The Rescue of Moselle Apollo and Steep-Slope Viticulture

At the end of 2023, we have reported for the first time on the serious threat of the Moselle Apollo by a possibly upcoming legal ban of the helicopter sprayings of pesticides in steep-slope vineyards along the Moselle valley. In continuation, in April 2025 a report has been published on the to be feared imminent extinction of the unique papilionid butterfly in the picturesque and outstanding viticultural landscape on the Moselle, with its millennia tradition, and on the absurd and war-declaration-like lawsuit filed by the Melanargia – Arbeitsgemeinschaft Rheinisch-Westfälischer Lepidopterologen (AGL) and the Deutsche Umwelthilfe (DUH) against the Aufsichts- und Dienstleistungsdirektion (ADD) of the state of Rhineland-Palatinate for a judicial ban of the helicopter sprayings in steep-slope vineyards on the Moselle, which in the meantime has according to expectation and fortunately been rejected by the administrative courts in four judgements in two instances. Thus there is now renewed hope, a perspective and a future for the steep-slope viticulture and the Moselle Apollo in the Moselle valley. A report by Dr Detlef Mader (editorially revised by weinfreaks.de).

After much back and forth, controversial pros and cons, numerous efforts and various legal issues and proceedings, the good news can now be announced: helicopter sprayings of pesticides can be continued to be carried out in steep-slope viticulture on the Moselle, and the Moselle Apollo is saved.

The Apollo Butterfly or the Red Apollo (Parnassius apollo) was formerly distributed in more than 200 regionally limited subspecies throughout Europe, with many of them, however, having already become extinct in the last 100 to 150 years. With the Moselle Apollo (Parnassius apollo vinningensis), one of the numerous subspecies lives at the Moselle.

The Moselle Apollo lives already since many centuries on the steep rocky slopes of the Moselle valley where white and yellow sedum (white and yellow stonecrop), the most important food plants of the caterpillars, and meadow knapweed and scabiosa knapweed, the most important nectar plants of the butterflies, grow in widespread and abundant distribution, and where the flight sites of the thermophilous butterfly are blessed by the sun due to the much stronger and longer insolation on the steep slopes than in the flat areas. The blossoms of the knapweeds do not only serve as refuelling stations for the butterflies to drink nectar, but function above all as meeting places of males and females of the Moselle Apollo for preparation of mating. A second colourful, majestical and marvellous big papilionid butterfly at the flight sites of the Moselle Apollo in the steep-slope vineyards is the Scarce Swallowtail (Iphiclides podalirius).

Many sections and intervals of the steep slopes are farmed and maintained by viticulture since more than 2000 years, with the active viticulture keeping the rocks and gravel fields open and thus protecting the flight sites of the Moselle Apollo from becoming overgrown by the spreading vegetation. It can be assumed that the Moselle Apollo has already flown in Roman times and is therefore established in the Moselle valley for more than two millennia. At the Calmont between Bremm and Ediger-Eller, the Moselle Apollo is at home also at one of the steepest vineyards of the world.

More than 100 to 150 years ago, the Moselle Apollo has still been widespread between Winningen and Traben-Trarbach and possibly also Bernkastel-Kues, and has also been present in parts of Eifel and Hunsrück near the Moselle valley. Since then, however, more and more habitats of this unique butterfly in the Moselle valley and all habitats in Eifel and Hunsrück have disappeared, and thus the population of the Moselle Apollo has retreated to the area between Winningen and Bremm and possibly also Pünderich in the last decades.

At the remaining active flight sites, the population sizes of the Moselle Apollo have declined dramatically in recent decades and even in recent years, and in some cases have even dropped to extremely low levels. The drastical collapses of the population size of the Moselle Apollo have been caused predominantly or even almost exclusively by extreme climatical events (above all arctical permafrost periods with two-digit frost temperatures in winter, extraordinarily abundances of late frost nights, exceptionally dry and hot summers, and outstandingly rain-rich and cool springs and summers). The decisive dramatical and catastrophical population crashs of the Moselle Apollo in 2012, in 2019 and in 2024 have mainly been caused by the arctical permafrost periods with double-digit frost temperatures in winter in 2012 and in 2021, the exceptional accumulations of late frost nights after mid of March in 2019 and in 2020, the extraordinarly cold spring (April and May) in 2021, and the outstandingly dry and hot summers in 2022 and possibly also already in 2018.

