Ten of Germany’s 16 states are battling a population explosion of the oak procession caterpillar, which is covered in up to 63,000 highly toxic hairs and can cause extreme allergic reactions in humans – including painful rashes, fever and breathing problems, according to newspaper reports.
Local health authorities have recorded a “year-on-year growing trend“ of the dangerous insects in the forests of Berlin and Brandenburg in particular, the Berliner Morgenpost reported on Friday. Now the battle is on to remove the nests from public spaces to protect the public.
In the third stage of larval development, oak procession caterpillars develop stinging hairs which contain a toxic protein. If touched, hooks on the hairs embed themselves deep in human skin, causing pustules and an itchy rash.
The hairs also travel on the wind and can lead to breathing problems if inhaled, asthma attacks, fainting and a high fever.
While infested areas in forests are usually simply roped off, nests in cities can only be removed by specially trained pest controllers who vacuum or burn them. The caterpillars build nests very fast and infestations must be caught early to avoid complicated and costly removals, wrote the paper.
If the vermin have established themselves, the surrounding area must be thoroughly cleaned of hairs, which can stick around long after nests have been removed. The process can cost up to €1,000 per nest.
“The webs appear overnight,” said Julia Milhahn, 36, who lives on the edge of the Grünewald forest in Berlin. Each year, more nests appear in her back garden, but the number leapt from four in 2007 to 21 in 2011.
“[Removing them] costs €400 to €500 and only helps for this season,” Milhahn told the paper.
Apart from Brandenburg, the states of Bavaria, Baden-Württemberg, Hesse, Rhineland-Palatinate, North Rhine-Westphalia, Lower Saxony, Saxony-Anhalt and Mecklenburg Western-Pomerania are said to be particularly affected by the poisonous pests.
At the start of the caterpillar season in May the Julius Kühn Institute (JKI), a federal plant research centre, issued a nationwide warning. Anyone noticing the white webs or suffering from symptoms should alert authorities or seek medical advice.