C-DRONE GUIDE · 11 SEPTEMBER 2026

Sugar beet and drones: virus yellows and Cercospora leaf spot, price

Sugar beet covered 411,766 hectares in France in 2024, mostly in Hauts-de-France (200,125 ha, nearly half the national area) and Grand Est (115,296 ha) — a sector still living in the shadow of the 2020 crisis, when the end of neonicotinoid protection sent average yields down 28% under pressure from virus yellows. Since derogations were definitively shut down in 2023, confirmed by the Court of Justice of the European Union and then the Conseil d'État, the sector has leaned on tolerant varieties, biocontrol and stepped-up monitoring. Here is what two recent studies document on drone detection of virus yellows and Cercospora leaf spot — and where a flight genuinely fits into that strategy.

Published on 11 September 2026, reviewed on 12 September 2026 — regulations in force as of September 2026.

A sector still reeling from the virus yellows crisis

Sugar beet remains a major industrial crop in northern France: 411,766 hectares in 2024, production of 34.38 million tonnes (+6.3% year on year), and a 2025 estimate of 397,522 hectares (-3.4%) with an average projected yield of 89 tonnes/hectare, for 35.5 million tonnes of production (+9% year on year, +15% above the 2020-2024 average). Hauts-de-France accounts for 200,125 hectares, nearly half the national area, ahead of Grand Est's 115,296 hectares.

The sector still carries the scars of the 2020 crisis: the ban on neonicotinoid-treated seed, enacted by the 2016 biodiversity law and effective from 1 September 2018, stripped growers of their main protection against the aphids that spread virus yellows. The result: an average yield drop of 28% across the entire French sugar-beet area in 2020. A law passed on 14 December 2020 authorised a temporary, three-season derogation (treated seed in 2021 and again in 2022), before the Court of Justice of the European Union, on 19 January 2023, and then the Conseil d'État, on 3 May 2023, definitively closed that option. Since 2023, no neonicotinoid seed treatment has been authorised at all: the sector is banking on virus-yellows-tolerant varieties now going through CTPS registration (seed breeders KWS and SESVanderHave), on biocontrol, and on an aphid-trapping network to trigger interventions.

What two studies document by aerial imagery

Two recent studies, both carried out in Germany by teams specialised in sugar-beet plant pathology, document directly what a drone detects on this exact crop — with no need to extrapolate from another species. Okole, Ispizua Yamati, Hossain, Varrelmann, Mahlein and Heim, in a study published in 2024 in Plant Pathology, assess low-altitude aerial remote sensing and deep learning for scoring virus-yellows incidence across more than 120 plots, benchmarked against counts by three ground experts (see the study on Google Scholar). The authors note that symptoms of beet chlorosis virus (BChV) are less pronounced than those of beet mild yellowing virus (BMYV): a drone alone therefore cannot reliably tell the two viruses behind virus yellows apart, and laboratory confirmation remains necessary.

Sugar beet's second summer threat, Cercospora leaf spot (Cercospora beticola), was documented by Barreto, Ispizua Yamati, Varrelmann, Paulus and Mahlein in a study published in 2023 in Plant Disease (see the study on Google Scholar). On an inoculated variety trial tracked across the whole season with an onboard multispectral camera, the authors show that adding the digital surface model, vegetation indices and shading conditions to spectral channels alone markedly improves classification between diseased areas and bare soil.

What a flight brings to a grower or a sugar mill — and what it does not replace

Two uses stand out for a farm or a sugar-beet cooperative. The first is mapping virus-yellows foci, which typically spread outward in an oil-slick pattern from an initial infestation point: a multispectral flight in early summer objectively captures a focus's extent and progression, useful for comparing tolerant varieties under trial or for documenting a loss to a crop insurer. The second is early spotting of Cercospora leaf spot, favoured by the warm, humid summers of late season: a vigour map targeting emerging foci before widespread defoliation helps prioritise field rounds and target fungicide application on genuinely affected zones rather than spraying blanket.

Two limits worth knowing. First, a drone cannot reliably distinguish the two viruses behind virus yellows (BMYV, more symptomatic, and BChV, more discreet): only a laboratory analysis (ELISA or PCR) confirms the agent involved. Second, a flight does not replace the national aphid-trapping network run through the Bulletin de santé du végétal, which remains the reference tool for triggering an intervention during sugar beet's sensitive window (2 to 12 true leaves): by the time virus yellows becomes visible from the air, the virus has already been transmitted. A drone's value therefore lies mainly in variety evaluation, loss assessment and anticipating Cercospora — not in triggering the spring treatment decision.

Where to fly in Hauts-de-France and Grand Est

Most sugar-beet plots sit on flat terrain with no significant relief, in zones falling very largely under the open category, subcategory A3. The point worth checking before any flight is the proximity of an aerodrome or a temporary restricted zone: in Aisne and Somme, the heart of the Picardy basin, a practical base is Saint-Quentin, with a systematic check on the Géoportail drone zone map; our regional guide to drone missions in Hauts-de-France covers the full airspace picture across the five departments. In Marne, another major beet-growing area, missions are coordinated from Châlons-en-Champagne; our guide to drone missions in Grand Est covers the region's specific constraints, between military zones and nearby nuclear sites.

This virus-yellows and Cercospora mapping happens on established vegetation, between June and August: it is distinct from emergence counting, which targets the seedling stage to decide on replanting as early as spring. Our page on precision agriculture by drone covers the multispectral method across all types of row crops.

Prices observed in 2026

A sugar-beet plot is priced mostly on a targeted campaign, on established vegetation. Ranges observed in France in 2026, excl. VAT:

Service	Range (excl. VAT)
Multispectral virus-yellows scouting flight (up to 10 hectares)	€280 to €500
Multispectral Cercospora scouting flight (up to 10 hectares)	€280 to €500
Additional pass per extra 10-hectare block	€80 to €140
Combined seasonal monitoring (2 to 3 passes, virus yellows + Cercospora)	€650 to €1,050

These amounts cover the flight and delivery of a usable map within 24 to 48 hours; they do not include laboratory confirmation of the viral agent, crop-protection treatment, or aphid trapping, which remain the responsibility of the grower, their sugar cooperative or the Bulletin de santé du végétal network. For a growers' group working with the same sugar mill, a pooled campaign across several neighbouring plots meaningfully cuts the cost per hectare. Request a quote stating the area, the number of plots and the intended period: June-July for virus yellows, July-August for Cercospora.

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