Californian firm Verdant Robotics has developed a new spot sprayer capable of applying chemicals with surgical precision.

The linkage-mounted Sharpshooter will spot, stalk and shoot weeds of any size using novel, turret-like nozzles shaped like hypodermic needles.

Such is their accuracy that it can administer a splodge of spray as small as 17mm and land 95% of the application within 5mm of the target, hitting weeds that would otherwise be safe without resorting to hand rogueing.

See also: Ecorobotix spot sprayer slashes chemical costs by over 90%

Part of the secret to its success is the wiggling action of the nozzles, meaning the longer they stay open, the wider the spread of spray.

This allows it to automatically alter the volume – from 1μl (one millionth of a litre) to 6μl – and pattern according to the diameter of the target, which can range in size from a fingernail to a dinner plate.

And rather than atomising the liquid like a conventional sprayer, precision is further improved by applying a straight stream of herbicide-laced liquor.

As a result, there are no defined droplets and, therefore, practically zero risk of drift.

Working speed is currently limited to 2.7kph, which equates to roughly 120 chemical shots per second.

This is significantly less than the 7.2kph managed by Ecorobotix’s broadly similar Ara – a machine already sold in the UK.

However, Verdant plans to increase it to 3.2kph in the next couple of months, and to 6.4kph – and 480 shots/sec – by the end of next year.

These improvements will increase output from 5ha/hour to nearer 15ha/hour.

Cameras and processing

The super-sophisticated hardware lies beneath an unremarkable-looking hood made from aircraft grade aluminium. On top sits a 500-litre spray tank.

Weed detection starts with a series of conventional RGB cameras that film an area of roughly 100x50cm in 4K+ resolution.

Pairing them with powerful strobes allows them to work effectively by day and night.

The associated artificial intelligence and machine learning software can then identify any unwanted botanicals, based primarily on colour, location and texture.

Herbicide savings are reckoned to be 96-98%, depending on the weed burden.

And, because it weighs just 950kg and can be run on a tractor of just 75hp, the Sharpshooter can operate through extended windows when field conditions are less favourable.

The US company started selling the machines three months ago, having spent the past few years offering the Sharpshooter as a contracting service while it fine-tuned the technology.

Such accuracy and complexity doesn’t come cheap, though. List price of the 20ft model is a cool US$1.2m (£924,000), and custom wide-boom models are significantly more.

There’s also a juicy annual subscription to factor in, ranging from US$50,000 (£38,500) to US$165,000 (£127,000) depending on the number of crop software models required.

However, the company reckons a return on investment can be achieved in as little as two growing seasons.