Development of Environment-Friendly Strategies in the Management of Processionary Moths

Abstract

Although the aim of this chapter is to address all processionary moth species, the information provided is almost exclusively based on the pine processionary moth, Thaumetopoea pityocampa. References to other species are provided whenever available. Attempt to control the pine processionary moth quickly developed in Europe since the end of the nineteenth century because of both the risks related to the urticating larvae and the defoliation threatening pine forests and plantations. Indeed, the massive afforestation campaigns replanting Austrian black pines, Pinus nigra, on deforested mountains of southern Europe had led to large moth outbreaks in this region. Later, in the middle of the twentieth century, North Africa faced similar outbreaks following the plantation of pure stands of Aleppo pines to serve as a barrier to desertification. In these young plantations, control methods generally consisted in a manual removal of the larval tents. Forest General Inspector Julien Calas mentioned such removal operations carried out during winters 1894–1896 on 1,000 ha of pine forests in the French department of the Pyrenees-Orientales during which 1,275,000 winter tents of pine processionary moth were destroyed for a budget of approximately 5,000 French Francs of that period (Calas 1897, 1900). Then, spraying of large forest surfaces with DDT was commonly used until the late 1950s in Spain and France (Grison et al. 1959), being still considered by forest managers as an efficient, easy to implement and cheap control method (Dafauce 1970). However, large concerns quickly arose about the environmental impact of this pesticide as well as about the development of insect resistance. Therefore, research turned towards the possibilities of using entomopathogenic bacteria and viruses to control T. pityocampa, and the first studies started during the same period in France.