Pine Processionary

The pine processionary, Thaumetopoea pytiocampa, a major pest in the golf courses in pine forests, particularly in southern and central Spain. It is a caterpillar, that is to say, the larval stage of this lepidopteran (butterfly) with an annual life cycle. The adults, the butterflies, lay their eggs in late summer on the tips of pine and cedar branches, forming nests or clusters. A month later, the caterpillars hatch and emerge from the nests during the day to feed on the young shoots of pine needles, until, in spring, they descend to the ground to burrow; they move to warmer areas in search of an optimum temperature of 20°C, marching in single file with the female leading the procession, hence its name, the processionary caterpillar.

The pine species most susceptible to attack are: Pinus nigra, Pinus canariensis, Pinus sylvestris, Pinus pinaster, Pinus halapensis and Pinus pinea. 

Fighting methods :

• Traps with female sex pheromones, so that males are attracted and trapped, preventing female fertilisation. Useful method when infestation is low. To be carried out when the pupae hatch and the adults emerge, i.e. in summer.
• Manual removal of bags.
• Physical barriers. At a certain height in the pine tree, a cone is placed around the trunk, and when the caterpillars descend, they are trapped and die of starvation.
• Conventional chemical insecticides, pyrethroids such as alphacypermethrin, deltamethrin... application should be in winter, when the larvae are young.
• Biological methods, promotion of insectivorous birds such as coal tits and blue tits; use of Bacillus thuringiensis (bacteria) which produces an endotoxin, applied in autumn. After application to the pine trees, it is ingested by the caterpillars and kills them.