War on caterpillars begins, Marbella

Marbella Council has initiated its annual campaign on urban trees to prevent the spread of the pine processionary caterpillar (Thaumetopea pityocampa), one of the most common and harmful pests in green areas, which poses significant health risks, particularly to children and pets. 

The treatments are being carried out at this time to allow the product to distribute through the trees’ vascular systems and reach the pine needles, so as to ensure maximum effectiveness when the first larvae hatch and begin feeding.

The insect’s life cycle begins in summer when butterflies lay eggs on pine needles. After about four weeks, the caterpillars hatch and feed through autumn and winter while forming distinctive silk nests in sunlit branches. Between February and March, they descend in processions to burrow and complete their metamorphosis. Egg hatching is staggered and influenced by climatic factors, such as high temperatures, which can accelerate their emergence.

Pine processionary caterpillars (Thaumetopoea pityocampa) are dangerous due to their urticating hairs, which contain an irritating chemical called ‘thaumetopoein’, which can cause severe skin rashes, eye irritation, and potentially allergic reactions in humans and other mammals upon contact. Pets are at particular risk. The caterpillars are recognisable due to their nose-to-tail processions and tent-like nests in pine trees. Their protective hairs, which fifth-stage larvae can eject as harpoon-like structures when threatened, penetrate exposed skin and release an irritant protein. Their destructive feeding on pines and cedars in Central Asia, North Africa, and Southern Europe, combined with their ability to thrive in warmer climates, worsens their impact, making them a significant ecological and health concern.