Subordinate influences on the recession of the population size of the Moselle Apollo had the loss of habitats due to overgrowth and coverage of rocks and gravel fields by the vegetation after abandonment of uneconomical steep-slope vineyards, mainly by spreading of bushes and trees in the succession leading to forestation.

The long-term balance of the population size of the Moselle Apollo which has changed permanently between an accelerated population size of approximately 1000 to 1500 specimens, an intermediate population size of approximately 750 to 1000 individuals and a retarded population size of approximately 500 to 750 specimens from 1985 until 2011, and which has tended to remain constantly within the long-term stable fluctuation range between an upper resistance line of approximately 1500 individuals and a lower support line of approximately 500 specimens from 1985 until 2011, has been seriously and decisively broken downwards for the first time in 2012 as a consequence of the arctical permafrost period with double-digit frost temperatures in 2012, when, after an accelerated population size and a spectacular mass flight in 2011, the Moselle Apollo suddenly and abruptly has crashed within just one year to a sub-residual population size of only still approximately 150 to 300 specimens in 2012.

After a temporary recovery to a retarded population size of approximately 500 to 750 specimens in 2013 and in 2014, the Moselle Apollo has continued to decline and has fallen via a severely retarded population size of approximately 300 to 500 specimens from 2015 until 2018 to a residual, relictical or even sub-extinct population size of only around 100 to 200 specimens in 2019. After another temporary slight recovery to a total of only about 150 to 300 specimens in 2020, the collapse of the Moselle Apollo has continued steadily and, via a residual, relictical or even sub-extinct population size of only about 100 to 200 specimens from 2021 until 2023, has finally reached the limit of extinction by a renewed crash to a terminal or pre-extinct population size of only about 50 to 100 specimens in 2024 and in 2025.

With the current almost subfinal population size of only around 50 to 100 specimens in the actual distribution area of the Moselle Apollo in the Moselle valley which in comparison to former times is severely reduced and considerably thinned out, the persistent and consequent farming and maintenance of the rocky slopes by steep-slope viticulture has decisive importance for the survival of the Moselle Apollo, because without continuous steep-slope viticulture, the remaining active flight sites would become overgrown by the spreading vegetation in the foreseeable future.

Since 2020, in the framework of a rescue program for the Moselle Apollo from extinction, nature conservationists are regularly and systematically keeping selected areas on the steep slopes open by cutting back and removing the vegetation in winter and in early spring. The natural distribution of the aforementioned food plants of the caterpillars and nectar plants of the butterflies of the Moselle Apollo is supplemented and expanded by planting of additional quantities from horticulture. Since 2020, every spring large numbers of caterpillars having been bred under controlled conditions in the laboratory are released at the remaining flight sites and at the already extinct flight sites in the Moselle valley, as well as in selected side valleys of the Moselle valley where the Moselle Apollo has either never occurred or has last occurred 100 to 150 years ago.

The combination of maintenance of the natural habitats of the Moselle Apollo by management and care of the rocks and gravel fields by steep-slope viticulture on the one hand and the aforementioned rescue measures by nature conservation on the other hand secure the further existence of the population of the Moselle Apollo in the pittoresque steep-slope vineyard landscape with millenia-old history in the Moselle valley in the future independent of further extreme climatical events and prevent that the Moselle Apollo suffers the fate of the numerous other subspecies of the Apollo Butterfly or Red Apollo in Europe which have already become extinct.

