It's oak processionary panic season!

There are way too many cases of conservation projects failing in spectacular manners that environmentalists still fail to call out for various reasons. This one however, is so "in your face" about it that it's becoming more and more obvious that most of the public's rather sudden interest matters were pure fads that will get abandoned and even its own respective history obfuscated the moment it stops being the latest political trend.

The oak processionary is a moth species assumed to be profiting off climate change – or so it seems, since it was accidentally introduced to the UK in 2005 via commercial trade of oaks. While the imagines are unremarkable in virtually every sense, its caterpillars are feared among mayors and tourists for causing pseudo-allergic reactions. The term "pseudoallergic" is being omitted in public discourse due to defeating the point of the recurring mass hysteria regarding bugs that CAN be harmful to humans if they're dumb enough to chew on them (such as kids picking everything they see lying on grounds, even a Meloe proscarabaeus, up to chew and suck on them because their parents failed to teach them that stuffing stuff you find on the ground of your local playground is gross and "no-no"). Pseudoallergies resemble a typical allergic reaction in terms of visible symptoms in the absence of Immunoglobulin E (IgE), the mediator during allergic reactions. Mast cells instead are being activated directly and is often considered to occur after taking certain drugs, such as aspirin and opioids [1].

Pseudoallergies are poorly understood and virtually not understood at all outside of drug studies, hence most claims asserting the (pseudo-)allergic responses to the tiny – not long! – hairs of oak processionary caterpillars are dubious at best. Even its Wikipedia article's "Public health problem" section is almost completely lacking citations proving that credible science has come to the conclusion that this species really is such a big public health concern [2].

But now we've reached a state where such a manufactured mass hysteria is resulting in large conservation areas being treated with biocides containing Bacillus thuringiensis with the approval of environmental organizations. The UNESCO nature reserve Drömling in Saxony-Anhalt is set to see more than 800 hectares of its area being treated with this bacterium via helicopter, citing an analysis that determined that this drastic measure is necessary in spite of conservation laws due to Drömling "being among the largest and most affected regions in Germany". This decision was approved by unnamed environmental organizations [3]. Browsing the website of Central Germany's public broadcaster doesn't yield any results that would indicate some sort of neutrality, repeatedly highlighting the "dangers" of the caterpillars near playgrounds and parks. The bacterium's German Wikipedia article blatantly omits its negative effects on protected species and instead promote its application in gardens against harmless ermine moths, whereas the English article at least dedicates three lousy sentences to the effects on non-targeted species where negative consequences are being denied and a "Controversies" sub-section where, once again, negative impacts on monarch butterflies are being denied again [4].

Things look much weirder when studying the nature reserve's official homepage. Unlike the MDR, the nature reserve actually states that the panic is indeed a panic and that any measure protecting public health has to be as conservative as possible to avoid environmental degradation. Unfortunately, this page was last updated in 2021 and includes a link to a project of the Anhalt University of Applied Sciences that leads to a 404 page. According to the nature reserve, this study was supposed to assess possible pest control methods, with the project set to conclude after two years [5]. No results were ever published, despite the nature reserve's promises of updating its own page when results become available. The page provided by the university has only been crawled five times by the Internet Archive's Wayback Machine since its inception, revealing that it already vanished between 2022 and 2023. Only three captures, all originally crawled in 2021, provide any information, whereas the only 2023 capture leads to a 301 error. The newest caption, dating back to 2024, leads to the universities' not found page, meaning the project simply disappeared without ever being completed [6]. No studies have been conducted since 2020 and the concept required to meet the criteria post-UNESCO recognition is dangerously close to missing its deadline, as it's already been three years since the area had been awarded its UNESCO title. Missing this deadline, on the other hand, never has been punished by the UNESCO, in fact Drömling won't see any consequences until 2033 when the UNESCO's planned re-evaluation is set to occur (unless they're greedy enough and decide to build a bridge across the area like Dresden several years ago).

It goes without saying that the entire website obviously caters to tourists seeking "experiences". Even the news seem to get autodeleted after just a year, with no official archive being maintained. The list of animals living in this area is restricted to a handful of birds and just four mammals – no bats, no bugs, nada. Just "charismatic species". Plants are excluded entirely and the "living space" page merely links of a PDF from 2007 (!) discussing management and development plans. It's a tourist trap, nothing else.

This very focus on selling "experiences" and "feel-good politics" actively contributes to the decline of species across flora and fauna but NGO's were reluctant to (openly) embrace it until now. Now they support it and merely just tell those writing those press releases to omit their names. (Given how the nature reserve switched its tone over the years, it's unlikely that NGO's weren't consulted at all and that its support is a lie made up by said nature reserve and/or some local mayors.)

So far any measures to combat the spread of the oak processionary merely accelerated its expansion, whereas other, non-targeted species continue to decline. Since there is a persistent reluctance to study the impact on European species, it's impossible to determine the true impact and whether the decline is mere correlative (one link among many) or causal (BT-toxins directly killing vulnerable species). Despite this, the effects of other pesticides on non-targeted species already are well-known, yet even those remain in use and lobbyism prevented the ban on glyophosate for another ~ten years, so it's fair to assume that this biocide is not safer than conventional pesticides – it's a biocide, after all.

And to the suburban people whining about itchy skin and mild breathing problems only after spotting a bunch of oak processionaries: Go pop some antihistamines like the rest of us with "true" allergies that often do not respond to the "hyposensibility" treatments if you really must visit the caterpillar-dominated places during its respective peaks. They've improved a lot since the 70's.

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[1]

"Pseudoallergy" (Encyclopedia of Immunotoxicology)

[2]

Oak processionary (English Wikipedia)

[3]

[GER] "Altmarkkreis Salzwedel: Heli-Flüge gegen Eichenprozessionsspinner beginnen" (MDR.de, 14 May, 2026)

[4]

Switch between the English and German Wikipedia for comparison and feel free to use any translation software if you don't speak German.

Bacillus thuringiensis (English Wikipedia)

[5]

[GER] Eichenprozessionsspinner im Drömling (Biosphärenreservat Drömling)

[6]

Wayback Machine Search