C‑DRONE
Agricultural drone flying over a farm field

C-DRONE GUIDE · 31 AUGUST 2026

Flavescence Dorée: Drone Detection, Mandatory Uprooting and the Control Calendar

Since late August, rows of vines have been turning red or yellow in patches, leaves curling, canes staying green and supple instead of ripening. It isn't always a nutrient deficiency or bois noir. If the plot sits in a delimited zone, these symptoms may signal flavescence dorée, an incurable phytoplasma spread by a leafhopper, whose control is mandatory under a national order and translates, every year, into three compulsory insecticide treatments, a field survey across the whole symptomatic window, and, beyond a contamination threshold, the complete uprooting of the plot. On a large estate or for a pest-control group, walking every row before leaf fall is a race against time. Here is what the regulation says, what the research shows about drone-based detection, and how an imaging campaign is planned and priced.

Published on 31 August 2026, reviewed on 1 September 2026 — regulations in force as of September 2026.

A quarantine disease, not an agronomic choice

Flavescence dorée is caused by a phytoplasma, a cell-wall-free bacterium of the Mollicutes class, transmitted from vine to vine by the bites of a leafhopper, Scaphoideus titanus. Once a vine is infected, no treatment cures it: the plant declines over several years and, as long as it stands, remains a reservoir that lets the vector insect infect neighbouring rows. That absence of a cure is what justifies a mandatory control regime, distinct from ordinary agronomic advice: the disease is not managed at the scale of a single vine, but at the scale of the whole vineyard.

The national framework is set by the order of 27 April 2021 on the control of flavescence dorée of the vine and its vector agent, which replaced the 19 December 2013 text, itself derived from an original 2003 order. Every year, a prefectural order — regional or départemental depending on the territory — delimits the communes classified as a mandatory control zone based on the outbreaks recorded the previous year: in Occitanie, the order of 11 May 2026 sets the perimeter for the current campaign; in Pays de la Loire, the order of 21 May 2026 does the same. Within those communes, every grower, organic farms included, is subject to the same survey, declaration and treatment obligations, with no exemption tied to farm size.

One point of vocabulary matters: flavescence dorée looks, to the eye, almost identical to bois noir, a phytoplasma yellows disease with nearly the same symptoms but carried by a different insect and not subject to the same regulation. Only a laboratory analysis — PCR on a sample — tells the two apart with certainty. Any suspicion must be reported to the regional pest-control federation (FREDON) or the regional food service (SRAL), which organises the sampling.

Three mandatory treatments, a survey window that is open right now

In a classified commune, the fight against the vector is chemical and scheduled: three insecticide treatments are mandatory every season on all vine plots, including new plantings from their very first year, whatever the training system. The first targets larvae about a month after hatching, before they become infectious; the second follows some two weeks later, at the end of the first product's period of action; the third targets adults. The precise dates, specific to each zone and set from field observation of the leafhopper's stages, are published in a DRAAF-SRAL bulletin and apply to every grower in the perimeter — they are not negotiated case by case. Along watercourses, the no-treatment buffer for these applications is reduced to 5 metres, or 3 metres with certified equipment cutting drift by at least 90%.

The second, less well-known obligation is surveying: every plot in a delimited zone must be walked in search of symptoms, and any outbreak reported to the SRAL. But flavescence dorée is only visible at a precise point in the cycle: leaves turn red (black varieties) or yellow (white varieties) and curl downward, canes stay green and supple instead of ripening, typically from late summer into early autumn — the window is open right now and closes as natural leaf senescence sets in, quickly blurring the signal. On a large estate, or for a pest-control group that has to cover several hundred hectares in a few weeks, that calendar constraint weighs more heavily than the technical difficulty of the diagnosis itself.

Mandatory uprooting: the 20% threshold, abandoned vines within 250 m

Any vine showing symptoms must be uprooted, marked and destroyed: that is the baseline rule, applicable from the very first vine identified. It changes scale beyond a precise threshold: once the rate of contaminated or symptomatic vines in a plot, cumulated over a maximum of three consecutive seasons, reaches or exceeds 20%, the entire plot must be uprooted and destroyed, including any still-healthy vines it contains. That threshold turns a localised health issue into a heavy economic decision: immediate loss of production potential, replanting pushed back several years, and, for an appellation, a challenge to the replanting right over areas that are sometimes classified. Hence the value, for a grower or a pest-control group alike, of spotting outbreaks as early as possible, before they spread far enough to cross that threshold.

A second, less visible obligation concerns uncultivated or abandoned vines: in a delimited zone, a plot left fallow within 250 metres of an outbreak or a mother-vine plot can be ordered uprooted by the prefect, following a SRAL risk analysis, even if its owner no longer farms it. Such fallow plots, invisible in harvest declarations, are nonetheless one of the main reservoirs feeding a sector's reinfestation from one year to the next — a point that field bodies, chambers of agriculture chief among them, document regularly.

An uprooted plot then needs recounting to prepare replanting: our guide to counting missing vines by drone covers that step, distinct from detection itself.

What the research shows, and how to organise a campaign

The idea of aerial-imagery detection is not new: as early as 2017, H. Al-Saddik, J.-C. Simon and F. Cointault published in Sensors a study building spectral disease indices specific to flavescence dorée from leaf-by-leaf hyperspectral measurements, reaching a correct classification rate close to 90% — proof that a disease-specific spectral signature exists and stands out from ordinary agronomic noise (see the study on Google Scholar). The remaining question was whether that signal, measured against the leaf, still shows up from a drone flying over a whole plot.

That is the question a Toulouse-based team — J. Albetis, S. Duthoit, F. Guttler and co-authors, published in 2019 in Remote Sensing — asked over two South-West French vineyards, the Gaillac and Minervois AOCs. More than 900 vines were geolocated by centimetre-accuracy GPS and classified on the ground (218 asymptomatic, 502 affected by flavescence dorée, 199 by trunk diseases), before being surveyed by a drone fitted with a MicaSense RedEdge multispectral sensor (see the study on Google Scholar). The result: separating healthy from symptomatic vines works markedly better on red varieties than on white ones, where infected leaf colouring stands out less against healthy foliage — an important technical limit to know before commissioning a campaign on an estate planted with white grapes.

What these two studies cautiously support: a multispectral drone pass, flown within the symptomatic window and read with the right indices, lets you prioritise ground surveying across a large plot — spotting high-suspicion areas in one morning rather than walking dozens of hectares uniformly on foot. It does not replace the regulatory survey or the declaration to the SRAL, which remain human, legally binding acts; it lets you concentrate them where they are most likely to confirm an outbreak.

A campaign is priced like other multispectral vine monitoring: for a plot of 10 to 30 ha, expect €500 to €900 excl. VAT per pass, index maps included — the detail by area and monitoring frequency sits in our guide to thermal and multispectral vine monitoring. The difference lies in the calendar: this flight cannot wait — it has to be booked in the next few weeks, before leaf fall closes the window. On plots where an outbreak is confirmed, carrying out the three mandatory insecticide treatments remains, in the vast majority of cases, ground-based work; on steep-slope plots covered by the biocontrol derogation, a drone can sometimes handle it if the chosen product qualifies — a separate framework covered in our guide to drone spraying in vineyards. For a detection campaign on your estate or on behalf of a pest-control group, request a quote stating the area, the grape variety and your preferred flight date.

Request a free quote

Put it into practice

Also worth reading