The Caterpillar from Hell 🍃🐛 with Kesser and Steen, Nature and Innovation class

The Caterpillar from Hell - Odense, Denmark - The Larva from Hell: Battling the Oak Processionary Moth. These days the invasive spread of oak processionary caterpillars in Denmark, specifically highlighting a severe infestation in Odense linked to imported trees. These pests are notorious for their toxic hairs, which pose significant health risks to humans and animals while threatening the health of local oak forests. Although biological solutions like Bt-toxin exist, current Danish regulations and bureaucracy hinder efficient large-scale treatment, forcing authorities to rely on slower manual removal methods. Amidst this frustration, two young innovators named Kesser and Steen have proposed using autonomous drones and specialized biological units to target the larvae more effectively. Ultimately, the sources advocate for urgent government intervention and the modernization of environmental laws to prioritize public health over administrative red tape. Oak processionary moth (Thaumetopoea processionea) When we talk about the "larva from hell" in Denmark, we mean the oak processionary moth (Thaumetopoea processionea). Although the name is very similar to the common (and harmless) oak moth, the processionary moth is notorious for its extremely toxic micro-stinging hairs. The larvae have a very simple and one-sided menu: Fresh shoots and leaves from oak trees: The larvae feed almost exclusively on leaves from all types of oak (Quercus). They hatch in early spring, just when the oak trees are starting to sprout, so they can munch on the very young, fresh leaves. Plan B (emergency solution): If a large group of larvae completely eats the oak tree naked (defoliation), and there is no more food left, they may wander in their familiar rows (processions) to other trees. Here, for lack of better food, they can eat leaves from hornbeam, beech or birch to survive, but this is purely a survival instinct. The oak tree is their absolute favorite food and base. The adult moths, which the larvae transform into during the height of summer, do not eat at all – they only live to mate, lay new eggs in the oak trees and die shortly afterwards. How did the problem end up in Odense? -“ experts point out that the oak processionary moth came to Denmark via the import of oak trees from abroad (probably from the Netherlands, NL). When importing half-grown oak trees to plant avenues quickly, there may be overwintering egg masses or old nests hidden in the bark and branches. When the trees were planted in the ground in southeastern Odense (around Tornbjerg, Lindved and the Kohave area), the larvae were given ideal conditions to hatch, spread and establish a permanent population. It is precisely this case that has made experts sound the alarm. Among other things, researchers from the University of Copenhagen have proposed that much stricter controls and requirements for "plant passports" be introduced for imported oak trees, so that plant inspectors can check the trees thoroughly at the border before they are planted in Danish cities. The situation in Odense has proven to be incredibly difficult to overcome, because the larvae have spread to over a thousand trees in the area, and their microscopic fire hairs cause major problems for residents, cyclists and pets alike. Kesser and Steen are running their very own bio-chemical lab in the backyard. When two 11-year-old boys throw themselves into the knowledge of toxin control of cabbage worms and mosquitoes, you are balancing on a pinch of genius. They actually can do it in theory, and the method with biological toxin is already being used in some places – although typically from the ground with large sprayers rather than drones. A bacterial toxin called Bacillus thuringiensis (Bt toxin). It is an organic and biological agent that only affects butterfly and moth larvae when they eat the leaves, without harming birds or people. When drones are not just used everywhere in Odense, it is primarily due to legal reasons: Legislation on aerial spraying: In Denmark and the rest of the EU, it is basically illegal to spray with agents from the air (which includes drones) in densely populated urban areas due to the risk of wind blowing the poison into people's gardens or hits random passersby. Hits other species: Although Bt toxin is biological, it does not distinguish between the poisonous oak processionary moth and other harmless or endangered Danish butterfly larvae that live in the few oak trees at the same time. Timing: The poison only works in a very short window in the spring, just when the larvae have hatched and are eating the most. If you miss those weeks, the larvae have developed their fire hairs. Instead of drones, Odense has primarily used methods such as manually vacuuming the nests or burning them with gas burners to control the spread. #gardening #caterpillar #kesserogsteenpåtur #Thaumetopoea #egeprocessionsspinder Copyright 2026 - Flamme Rouge 🚩 Nature