Targeted Weeding
Targeted weeding allows applying herbicide only on the targeted weeds within a crop. With this technique, one reduces herbicide use, notably by avoiding blanket treatments. Targeted weeding is all the more interesting since some selective products are costly.
The treatment can be done at several scales: on a strip, on a row, or on a detected weed.
How localized row spraying works
This technique consists of localizing chemical weeding on the crop row, thanks to specific nozzles (conical or uniform spray types are preferred) which must spray precisely, limit drift, and cover the strip without overlap. It can be applied:
- for pre-emergence weeding, by mounting a localized treatment boom on the seeder
- for mixed post-emergence weeding, by adapting a localized treatment boom on a hoeing machine (weed hoe)
- for localized chemical post-emergence weeding, by using a localized spraying boom alone.
Localized row spraying is complemented by mechanical inter-row weeding.
Suitable crops
Localized row spraying is used on crops grown in clearly visible rows and whose inter-row can be managed mechanically.
How targeted spraying works
This technique is more precise because it allows spraying herbicide only on the weed. Targeted spraying relies on sensors, cameras, and artificial intelligence.
Targeted spraying can be immediate or deferred (based on prescription maps).
Sensors and cameras
Sensors and cameras can be mounted on the sprayer boom or on drones.
Depending on the tools, distinctions between cash crops and weeds or between soil and weeds can be based on:
- Reflectance, an index quantifying the light flux reflected by the plant relative to the light flux it received. Each plant has its own spectral band, allowing recognition. Infrared rays inform about the internal structure of leaves, while visible rays estimate plant biomass.
- Chlorophyll fluorescence specifies weed biomass
- the images obtained by cameras.
Data analysis
Deferred spraying
From data collected by sensors and cameras, pixelated maps of the plots are created, called prescription maps. These must then be decoded by artificial intelligence and loaded into the device that will spray the herbicide later, hence deferred spraying.
Immediate spraying
In the case of immediate spraying, data are analyzed and processed as soon as they are captured. An action response is then implemented within seconds for the sprayer. The analysis system relies on artificial intelligence integrated into the sprayer.
Spraying
| Immediate spraying | Deferred spraying | ||
|---|---|---|---|
| Advantages |
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| Disadvantages |
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Drone
Flight authorization required |
Tractor-mounted camera
Two passes over plots required |
The prescription map can be used on any sprayer equipped with GPS, section control, and an unlocked console for modulation (option cost between €500 and €1500). This technique therefore does not require buying new equipment; however, correct interpretation of the map by the sprayer depends on the tool's parameters, which must have good boom stability and a responsive regulation system.
It is also recommended to equip the sprayer with PWM nozzle holders (Pulse Width Modulation) capable of controlling nozzle opening/closing and modulating the dose delivered by the nozzle.
Cost
According to trials conducted by the Chamber of Agriculture of Somme, which uses a drone for deferred targeted weeding, herbicide application costs €23/ha (€15 for weed detection and €8 for herbicide) instead of €40/ha for blanket weeding. Savings from targeted weeding depend, however, on the infestation level of the plot and the section width.
For a machine like Ecorobotix's Ara[1] which performs immediate targeted spraying, the machine cost ranges between €164,493 and €217,990. According to the company, the return on investment occurs in 2 to 4 years depending on the farm size.
Advantages of localized or targeted spraying
- Strong reduction in applied volumes, thus reduced environmental impact.
- Financial savings.
- Less stress or growth slowdown for cash crops.
Limitations
- Investment cost in equipment (especially for targeted spraying).
- Longer treatment time because equipment must be precisely adjusted, prescription maps created for deferred spraying systems, and time allowed for algorithms to process data for immediate spraying systems (implying reduced sprayer speed in the field).
Market tools
| Feature | Ara (Ecorobotix) | Smart Sprayer | Sniper | I-SPRAY (Kuhn) |
|---|---|---|---|---|
| Immediate or deferred treatment? | Immediate | Immediate | Immediate | Deferred |
| Technology type | Ultra-high precision mounted sprayer with AI Plant-by-Plant | Cameras + AI + xarvio™ agronomic decision | Cameras + AI for weed detection | Hyperspectral sensors + AI integrated into sprayer |
| Weed detection | RGB + 3D cameras, AI to distinguish weeds vs crops | High-resolution Bosch cameras, vegetation recognition | Cameras and algorithms detect weeds (green on brown and green on green) | Hyperspectral sensors continuously analyze vegetation |
| Spraying mode | Plant by plant (6×6 cm) | Localized in real-time according to predefined thresholds | Localized based on detection | Localized + potential modulation based on biomass |
| Product reduction | Up to 80-95% depending on conditions | Up to 70-90% according to trials | Up to 70-90% (depending on detected technology) | Up to 95% possible (depending on targeted application) |
| Sensors and lighting | Yes – 6 camera modules, integrated AI | Yes – cameras + LED lighting | Yes – cameras + AI | Yes – hyperspectral sensors |
| Green on green treatment (crop-weed distinction) | Yes (distinguishes weeds even close to crops) | Yes, continuous analysis | Yes – recognizes crops and weeds | Yes – capable of various green on green and green on brown strategies |
| Agronomic decision system | Embedded AI Plant-by-Plant | AI + xarvio platform for thresholds and dynamic decision | Embedded AI | AI with hyperspectral analysis (and future platform integration) |
| Commercial maturity phase | Commercialized and in use | Available / progressive commercialization | Developed and field tested | Concept tested, limited initial equipment |
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Sources
- ARVALIS. 2025. Targeted weeding: equipping a sprayer becomes profitable from 25% treated area. [28/01/2026]. https://www.arvalis.fr/infos-techniques/desherbage-cible-equiper-un-pulverisateur-devient-rentable-des-25-de-surface
- Christelle Gée, Gawain Jones, Thibault Maillot, Jean-Noël Paoli, Sylvain Villette. 2018. Precision weeding. [28/01/2026]. https://www.researchgate.net/profile/Christelle-Gee/publication/325463660_Chapitre_26_Le_desherbage_de_precision/links/5da0699245851553ff870588/Chapitre-26-Le-desherbage-de-precision.pdf
- Paysan Breton. 2025. Camera-based targeted spraying in retrofit mode. [28/01/2026]. https://www.paysan-breton.fr/2025/01/la-pulverisation-ciblee-par-cameras-en-mode-retrofit/
- Réussir. 2021. Targeted weeding, an innovation to reduce herbicide IFTs. [28/01/2026]. https://www.action-agricole-picarde.com/le-desherbage-cible-une-innovation-pour-reduire-les-ift-herbicides
- Syngenta. 2023. Targeted spraying, a promising technique. [28/01/2026]. https://www.syngenta.fr/agriculture-durable/bonnes-pratiques-agricoles/article/pulverisation-ciblee-technique-prometteuse
- Terre nature. 2025. Ecorobotix: the flagship of precision weeding. [28/01/2026]. https://www.terrenature.ch/hors-serie/ecorobotix-le-fleuron-du-desherbage-de-precision/
- ↑ Terre nature. 2025. Ecorobotix: the flagship of precision weeding. [28/01/2026]. https://www.terrenature.ch/hors-serie/ecorobotix-le-fleuron-du-desherbage-de-precision/