Some nature conservationists question my interpretation that the population collapses of the Moselle Apollo have been caused exclusively by the aforementioned extreme climatical events and fear that the helicopter sprayings of pesticides in steep-slope vineyards since the early 1970s may have had a negative impact on the population size of the Moselle Apollo. However, I cannot see any connection between the helicopter sprayings and the aforementioned population crashs, because from the start of the helicopter sprayings in the early 1970s until 2011, the Moselle Apollo has permanently fluctuated alternatingly upwards and downwards within the aforementioned stable equilibrium of population size and has only fallen seriously and decisively below the previous support line for the first time more than 40 years after the start of the helicopter sprayings.

Furthermore, the population collapses of the Moselle Apollo since 2012 have not only occurred at flight sites being farmed and maintained by steep-slope viticulture, but have also happened at flight sites being located outside of the vertical and lateral extension of steep-slope viticulture and thus outside of the routes of the helicopter sprayings. Steep-slope viticulture on the Moselle is already now only marginally profitable and would be completely unprofitable without the annual helicopter sprayings, so that a legal ban of the helicopter sprayings would inevitably lead to the abandonment of steep-slope viticulture, which in turn would mean that most of the remaining flight sites of the Moselle Apollo would become overgrown by the spreading vegetation in the foreseeable future. Because very numerous tourists visit the Moselle valley only for the excellent steep-slope wines and/or only for the unique Moselle Apollo, a legal ban of the helicopter sprayings would affect in considerable extension and partially even with endangering of the existence not only the steep-slope viticulture, but also the tourism in the Moselle valley.

A further powerful evidence that the helicopter sprayings of pesticides have no negative impact on the population size of the Moselle Apollo is the synchrony of population collapses since 2012 of both the Moselle Apollo (Parnassius apollo vinningensis) in the Moselle valley in an area with steep-slope viticulture and helicopter sprayings, as well as of the Altmühl Apollo (Parnassius apollo lithographicus) in the Altmühl valley in the vicinity of Eichstätt and Solnhofen, the Blau-Apollo (Parnassius apollo thiemo) in the Blau valley near Gerhausen between Blaubeuren and Blaustein and the Franconian Apollo (Parnassius apollo melliculus and Parnassius apollo franconicus) in the Kleinziegenfeld valley (Weismain valley) south of the Main valley between Lichtenfels and Kulmbach in areas without viticulture and helicopter sprayings. The synchrony of the population declines since 2012 of the Moselle Apollo on the one hand and the Altmühl Apollo, the Blau-Apollo and the Franconian Apollo on the other hand, over a distance of more than 500 kilometres from the Moselle valley, rules out local and small-scale regional causes and proves that exclusively large-scale regional and supra-regional extreme events have been the triggers of the population collapses, with the extreme climatical events described above being of primary importance.

The loss of many of the formerly numerous flight sites of the Moselle Apollo in the Moselle valley and in parts of Eifel and Hunsrück near the Moselle valley has begun already 100 to 150 years ago, and has thus already started in the pre-industrial and early industrial period when the secondary-anthropogenical acceleration of the primarily-naturally-induced current progressive climatical change had not yet begun or had only just begun, and in particular has begun well before the start of the helicopter sprayings of pesticides in steep-slope viticulture. The first former flight sites of the Moselle Apollo have even vanished around 100 years before the start of the helicopter sprayings

With the disappearance of more and more flight sites, the Moselle Apollo is repeating exactly the extinction scenario that has already led to the extinction of many other regional Apollo butterflies in central Middle Europe during the past 100 to 150 years and even still in the recent decades, so that the imminent extinction of the currently remaining natural populations of the Moselle Apollo is not a regionally limited fate. The Moselle Apollo is not the first regional Apollo butterfly in central Middle Europe which has been or is affected by extinction in the past 100 to 150 years, and is also not the last regional Apollo butterfly which will be affected by extinction in the next 100 to 150 years. Out of the many regional Apollo butterflies that have already become extinct, various species have also vanished in flight provinces without steep-slope viticulture and helicopter sprayings. Similarly, numerous flight sites of the Moselle Apollo have also disappeared at locations without steep-slope viticulture and helicopter sprayings.

