By Silvia Aloisi
ROME (Reuters) - Italians vote for a second and final day Monday in local elections that are a test of whether a sex scandal, three corruption trials and a faltering economy have weakened Prime Minister Silvio Berlusconi.
Nearly a quarter of Italians are casting their ballot in 1,310 towns and 11 provinces. The most significant races are in the four big cities of Turin, Naples, Bologna and Milan -- Italy's business capital and Berlusconi's home town, where his centre-right coalition is at risk of losing for the first time in nearly 20 years.
Polls close at 2 p.m. British time, with results due in the evening.
On the first day of voting, turnout was down slightly at 52 percent, but there was no sign of voters massively shunning the election due to disillusionment with the poisonous political climate, as had been predicted by opinion polls.
A string of scandals and trials, including one on charges that he paid for sex with an underage prostitute, have pushed Berlusconi's popularity to about 30 percent -- the lowest since he swept to power for the third time in 2008.
Berlusconi denies any wrongdoing and says politically biased magistrates are bent on destroying him.
Besides his legal woes, he is also blamed for failing to revive Italy's chronically low growth, while relations with his main ally -- the pro-devolution, anti-immigrant Northern League -- are strained.
The euro zone's third largest economy expanded by only 0.1 percent in the first three months of the year -- badly lagging Germany and France but also crisis-hit Greece.
The League, crucial for Berlusconi's survival after he split from long-time ally Gianfranco Fini, has marked its distance from him on several issues in recent weeks, notably opposing Italy's involvement in the NATO bombing of Libya.
"A VOTE FOR SILVIO"
Berlusconi, who has more than once defeated forecasts of a poor showing at the ballot box, has aggressively hit the campaign trail in the run-up to the polls, turning the election into a vote on him rather than local issues.
"A vote for Silvio" read Sunday's banner headline in Il Giornale daily owned by Berlusconi's brother.
"We are not being asked to judge whether a program is better than another. We are being asked whether we are for or against Berlusconi," wrote Corriere della Sera in an editorial.
Using his trademark mix of jokes, invective against magistrates and opponents, and last-minute electoral pledges, he has stolen the limelight and dictated the political agenda.
Days before the vote, he called prosecutors a "cancer of democracy" and said the opposition "don't wash much."
In Naples, where a long-running waste disposal crisis has reappeared leaving garbage once again festering in the streets, he promised to scrap a rubbish tax until the city is clean.
He also pledged to stop demolishing houses built illegally for a year, a potential vote-winner in a city with a long tradition of building code violations.
The weak centre left, which has so far failed to capitalise on Berlusconi's troubles, hopes to show the tide is turning.
In Milan, its candidate Giuliano Pisapia may have the best chance in years to topple the centre-right city government.
Incumbent mayor Letizia Moratti is seen as vulnerable because of wide middle class disappointment at her failure to modernise the northern city where Berlusconi built his business empire and later launched his political career.
Commentators say that even a run-off in Milan -- let alone Moratti's defeat -- would be a blow to Berlusconi two years ahead of parliamentary elections.
