Microbial pest control in forestry and urban greenery.

Corythucha ciliata, a dangerous pest of plane trees in urban areas; Leptoglossus occidentalis, an alien invasive species originating in North America and attacking conifers; Xanthogaleruca luteola, a pest of elms trees in urban parks; Rhynchophorus ferrugineus, the insect killing palm trees in the Mediterranean area; and Thaumetopoea pityocampa, a highly destructive pines trees pest, are five examples of pests threatening forests and urban green areas. In addition, the chemical pesticides used against those pests can result in ineffective control while presenting a risk to individuals as well as to the environment. Therefore, in this study the potential use of entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPF) as biological control agents was evaluated in laboratory and field conditions. Native strains of EPNs (Steinernema feltiae, S. carpocapsae and Heterorhabditis bacteriophora) and EPF (Beauveria bassiana and Metarhizium anisopliae) were used to control larval (T. pityocampa, X. luteola, R. ferrugineus and L. occidentalis) and adult stages (C. ciliata, L. occidentalis, R. ferrugineus and X. luteola). All the entomopathogens demonstrated the ability to control these pests. Beauveria bassiana and Steinernema feltiae caused significantly greater mortality rate in the adults and larvae than M. anisopliae, S. carpocapsae and H. bacteriophora. The results showed that these entomopathogens are potentially effective biological control agents against forestry and urban greenery pests and a valid alternative to chemical control.