Investigating the Sirex noctilio - parasitoid complex in New York State

Sirex noctilio, an invasive wood-boring wasp native to Europe and Asia was detected in Fulton, New York in 2004, and is now found throughout the state. In its native range, S. noctilio is a minor pest, but in areas of introduction it has caused significant economic damage to pine plantations. A suite of parasitic wasps native to North America have been used as biocontrol agents in other areas of S. noctilio introduction, but affects of these parasitoids in the United States are relatively unknown. Our goal was to determine native parasitoids associated with S. noctilio mortality and rates of mortality associated with parasitism. Sixty three infested red and Scot's pines from 10 sites in northern and central New York were felled and transported to SUNY-ESF for rearing. Emerging insects were collected and species densities per square meter of bark were calculated. Preliminary results indicate that native parasitoids account for ca. 20% of S. noctilio mortality, with Ibalia leucospoides accounting for >60% of mortality and rhyssine parasitoids the remainder. Knowing rates of parasitism in New York will contribute to understanding the role native parasitoids may play in slowing the spread of S. noctilio to more economically valuable southern pine plantations as well as western pine forests.