In contrast to the Moselle Apollo, the other regional Apollo butterflies in central Middle Europe that have already become extinct have not been artificially supported by the annual release of large numbers of caterpillars having been bred under controlled conditions in the laboratory at their flight sites, nor have they been supported by planting of additional quantities of the most important food plants of the caterpillars and the most important nectar plants of the butterflies from horticulture, nor have they been assisted by cutting back and removing of the vegetation at the flight sites in winter and in early spring. Instead, the other regional Apollo butterflies have been left to their fate of disappearance from their habitats without active nature conservation measures. Thanks to the aforementioned rescue measures from extinction, the Moselle Apollo enjoys an exclusive privilege among the regional Apollo butterflies in central Middle Europe, ensuring its survival in the unique steep-slope viticultural province with millennia-long tradition in the Moselle valley.

The Moselle Apollo in the since Roman times and thus more than 2000 years operated steep-slope viticultural province in the Moselle valley is therefore a preferred subspecies of the Apollo Butterfly or Red Apollo throughout Europe which in case of consequent continuation of the maintenance of the natural habitats of the Moselle Apollo by steep-slope viticulture on the one hand and the aforementioned rescue measures by nature conservation on the other hand will fly also in the next two millenia at the steep slopes of the Moselle valley, when many of the other actually still remained subspecies of the Apollo Butterfly or Red Apollo will already have become extinct.

As a consequence of their apprehensions of a negative impact on the population size of the Moselle Apollo, the Melanargia – Arbeitsgemeinschaft Rheinisch-Westfälischer Lepidopterologen (AGL) and the Deutsche Umwelthilfe (DUH), after unsuccessful and failed extrajudicial negotiations with the defendants, the co-defendants and the viticulturists from their point of view, have filed two lawsuits (main case and urgent application) against the Aufsichts- und Dienstleistungsdirektion (ADD) of the state of Rhineland-Palatinate regarding the helicopter sprayings having been approved by the supervisory authority and having been carried out in 2024 and in 2025, but have lost completely in three first-instance judgements and one second-instance judgement up to date, and have to bear the entire costs of the legal proceedings. The Administrative Court (Verwaltungsgericht) of Koblenz has rejected the main case against the helicopter sprayings in 2024 (4 K 1355/24.KO and 4 K 619/25.KO) by its judgements of 16 October 2025. The Administrative Court of Koblenz has rejected the urgent application against the helicopter sprayings in 2025 (4 L 447/25.KO) by its judgement of 26 May 2025. The Superior Administrative Court (Oberverwaltungsgericht) of Rhineland-Palatinate has rejected the appeal against the judgement of the Administrative Court of Koblenz in the urgent application against the helicopter sprayings in 2025 (4 L 447/25.KO) by its decision of 18 August 2025 (1 B 10652/25.OVG), and has closed the case by having excluded further revision.

More than a year ago, immediately after the main case has been filed, I have expressed and justified my opinion in my aggressive and tough statement for the defence of the claim of 28 January 2025 that the lawsuit has no prospect of success, and I have repeatedly (especially after the judgements in the urgent application against the plaintiffs) recommended the viticulturists and their representatives to now view the matter quite calmly, relaxedly and without stress, because I do no longer expect any contrary decisions by the administrative courts. I am very pleased that it has now finally turned out exactly in the way which I have already predicted since the beginning.

On the basis of the aforementioned four judgements of the administrative courts against the plaintiffs, the appeals of the plaintiffs against the two judgements of 16 October 2025 pending at the Superior Administrative Court of Rhineland-Palatinate (1 A 11707/25.OVG and 1 A 11713/25.OVG) and further urgent applications which have to be expected to be filed by the plaintiffs against the helicopter sprayings in 2026 and subsequent years are completely hopeless and are doomed to failure from the outset, because it can be assumed that both the Administrative Court of Koblenz and the Superior Administrative Court of Rhineland-Palatinate in their decisions in the future will not deviate from their very comprehensive, very conclusive and very understandable justifications in their previous judgements. As a consequence of the now complete futility of further lawsuits and appeals following a defeat series of four rejections of claims by the administrative courts, the AGL has resigned and will no longer actively participate as a plaintiff in the further course of the legal dispute, but will only passively support the DUH, which is now the sole plaintiff, by professional advice and support.

