By Richard Hamilton BBC, Antalaha

Madagascar is well known for its exotic spices particularly vanilla.

Vanilla prices have gone through the roof

But now the price of vanilla has hit its highest peak in history and is causing an outbreak of robberies and even killings in the vanilla growing region.

In the heart of this region is the town of Antalaha. It lies on the north-east coast of Madagascar and offers classic postcard views.

There are long palm trees that bend over a golden beach which stretches out for miles and then in the distance the waves are breaking over the coral.

Beyond the palm trees I can see white tall buildings.

They are the villas of the vanilla barons - people who have made money out of this rare orchid.

Supplies

But the plant has brought both good and bad to the town.

Three years ago, Cyclone Hudah destroyed more than 20% of Madagascar's vanilla crop and because the orchids take three years to flower the result has been a shortage of supply this year and an escalation in price - up to $200 per kilogramme.

The factory owners are afraid. Often they sleep with guns by their bedsides, but they no longer sleep. Agronomist Hery

The agronomist at the largest vanilla plant in Antalaha is called Hery.

He says the high price has led to a spate of robberies and attacks. He told me that a month ago three people from one family were killed.

"People will even attack members of their own family. It's incredible. You have to choose carefully your security guards because otherwise they collaborate with the vanilla thieves. And they must be armed because the thieves attack with guns.

"It's not like the good old days when people just fought by hand. Vanilla is a big prize for a thief. The factory owners are afraid. Often they sleep with guns by their bedsides, but they no longer sleep."

Crime

The bustling market of Maroantsetra lies further down the vanilla coast.

Here I met Solange whose family has been in the trade for many years. She too said crime had escalated commensurably with the price of vanilla:

"It's really terrible what is happening because it is at all levels. There are thefts, assassinations and a lot of corruption. There is always a risk of being robbed.

"People are afraid to go out of their homes. If you leave your home you can get robbed and if you don't leave your home you can be killed. I have heard of one case where someone came into a house with a gun to rob a family and he was shot in the neck."

Tim Ecott, who is researching a book about vanilla, said that from a purely business point of view the current high price could bring problems for manufacturers, even though the vanilla growers are cash-rich at the moment.

"The problem is that in the industrialised nations - particularly in the United States where most vanilla is used - in things like ice cream and biscuit making - industrial manufacturers want to keep their costs down," he said

As soon as something that was an essential natural ingredient rises by that amount, he says, they will look around for an artificial substitute whose price can be controlled.

"If this high price continues for too long people will look for an artificial substitute."

Many of Madagascar's vanilla farmers are realistic - they know they are experiencing a boom which will inevitably become a downturn.

But if it means thefts and killings along the vanilla coast also experience a decline, they won't be disappointed.