Image caption Farmers in the Punjab have been worried about water contamination

Sexual confusion does not seem like the most obvious solution to the problem of pest control.

In India, where agriculture accounts for a fifth of one of the world's fastest-growing economies, the question of how to solve the problem of insects destroying a farm's main source of income has resulted in aggressive use of chemicals.

Research in 2008 suggested that farmers in the Punjab - many of whom were spraying their crops every day rather than the recommended couple of times a season - were even becoming more susceptible to cancer.

The solution of one British start-up, Exosect, has been unorthodox, to say the least.

'Surprised'

Philip Howse was looking at different ways of controlling insects while at Southampton University.

He was particularly interested in mimicking the techniques of the carnivorous pitcher plant.

"What if you could somehow persuade loose particles to stick to the adhesive pads on the feet of a fly? Then you could render it helpless, just as the pitcher plants do, and cause it to fall into a trap from which it cannot escape," he says.

Mr Howse realised that you could use the same principles of an electrostatic charge to stick what he wanted to the insects.

Image caption Apples such as these in Herefordshire are being given a second life as extracted nutrients

His 'eureka' moment is the technology behind Exosect, who have pioneered the use of a charged wax powder soaked in female pheromones, which is then attached to the males.

Sprayed in a fog over the crops, it makes the male pests go after other males. "I'm sure they found it a bit of a surprise when it was first used," says Exosect chief executive Martin Brown.

Exosect's electrostatic powder is now being used in the Punjab and west Bengal in India to fight rice stem borers.

"We can control them without the use of insecticides, so we could also avoid knock-on effects, like contaminating the water supply," Mr Brown says.

In addition to India, Exosect's methods are used commercially in apple orchards in England and vineyards in Argentina.

The resulting drop in insect population means that farms have to use about 25 units of pesticides in a hectare, as opposed to up to 1,000 units using traditional means.

Agricultural innovation

The company is one of a number of innovative start-ups working in agriculture around the world.

And the technology has come a long way since the so-called Green Revolution of the 1970s, which focused on using chemical fertilisers and new seeds to boost crop yields and feed ballooning populations in the Third World.

FarmsReach has created an online marketplace to make it easier for buyers such as restaurants and independent supermarkets to buy produce from local farmers.

Water conservation is a key issue for farms, especially in poor nations.

PureSense uses sensors in the ground to monitor how much moisture there is in the soil in real-time, and adjusts the farms' irrigation systems accordingly via wi-fi.

These examples, from California, which has more than 81,000 farms, could be applied on a much larger scale around the world.

Apples revived

Richard Wood, who had worked in pharmaceuticals for most of his career, moved to Herefordshire and was struck by how many apple orchards there were in the county. "There are literally millions of trees," he says.

Image caption The pheromone spray creates a fog of confusion for the insects when it is released

Mr Wood attended a meeting where many local people were worried that lots of trees - many of which have yielded rare apples since the 16th century - would have to be cut down as there was not the same demand as in the past.

"The real value of the apples is the vital nutrients in them," he says. "Some of the most important molecules have properties that block cancer development."

Mr Wood's firm, Coressence, extracts a polyphenol called epicatechin from its apples, which has been shown to relax the arteries of the heart and increase blood flow.

"Epicatechin is also found in cocoa, and apples are two orders of magnitude less expensive than cocoa beans," Mr Wood says.

The firm is planning to launch a range of high-epicatechin juices and drinks next year, as well as a range of skin care products.

Coressence has a partnership with 85 growers of fruit in Herefordshire, and they are also shareholders in the firm.

"It allows them the power to diversify, and it also gives them a bit of marketing power," Mr Wood says.

Other uses

Many of the agriculture start-ups are finding solutions to more than one problem, and find themselves in some interesting places.

In the UK, more than 30% of insecticides are used to control moths.

Exosect's "intelligent" pest control is therefore being used in places like the Houses of Parliament and the Royal Opera House to fight the clothes moth.

The method is also used in chocolate factories to ward off warehouse moths, where the female can lay 350 eggs in their 18-day lifespan.

Image caption Philip Howse came up with the science behind the electrostatic pest control powder

The company has now received a UK government grant to tackle insects in another farm staple, grain storage.

"This is very exciting as it's the first biological solution to the problem," Mr Brown says. "Around 16% of the world's grain is destroyed by insects in storage."

And the company is also turning its attention to bees, which have suffered in recent years from an alarming fall in numbers.

"Bees just happen to be the most electrostatic insect of all," Mr Brown notes.