21/03/2018 - 15:43

 

 

The fungus Metarhizium brunneum is capable of causing a significant mortality of eggs and young larvae of two species of pine processionary moth (Thaumetopoea pityocampa and Thaumetopoea wilkinsoni).

This is the conclusion of an international study that had the participation of CEF (Forest Research Centre, School of Agriculture, University of Lisbon). The article, co-authored by the CEF researchers Manuela Branco and Hugo Gonçalves, and also by Arlindo Lima (LEAF, ISA)  was published on the journal "Biocontrol Science and Technology".

During the investigation, bioassays were conducted to determine the susceptibility of egg masses and young larvae of two pine processionary moth species to two strains of the entomopathogenic fungus Metarhizium brunneum. Mortality of treated eggs by both strains ranged from 96% to 99% but not all of this was caused by M. brunneum since control groups also experienced egg mortality due to saprophytic fungi. Still, larvae hatched in the laboratory from eggs treated with M. brunneum were all killed by this fungus, acquiring M. brunneum conidia, whereas larval mortality was 0% in the control groups. Young larvae of both pine processionary moth species were also highly susceptible to two two strains of that fungus with larval mortality ranging between 94% and 100%, 8 days post-inoculation, with the vast majority of larvae being killed within the first 2–4 days.

Results were consistent across the two pine processionary moth species, showing that the pathogenicity of M. brunneum to both eggs and young larvae might be promising for biological control of these insect pests. The study also showed that non-target parasitoids of pine processionary moth eggs were also susceptible to M. brunneum. Further work is required to understand and reduce the M. brunneum effect on non-target insects.

This international study was attended by three Portuguese researchers from ISA - School of Agriculture, University of Lisbon

Article link: https://doi.org/10.1080/09583157.2018.1447084