C-DRONE GUIDE · 8 SEPTEMBER 2026

Hops and hop yards by drone: vigour, downy mildew, multispectral mapping, price

In Alsace, on the plain around Haguenau, hop yards form a vertical landscape found nowhere else in France: rows of roughly 7 m poles supporting foliage that climbs 6 to 10 m between April and June. Driven by the rise of craft breweries, the French hop industry is growing at a pace rare for a niche crop — but the very height that sets it apart also complicates monitoring: the most exposed part of the foliage, where vigour and early downy mildew signs show up first, stays out of sight from the row. Here is what a drone flight genuinely documents on a hop yard, and what it does not replace.

Published on 8 September 2026, reviewed on 11 September 2026 — regulations in force as of September 2026.

Hops: a fast-growing industry concentrated in Alsace

French hops are growing at a rate few niche crops experience: according to FranceAgriMer's 2024 figures, national acreage reaches 750 ha, up 92% in just over ten years. That growth remains heavily concentrated: the Bas-Rhin département alone accounts for 478 ha in 2024, 95% of Grand Est's acreage and 63% of France's total — with Grand Est as a whole representing 67% of the national figure. Around Haguenau, the industry's historic heart, Alsatian hop yards sit alongside newer ones springing up in the Hauts-de-France region.

The rest of the growth is happening elsewhere: the historic regions now account for only 75% of French acreage, against 25% spread across the rest of mainland France since 2018 — a diversification driven by the rise of craft breweries, now more than 2,300 in France, some of them keen to source locally rather than import. Organic hops follow the same trend: 12% of harvested area in 2021, over 50 t produced, with demand from organic brewers still outstripping supply. For a grower or cooperative investing in a new hop yard, every season counts — and an aerial diagnosis quickly becomes more than a cosmetic extra.

A plant that climbs 6-10 m: the row's blind spot

A hop yard looks like no other farmed plot: the plant climbs strings run down from poles roughly 7 m tall, linked by a network of horizontal steel wires. Between April and June, the bine — the climbing stem — grows several metres, reaching 6 to 10 m within weeks, before flowering and being harvested whole, typically between 1 August and 15 September in France.

That vertical architecture has a direct consequence for health monitoring: the top of the foliage, most exposed to sun and open air, is also generally where the earliest signs of stress or disease show up first — and it is precisely the part least visible from the row, where a ground-based scout only sees the inner, lower face of a canopy curtain several metres tall. An exhaustive walking survey of a multi-hectare hop yard remains physically possible, but it never shows the whole canopy at the same instant, nor its full upper face. A drone flight, flown above the top of the poles, instead captures that upper face of the foliage in its entirety — exactly the view a ground-based scout cannot get, however much time is spent trying.

Vigour, downy mildew: what a multispectral image shows

Two threats shape hop health protection throughout the growing season: downy mildew (Pseudoperonospora humuli), particularly active during spells of frequent rain, and powdery mildew. In organic growing, only copper spraying keeps downy mildew in check, with no real cure once infection has taken hold — hence the value of detecting it as early as possible.

A Czech team led by Jana Řeřicha, with Matěj Kohútek, Věra Vandírková, Karel Krofta, František Kumhála and Jitka Kumhálová, published a study in the journal Remote Sensing in 2025 covering four consecutive seasons of multispectral drone flights over hop yards: the vegetation indices NDVI, GNDVI, NDRE, CIR and SAVI are used there as indirect indicators of vitality, health and canopy structure, to predict both yield and quality — the alpha-acid content of the cones, the parameter that weighs most heavily on a hop harvest's commercial value (see the study on Google Scholar).

On downy mildew specifically, no study has yet focused on hops using drone imagery, but the method transposes from a related perennial, trellis-trained crop: a Portuguese team led by Fernando Portela, with Joaquim J. Sousa, Cláudio Araújo-Paredes, Emanuel Peres, Raul Morais and Luís Pádua, published a multi-temporal multispectral drone survey of vineyard plots in Agronomy in 2025, half treated and half untreated, across seven flights spread over the phenological stages: the vegetation indices and morphometric parameters derived from the imagery distinguished how downy mildew progressed differently between treated and untreated plots over the season (see the study on Google Scholar). The principle — repeated flights over the season to track progression rather than a one-off diagnosis — transposes directly to hop yards: hop downy mildew (Pseudoperonospora humuli) remains a distinct species from the vine's, but follows the same wet-weather spread mechanism.

One regulatory point specific to hops is worth flagging: the 27 December 2019 order sets a 10 m no-spray buffer from the boundary of neighbouring homes for ground-based phytosanitary application on hops — a distance our guide to weed mapping and no-spray buffer zones details for every crop concerned. This constraint applies to ground-based application, not to the observation flight itself, but it still needs building into any map handed to the grower.

Method and 2026 prices

These missions are commissioned by independent growers, hop cooperatives centralising monitoring for their members, craft breweries keen to secure a local supply, and Grand Est or Hauts-de-France regional farm authorities supporting diversification into this crop. Sensor choice follows the same logic as for other perennial crops: multispectral for vigour and downy mildew monitoring, high-resolution RGB for structural inventory of the trellis (poles, wires, missing plants) — our guide to choosing between a multispectral and an RGB camera details that trade-off.

Ranges observed in France in 2026, excl. VAT:

These amounts cover the flight, index processing and map delivery; they exclude both the official phytosanitary diagnosis of a suspected outbreak (an approved laboratory or the plant health body, FREDON) and the phytosanitary application itself, distinct from the mapping described here — our guide to drone spraying and application in agriculture covers that side. For a grower, a cooperative or a partner brewery, request a quote stating the area, the goal (vigour, downy mildew monitoring, trellis inventory) and the number of passes wanted over the season.

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