Biological control of the new, invasive Sirex woodwasp


2007 to 2018


Sirex woodwasp, an aggressive species with wood boring larvae, is known to kill pines in the southern hemisphere where this European woodwasp and pines have both been introduced. It has been introduced to North America and was first collected in 2004 in New York state. We are investigating the potential use of a biological control agent, a sterilizing parasitic nematode, that has proven very effective in the southern hemisphere, with particular emphasis on investigating the potential for non-target effects. We are also investigating the associations between the white rot fungal symbiont of Sirex and native North American Sirex species.


The European woodwasp Sirex noctilio was first found in North America in 2004. This woodwasp has been a major cause of tree mortality in pine plantations in the southern hemisphere over the past century. We are investigating the potential for introducing a nematode that parasitizes this species; this nematode has proven highly effective in controlling S. noctilio at some locations in the southern hemisphere. All Sirex are obligately associated with white rot fungal symbionts. We have been studying the fungal strains and species associated with Sirex noctilio and with native Sirex to understand the specificity of these associations.


Our laboratory has been identifying the natural enemies that are attacking S. noctilio in New York. This woodwasp must carry with it a pine-pathogenic fungus, and we have identified the strains of this fungus that were introduced with S. noctilio. Although S. noctilio has been introduced to many places in the southern hemisphere, this is the first time that it has been introduced to a location where pines and other species of Sirex are native. The nematode that parasitizes Sirex noctilio and has been used for biological control also specifically requires the symbiotic fungus carried by Sirex.
The symbiotic fungi that are carried by native Sirex species are poorly known, and we have been identifying these fungi to look for any potential shared use of symbiotic fungi between S. noctilio and the native Sirex. We have found that the fungus used by S. noctilio is also occasionally associated with native North American Sirex, so there is the possibility that the biological control nematode will be in contact with native Sirex. We are investigating the extent that the nematodes parasitize the native Sirex as well as S. noctilio in New York. Because the parasitic nematode that we have been investigating requires the fungus for food, we have also been investigating interactions between the biological control nematode, nematodes associated with native Sirex and species and strains of the white rot fungi associated with Sirex in North America.
We present ongoing results yearly at conferences focusing on gypsy moth and invasive species that land managers attend.


The invasive woodwasp pest, Sirex noctilio, has great potential to kill pines, especially in pine plantations. We are investigating a means for control that would be environmentally friendly and could provide long-term control once established. At the same time we are learning more about native North American woodwasps and how they will be impacted both by this more aggressive invasive as well as by control measures that might be used against the invasive woodwasp.

Submitted by: 

  • Hajek, Ann E

Researchers involved: 

  • Hajek, Ann E
  • Williams, David W
  • Nielsen, Charlotte
  • Morris, E. Erin
  • Caetano, Isis A. Lima
  • Castrillo, Louela
  • Bittner, Tonya
  • Csoka, Gyorgy
  • Pajares, Juan

Organizations involved: 

  • USDA Animal and Plant Health Inspection Service

International focus: 

  • United States of America
  • Australia
  • Canada
  • New Zealand
  • South Africa

United States focus: 

  • New York