Weed control technology - what are the latest developments?

Up to now, herbicide use has been the solution to weed problems, but for a multitude of reasons, this is changing and the focus is now on development of integrated control measures where herbicide use is minimised.

This approach will continue as herbicide resistance increases, new herbicide introductions fall, and a desire for less pesticide use grows among the general population.

While some crops can be managed to reduce weed development and growth, through crop choice, time of sowing, seeding rate, row spacing and other management strategies; in most cases significant weed development will still occur and weed destruction will still be required.

There are three categories of post emergence weed destruction that can be used as part of integrated weed control strategies:

Mechanical weed control and targeted application of herbicides were featured strongly at Agritechnica 2023.

Mechanical weed control

The majority of cultivation equipment manufacturers displaying at Agritechnica have acquired expertise and developed machines either in-house or through the acquisition of smaller companies that were specialising in this area.

There are a range of technologies in this area varying in sophistication. These include:

Many of these technologies were shown at the 2023 Crops and Cover Crops Open day at Oak Park in June.

While mechanical weeders will have a role to play, their complexity and operational cost increases rapidly as more effective weeding is required and the need for continuous shallow soil working can also be quite hard on the soil.

Challenge

Perhaps most challenging of all though, in a wetter climate like ours, is whether the weeds will quickly recover, as mechanical weeders may be more effective in dry climates.

Getting the timing right in our conditions, to knock out the weeds, prevent soil damage and avoid weed regrowth, could be challenging.

But we have used basic versions of these systems before, mainly as steerage hoes; no doubt we can do it again if conditions demand it.

Spot spraying of weeds

The second weeding technology, where there were significant developments on display at Agritechnica, is spot-spraying, where weeds are only sprayed where they are identified.

The concept of identifying and spraying weeds has been around for at least 30 years, but bringing it to reality has been a slow process; but progress is being made.

All of these systems use similar weed sensing approaches using one or more camera type sensors; either RGB (visible spectrum) or multispec sensors (additional non-visible wavelengths) to help identify the weeds or weedy areas.

But there is a huge difference in the capabilities and precision with which different versions of this technology operate.

Currently the technology can largely be divided into three categories: