigration controls, a key part of Ukip's policy pitch.
Amid growing fears the party could top the poll in England, George Osborne last night threw a bone towards wavering voters with a stinging attack on Europe. An unreformed European Union is a "risk to our long-term prosperity," the Chancellor said in a speech to business leaders, a message that will also be interpreted as an attack on his Coalition partners the Liberal Democrats.
On a day when political leaders from all parties were out and about on the campaign trail there was also further embarrassment for the Labour leader, Ed Miliband, and for Prime Minister David Cameron.
Today Scots will elect six members of the European Parliament. Last time around the SNP and Labour took two seats each, with the Conservatives and the Lib Dems each taking one.
Following polls which suggest voters will continue to punish the Lib Dems for entering into Coalition with the Tories, the SNP said that the fight for the sixth and final Scottish seat was between its candidate and Ukip.
First Minister and SNP leader Alex Salmond urged voters to reject what he described as the "appalling politics of intolerance" being peddled by Ukip.
"People of all political shades who want to stop Ukip can play their part and back... the SNP," he added.
Labour and the Liberal Democrats attacked Ukip and the SNP, accusing both of offering a "false choice" over Europe.
On the campaign trail in Paisley, Renfrewshire, Labour's shadow chancellor, Ed Balls, said he thought Ukip was "looking a bit flakey" following days of negative headlines.
Mr Balls said: "Here in Scotland they don't have any MEPs and hopefully we can keep it that way."
But he added: "If you're voting for the SNP then you're voting for confusion over Europe."
Campaigning in the Highlands Liberal Democrat Chief Secretary to the Treasury Danny Alexander said that although they are "very different parties" Ukip and the SNP's "plans to pull us out of the UK and wrench us out of the EU would have exactly the same damaging effect on Scotland and our economy".
He also appeared to echo an earlier warning by Mr Osborne that Ukip's call to take the UK out of the EU would hurt the economy.
For his part Mr Farage, savaged last week for an interview defending comments that he did not want to live next door to Romanian men, admitted that his 80-year-old aunt pretended they were not related as "it's safer".
The Ukip leader also insisted he did not want to lead the "out" campaign if there is a referendum on the UK's EU membership in 2017. That role "needs a figurehead and I'm a warrior, not a figurehead", he said.
After a disastrous day earlier in the week, when he was criticised for not knowing the name of a local labour leader, Mr Miliband faced further embarrassment when unflattering photographs emerged of him eating a bacon buttie.