Look out weeds. Tractor giant John Deere just spent $305 million to acquire a startup that makes robots capable of identifying unwanted plants, and shooting them with deadly, high-precision squirts of herbicide.

John Deere, established in 1837 to manufacture hand tools, announced it had acquired Blue River Technology, founded in 2011, late Wednesday.

Deere already sells technology that uses GPS to automate the movements of farm vehicles across a field to sub-inch accuracy. John Stone, an executive in the company's intelligent-solutions group, says Blue River’s computer-vision technology will help Deere's equipment view and understand the crops it is working with. “Taking care of each individual plant unlocks a lot of economic value for farmers,” Stone says.

The deal highlights the growing appetite for high tech in agriculture. Many companies are using drones to help farmers by collecting data on crops to plan spraying or other operations. Stone says that Blue River’s technology can make a larger impact on productivity because it makes decisions up close, on the ground.

Pesticides and other chemicals are traditionally applied blindly across a whole field or crop. Blue River’s systems are agricultural sharp shooters that direct chemicals only where they are needed.

The startup’s robots are towed behind a regular tractor like conventional spraying equipment. But they have cameras on board that use machine-learning software to distinguish between crops and weeds, and automated sprayers to target unwanted plants.

The company says its first product, LettuceBot, already has a hand in roughly 10 percent of US lettuce production. It is used on fields with young lettuce plants, targeting weeds as well as plants that are too small, or growing on top of one another.

This season Blue River tested a second system for cotton farmers, ahead of a planned commercial launch in 2018. That system can target weeds with squirts of herbicide no larger than a postage stamp. Willy Pell, director of new technology at Blue River, says the system has shown it can reduce herbicide use by 90 percent.

Blue River, which has roughly 60 employees, will operate as an independent brand, from its base in Sunnyvale, California. Pell says that the company plans to develop versions of its technology for other crops such as soybeans and corn. Blue River also wants to deploy its computer-vision software in harvesting and seed planting equipment so it can adapt to variations in the size of soil clods or corn plants across a field.