Toxic caterpillar on the march in Spain after mild winter leads to explosion in numbers being born early

The pine processionary caterpillar poses a threat to small children and animals, especially if the poisonous proteins it carries are ingested

The inch-long caterpillar is a common sight but could be poisonous if it is ingested

What lurks at the bottom of the garden? Across Spain, there are increasing fears that it could be the toxic pine processionary caterpillar, which is hatching earlier than usual this year because of the unusually mild weather.

Experts have warned that the caterpillar, which carries poisonous proteins in the barbs on its back, could be a particular risk to small children and animals, especially if the proteins are ingested.

The inch-long caterpillar is a common enough sight in Spain, especially in pine forests from which they get their name. The mild winter, following Spain’s hottest-ever recorded summer last year, has led to an explosion in the number being born early.

Contact with the pine processionary caterpillar, or Thaumetopoea pityocampa, causes skin irritations. Pet dogs and cats are at particular risk as they tend to lick the burns on their paws that are caused by contact with the caterpillar.

“After a winter that has been much milder and drier than normal, the population of the processionary caterpillar has flourished and brought forward their arrival,” Milagros Fernández de Lezeta, director of Anecpla, Spain’s pest-control association, told The Local news website.

“They pose a major risk to children, adults and pets causing dermatitis, eye damage and severe allergic reaction.”