In a field of sugar beet in Switzerland, a solar-powered robot that looks like a table on wheels scans the rows of crops with its camera, identifies weeds and zaps them with jets of blue liquid from its mechanical tentacles. Undergoing final tests before the liquid is replaced with weedkiller, the Swiss robot is one of new breed of AI weeders that investors say could disrupt the $100 billion pesticides and seeds industry by reducing the need for universal herbicides and the genetically modified (GM) crops that tolerate them. Dominated by companies such as Bayer, DowDuPont , BASF and Syngenta, the industry is bracing for the impact of digital agricultural technology and some firms are already adapting their business models. The stakes are high. Herbicide sales are worth $26 billion a year and account for 46 percent of pesticides revenue overall while 90 percent of GM seeds have some herbicide tolerance built in, according to market researcher Phillips McDougall.

"Some of the profit pools that are now in the hands of the big agrochemical companies will shift, partly to the farmer and partly to the equipment manufacturers," said Cedric Lecamp, who runs the $1 billion Pictet-Nutrition fund that invests in companies along the food supply chain. In response, producers such as Germany's Bayer have sought partners for their own precision spraying systems while ChemChina's Syngenta, for example, is looking to develop crop protection products suited to the new equipment. While still in its infancy, the plant-by-plant approach heralds a marked shift from standard methods of crop production.

Now, non-selective weedkillers such as Monsanto's Roundup are sprayed on vast tracts of land planted with tolerant GM seeds, driving one of the most lucrative business models in the industry.

But ecoRobotix, developer of the Swiss weeder, believes its design could reduce the amount of herbicide farmers use by 20 times. The company said it is close to signing a financing round with investors and is due to go on the market by early 2019.

Blue River, a Silicon Valley startup bought by U.S. tractor company Deere & Co. for $305 million last year, has also developed a machine using on-board cameras to distinguish weeds from crops and only squirt herbicides where necessary. Its "See and Spray" weed control machine, which has been tested in U.S. cotton fields, is towed by a tractor and the developers estimate it could cut herbicide use by 90 percent once crops have started growing.

German engineering company Robert Bosch is also working on similar precision spraying kits as are other startups such as Denmark's Agrointelli. ROBO Global, an advisory firm that runs a robotics and automation investment index tracked by funds worth a combined $4 billion, believes plant-by-plant precision spraying will only gain in importance.

"A lot of the technology is already available. It's just a question of packaging it together at the right cost for the farmers," said Richard Lightbound, Robo's CEO for Europe, the Middle East and Africa.

"If you can reduce herbicides by the factor of 10 it becomes very compelling for the farmer in terms of productivity. It's also eco friendly and that's clearly going to be very popular, if not compulsory, at some stage," he said.

The advent of precision weed killing also comes at a time blanket spraying of global blockbusters such as glyphosate is under fire from environmentalists and regulators alike. More than 20 years of near-ubiquitous use of glyphosate, the active substance in Monsanto's Roundup, has created resistant strains of weeds that are spreading across the U.S. farm belt. Regulators have raised the bar for bringing blanket chemical agents to market and the fear of toxic risks has been heightened by the debate over the potential impact of glyphosate on health. Michael Owen, associate chair at Iowa State University's Department of Agronomy, reckons it would now cost agrochemical giants up to an almost prohibitive $400 million to develop a next-generation universal weedkiller.