Apart from sprayers, the DLG Feldtage 2026 event in Germany had a great array of weed control methods, from mechanical weeding to laser systems. These alternatives have serious disadvantages, in terms of cost and effectiveness, compared to spray-based systems, so why are we interested?

There are many reasons. Weeds, pathogens which cause disease and pests are evolving to become resistant to the pesticides we use. While this is a normal development, it is happening more easily with modern pesticides, which are safer to health and the environment, and it is occurring in more critical species. This includes blackgrass, Italian ryegrass in cereals and blight in potatoes.

Also, there are fewer new pesticides being registered, as development and registration become more difficult and expensive. In addition, organic growers need viable alternatives to labour-intensive and menial, manual weeding.

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But the path to alternatives is not easy with the only certainty being that development will continue. The rush to invest in alternatives by technology funds for high-tech ideas and by the machinery industry for inter-row mechanical weeding companies, is unlikely to yield quick returns.

This area is a relatively ‘slow burn’ that will require continued investment and, more importantly, research support.

1.Conventional sprayers

A full suite of conventional sprayers with all the latest control technology was on view in the test arena and also on commercial stands. The test arena had four specific areas (similar to the Teagasc/Irish Farmers Journal Crops and Technology 2025), which allowed spectators and the commentary team to evaluate:

  • Boom suspension: a track within the crop featuring both a left-right slope and a bumpy section was used to test boom stability, which is hugely important on wide boom sprayers.
  • Curve control: spraying around a curve to demonstrate the ability of the nozzle control system, to vary the output at individual nozzle points to maintain a constant application rate.
  • Boom section control: an angled line was used to create an area for the section control to work on.
  • Spot spraying green on brown: a number of approximately 1m2 of green foliage were placed in the sprayer path, with most demo operators choosing to ‘map’ these in advance of spraying, mimicking using a drone or similar to find the weed areas in advance of spraying.

    • Most of the sprayers had the technology to perform well in all of these tests. Height sensors on the booms kept the nozzle height constant in most cases.

    However, the suspension of some of the sprayers was challenged a little on the bumpy track, where forward/backward whipping of the boom (known as yaw) would have impacted on application evenness at the boom outer sections.

    Both pulsing nozzles (PWM) and rapid switching nozzles were visually coping with the curve – however, a precise measurement rig would be needed to determine how effective they were.

    There were differences in the spot spraying, however, some hitting the patches spot-on, while others clearly missed the patches indicating a need for a ‘ground truthing’ check system to be built into commercial systems.

    This Agrio sprayer from Czechia had all of the top specifications, but was manufactured with a lot of universal or common components in terms of pumps,valves, pipework, etc. It also used pneumatic control for nozzle switching (curve control) in preference to electronics at the individual nozzles. It performed well in the spraying arena.

    2. Precision weeders: lasers and high-precision spot sprayers

    In the robotic/technology area, both high-precision spot sprayers and laser weeders were demonstrated. The high-precision sprayers consist of a hooded canopy, typically about 6m wide, which houses a bright light and camera system that captures high-resolution images of the weeds/plants.

    It then uses an AI system to instantly identify and accurately position the weeds, which are then individually sprayed with herbicide by fast solenoid nozzles at spacings of just 4cm.

    There are a number of these sprayers available now.

    The ARA high precision sprayer, which is on the market for a couple of years now, uses a hooded design for strong lighting and high resolution image capture. It’s a 6m unit with 4cm nozzle spacing and the capacity to target 6cm x 6cm areas. At a forward speed of 7kmh it can precision spray up to 4ha/hr.

    Where targets are more easily identified and where crop safe selective herbicides are used (eg dock control in grassland), a simpler set-up without hood or lights can suffice.

    These can greatly reduce the amount of herbicides needed to control docks.

    Laser weeders are currently the ‘great hope’ in precision weed control.

    This Escardo laser weeder, 1.4m for working in a bed system, is fitted with two laser modules requiring about 7 kW electrical power. The German start-up company which developed the unit have recently been taken over by a much larger specialist in laser use (B.I.G) who are in the process of scaling up and developing the technology for use in agricultural environments. There are a number of other player in this area: A NAITURE (Germany) unit was also shown at a static stand at the DLG while Carbon Robotics (US) and Earthrover (UK) among others are active in this area.

    The weed identification element of these units is similar to that in the high-precision sprayer mentioned above (hooded section with lights and camera sensors), but the identified plants are then targeted with laser energy to effectively burn the plant.

    This differs from the direct electrical energy contact system used in Ireland to desiccate potatoes, for example, which cannot target individual plants.

    At the moment, cost, complexity and speed are major constraints for high-precision spot-spraying and, particularly, for laser weeding. They are currently marketed to growers of high-value organic crops. However, if the availability of effective herbicides continues to decline, with further development, they may have broader application in the future.

    The two laser units can be seen beneath the hood of the Escardo weeded.

    3. Mechanical weeding demonstration

    Mechanical crop-weeding demonstrations were carried out in two crops. Maize (25 to 35cm tall) was used to demonstrate auto-steering, inter-row weeders. A very late-sown barley crop at early tillering stage was used to demonstrate tine weeders.

    In the row-crop section, all machines used cameras to guide the weeders down the rows. The different makes showed different cultivation tools, but most had one or two vertical tines in the non-crop area, with either horizontal finger wheels or vertical serrated discs working closest to the crop plants. The individual models differed in frame design, the individual hoeing units and their cultivation elements, and in the ease of adjustment of the hoeing elements.

    The APV unit was typical of many interrow cultivators with a camera for guidance on the aluminimum section at the left side of the unit to ensure the weeder runs straight down the row. Each weeding unit (yellow)

    The Kverneland tine weeder was similar in principal most of the tine weeders shown working in barley. While the barley was relatively undamaged, there wasn’t a serious weed challenge visible in the crop.

    For optimal weeding, these elements would be adjusted when changing fields/crops so rapid adjustment might increase the chance of the operator doing it.

    The manufacturers who exhibited included: Amazone, APV, Einbok, Horsch, Kubota (Kverneland), Kult (Fyeld), Treffler and Garford.

    In the barley section, simple tine weeders were used without steering systems. These weeders varied in tine type and the pressure adjustment system that was used. Machines were demonstrated by APV, Horsch, Kverneland, Dickson, Kuhn, Lemken and Pottinger.

    Overall, while the demonstrations allowed attendees to see the machines’ features and operation, both crops were very clean. To gauge effectiveness, it would be useful to see crops that had weed challenges that had been weeded weeks earlier. It is probably easier to operate a mechanical weeder in drier climates than Ireland’s. Frequent wet weather would make optimum timing difficult.

    Some of the line-up of the 7 camera-guided in-row weeders used at the DLG demo