Trapping Techniques for Siricids and their Parasitoids (Hymenoptera: Siricidae and Ibaliidae) in the Southeastern United States

Abstract

The recent introduction of Sirex noctilio F. (Hymenoptera: Siricidae) into North America has raised interest in native siricids and their parasitoids to better understand the potential impact of S. noctilio. In the southeastern United States, we assessed various techniques to capture native siricids and their parasitoids using traps, lures, and trap trees. During 2009–2011, in total, 2,434 wasps were caught including Eriotremex formosanus (Matsumura), Sirex nigricornis (F.), Tremex columba (L.), and Urocerus cressoni (Norton) (Siricidae), and Ibalia leucospoides ensiger Norton (Hymenoptera: Ibaliidae). Traps and trap trees, respectively, captured 14 and 86% of total siricids and hymenopteran parasitoids. Majority of siricids (76%) were caught in Louisiana, where 486 I. l. ensiger (28% parasitism rate) were also reared from trap trees. The Sirex lure alone and Sirex lure with ethanol captured two to five times greater numbers of siricids than unbaited traps. Trap types had no effect on catches of siricids. Fewer siricids were caught in traps baited with ethanol alone than in those baited with other lures in Georgia. We caught three to four times greater numbers of S. nigricornis in traps with fresh pine billets (with foliage) as a lure than traps baited with Sirex lure in Louisiana. More S. nigricornis and I. l. ensiger emerged from cut and felled trap trees created in early rather than late November; these trees also had 14 times greater emergence than those treated with Dicamba. Our results indicate that use of host material and timing may be important for monitoring populations and communities of siricids and their parasitoid species in southern pine forests.

Type of Intercept Trap Not Important for Capturing Female <I>Sirex noctilio</I> and <I>S. nigricornis</I> (Hymenoptera: Siricidae) in North America

“…Other studies reported similar Þndings. In Louisiana, Barnes et al (2014) also found no differences between panel and multiple-funnel traps in the number of S. nigricornis caught. McIntosh et al (2001) found no difference among several trap types, including multiplefunnel traps, for capturing Siricidae in western Canada.…”

“…Bioassays conducted in controlled environments to test putative attractants or trap types are one way to circumvent this problem. Another is to conduct Þeld tests of trap and lure combinations with a closely related, but more common species, as we and others (Coyle et Barnes et al 2014) suggest that these locations are ideal for such studies. However, it is unknown whether S. nigricornis populations are generally greater in this region than further north, or locations chosen for trap placement were more attractive to wasps (i.e., near a lumber mill in Louisiana vs. an unthinned P. sylvestris plantation in Ontario).…”

“…Although not examined in our study, lure type has been investigated, and shown to be important for S. nigricornis. Intercept traps baited with the commercially available Sirex lure caught more S. nigricornis than unbaited traps, and those baited with pine foliage and log billets caught even more (Barnes et al 2014). Johnson et al (2013) found that intercept traps baited with semiochemicals (e.g., Sirex lure ϩ ipsenol ϩ ipsdienol) generally caught more S. nigricornis than trap trees.…”

“…Studies have tested and improved lures for woodwasps (Siricidae) , Cooperband et al 2012, Coyle et al 2012, Johnson et al 2013, Barnes et al 2014), but information on effective trap type is limited to studies of related species (McIntosh et al 2001, Costello et al 2008, Barnes et al 2014. This is probably not because efforts have been lacking, but more likely because of difÞculty in comparing low S. noctilio catch among different traps.…”

“…This is probably not because efforts have been lacking, but more likely because of difÞculty in comparing low S. noctilio catch among different traps. Barnes et al (2014) found that traps baited with fresh host material were attractive to Sirex nigricornis F., which prompted our efforts in 2013 to test different traps baited with host material for capture of S. noctilio or S. nigricornis.…”