Welcome to live coverage of stage five of the Giro d'Italia, an undulating 191-kilometre ride from Piombino to Orvieto featuring the famous chalk white roads which last year, in heavy rain, so memorably turned to sludge.

Colnago's Domenico Pozzovivo overshoots a bend and is forced to ride round some road furniture and then under a barrier to get back onto the road. Nice skills.

Kohler is onto the second section of the dirt roads. He has reportedly suffered a puncture though...

Kohler's lead has dropped below the three-minute mark for the first time. It's going to be tight.

Superb descending by Nibali! The Italian has opened up a lead on the front of the peloton thanks to some really dangerous moves on the dirt downhill. Behind him, one rider has unclipped and is using his legs and feet to stabilise himself on the corners. Vintage cyclo-cross racing, this.

Kohler is back onto a small tarmac section. Race radio reports that one of the police motorbikes has toppled over on the descent. With those points atop the two climbs of the day, Kohler has moved above Brambilla in the mountains standings so he'll be rewarded with the green jersey tonight.

This is a very dangerous descent, made all the more difficult with the levels of dust. Kohler will like the fact that he's out in front - it must be hellish sliding around all over these dirt roads as part of a big group or peloton.

Over the top comes the peloton, 3'25" behind leader Kohler. Sky's Peter Kennaugh, riding his first major tour, is in touch with the leaders. Chapeau to the Manxman. Pink jersey David Millar is 20 seconds or so down.

The bunch has been blown apart. Kreuziger leads Scarponi and Garzelli. Nibali and Rodriguez are there, but some of the other big names are feeling the pressure.

Popo is going to be caught, but his move has really opened things up. The road is so dusty. You lose your sun glasses out there and you're doomed. They have reached Popovych. Kreuziger is right up there. He's my tip for the podium this year.

Riders from Astana and Rabobank try to follow Popovych. Scarponi and Rodriguez have moved to the front...

ATTACK: Yaroslav Popovych breaks clear from the peloton. On the front, Kohler is pedalling squares. He's really hit the wall. This is an almighty bonk.

Movistar have moved forward too. The bunch has yet to hit the dirt roads but will do imminently. Kohler is really suffering on the front. But what a stellar ride this has been from the Swiss. He's almost come to a standstill though! This is brutal...

The Astana team of Roman Kreuziger have moved on to the front of the peloton. Kohler's ride has been admirable - and he's holding on for longer than Sean Kelly thought he would.

Besides the dust, the obvious difficulty on these dirt roads are punctures and visibility. They have 19km or so to cover in this first section.

Martin Kohlner (BMC) is currently riding out in front 5'50" ahead of the peloton. The lead was 12'30" but has slowly been whittled down. And he's now onto the dirt roads...

So, here come the white dirt roads - or strade bianchi - of the south Tuscan hills. These roads are not usually used by cyclists - or even cars. They are access roads for the local farmers. Last year, on stage seven to Montalcino, the heavens opened reducing the dirt roads to one big mud bath. This year the sun is out, so the problem will be dust and not sludge. Bring it on...

CRASH: There's a low-speed pile up in the peloton. Quite a few riders are involved, including AG2R's Cyril Dessel and Vacansoleil's Johnny Hoogerland. That has created loads of little splinter groups in the peloton.

Liquigas, Saxo Bank, Lampre and Garmin-Cervelo are all towards the front now. It's a hot day in Italy. At the finish, it's 25 degrees and very sunny.

Kohler is on to the start of the second major climbs of the day. He's struggling now, understandably. The lead is down to 6'44".

Saxo Bank's Richie Porte, the revelation of last year's Giro, was involved in one of those crashes earlier. His team-mates are busy protecting Alberto Contador and so have not been able to help the Australian back to the front. The first of the white dirt road sectors is coming up in seven or so kilometres.

CRASH: Vasili Kiryienka (Movistar Team) comes down after touching wheels with another rider. He's ok, but it shows just how nervous the riders are out there today...