I have subsequently appealed to the DUH as the now sole plaintiff and to their legal representation to follow the good example, the benchmark and the reasoning of the AGL and to withdraw the still pending claims and appeals, to waive further claims and appeals, and thus to terminate the totally hopeless legal dispute. I sincerely hope that the DUH and their legal representation will seriously check and consider my recommendation.

With the waive of further active participation as plaintiff in the lawsuit, the AGL has now created a solid basis for further extrajudicial meetings and negotiations with the aim of comprehensive explanation and clarification of the defendants, the co-defendants and the viticulturists on the effectivity and the environmental compatibility of the spraying chemicals which have been approved for application by the supervisory authority, and to convince them to resign to use the particularly dangerous and especially harmful substances having been criticized by AGL and DUH in the helicopter sprayings. The defendants, the co-defendants and the viticulturists have signalized that it is also in their interest to no longer apply particularly dangerous and especially harmful chemicals in the helicopter sprayings, and thus the AGL has now with its retreat from the active participation as plaintiff in the lawsuit created a promising basis for further extrajudicial meetings and negotiations in relaxed and partnership-like atmosphere with cooperation instead of confrontation.

On the basis of the aforementioned four judgements, the helicopter sprayings can further be approved by the supervisory authority without hesitation in the same extension and under the same obligations as up to now. The steep-slope viticulture on the Moselle can thus be continued as before and is saved. With the continued cultivation of the steep-slope vineyards along the flight sites of the Moselle Apollo, the remaining natural populations of the Moselle Apollo are saved through the preservation of their habitats, provided that no further extreme climatical events have no more serious negative impacts on the remaining natural populations of the Moselle Apollo. Under the requirement that large numbers of caterpillars having been bred under controlled conditions in the laboratory are continued to be released annually at the flight sites, the population of the Moselle Apollo can be stabilized through the regular and systematical artificial support and is thus saved even in the case of further extreme climatical events. The steep-slope viticulture on the Moselle and the Moselle Apollo have thus totally won the legal battle against the helicopter sprayings and can celebrate themselves as resounding victors. I have therefore recommended the viticulturists and their representatives to enjoy this success which secures their livelihoods and paves the way for the future with fine wines from their cellars.

• Dr Detlef Mader is a self-employed and independent biologist, geologist and climatologist. Since the beginning of his geological M. Sc. Thesis in the Buntsandstein (Lower Triassic) in the Eifel and in the Moselle valley 50 years ago, he has published 22 scientific books and numerous articles in scientific journals covering a wide range of biological, geological and climatological topics. Dr Detlef Mader has been born in 1954, is researching the Moselle Apollo in the Moselle valley since 2010, and is scientifically a Mosellian since half a century.

Quellenverzeichnis

• Mader, D. (2020). Apokalypse des Mosel-Apollo – Aussterben oder Überleben? Mader, Walldorf. ISBN 978-3-9815850-3-2.
  Google Drive
• Mader, D. (2021). Quo Vadis, Mosel-Apollo? Mader, Walldorf. ISBN 978-3-9815850-6-3.
  Google Drive
• Mader, D. (2022). Prolongation der Apokalypse des Mosel-Apollo am Limit der Extinktion: Stagnation, Comeback oder Requiem? Mader, Walldorf. ISBN 978-3-9815850-7-0.
  Google Drive
• Mader, D. (2026). Historie der Entwicklung der Populationsstärke des Mosel-Apollo von 1895 bis 2025. In Vorbereitung zur Veröffentlichung. Mader, Walldorf. ISBN 978-3-9815850-8-7.
  Google Drive