James R. Meeker

Effect of Aerosol Surface Lubricants on the Abundance and Richness of Selected Forest Insects Captured in Multiple-Funnel and Panel Traps

ABSTRACT Survey and detection programs for native and exotic forest insects frequently rely on traps baited with odorants, which mediate the orientation of target taxa (e.g., the southern pine beetle, Dendroctonus frontalis Zimmermann) toward a resource (e.g., host material, mates). The influence of trap design on the capture efficiency of baited traps has received far less empirical attention than odorants, despite concerns that intercept traps currently used operationally have poor capture efficiencies for some target taxa (e.g., large woodborers). Several studies have recently demonstrated that treating traps with a surface lubricant to make them “slippery” can increase their capture efficiency; however, previously tested products can be expensive and their application time-consuming. The purpose of this study was to evaluate the effect of alternate, easier to apply aerosol lubricants on trap capture efficiency of selected forest insects. Aerosol formulations of Teflon and silicone lubricants increased both panel and multiple-funnel trap capture efficiencies. Multiple-funnel traps treated with either aerosol lubricant captured significantly more Monochamus spp. and Acanthocinus obsoletus (Olivier) than untreated traps. Similarly, treated panel traps captured significantly more Xylotrechus sagittatus (Germar), Ips calligraphus (Germar), Pissodes nemorensis (Germar), Monochamus spp., A. obsoletus, Thanasimus dubius (F.), and Ibalia leucospoides (Hochenwarth) than untreated traps. This study demonstrates that treating multiple-funnel and panel traps with an aerosol dry film lubricant can increase their capture efficiencies for large woodborers (e.g., Cerambycidae) as well as bark beetles, a weevil, a woodwasp parasitoid and a bark beetle natural enemy (Coleoptera: Cleridae).

Forest composition following overstory mortality from southern pine beetle and associated treatmentsExperiment Station Project 06-08-109 of the Kentucky Agricultural Experiment Station, Lexington, Kentucky.

Bark beetle caused mortality continues to play a critical role in determining the composition and structure of forests in North America, and revegetation dynamics following these disturbances are poorly understood. We assessed forest composition following southern pine beetle, Dendroctonus frontalis Zimmermann, mortality and associated cut and leave suppression, and compared them with undisturbed loblolly pine, Pinus taeda L., stands in Texas. Abundant hardwood regeneration dominated the understory, with little loblolly pine regeneration following either mortality event. Disturbances eliminated loblolly pine dominance in these even-aged stands, thus stratifying forest structure and apparently increasing stem density (stems·ha–1), richness (species·ha–1), and diversity (ha) in the lower strata. Aspect and elevation, presumably through influences on site moisture, were the primary gradients associated with vegetation variation in the canonical correspondence analyses for new regeneration. Mortality from Den...

Predicting Sirex noctilio and S. nigricornis emergence using degree days

The study of temporal interactions between native insects and alien invaders can be facilitated by the ability to forecast adult emergence. We used field‐collected adult emergence data of Sirex noctilio Fabricius (Hymenoptera: Siricidae), a woodwasp native of Eurasia that has recently invaded northeastern North America, and Sirex nigricornis Fabricius, a woodwasp native to North America, to develop and test cumulative degree‐day (CDD) models. Five data sets were collected each in Ontario, Canada (S. noctilio) and Louisiana, USA (S. nigricornis) over 4 years; three data sets were used to develop models and two were used to test them. Males and females of each species were modelled separately. After testing several potential temperatures, chosen thresholds for CDD were 0 °C lower threshold and 25 °C upper threshold for both Sirex spp. We used a three‐parameter Gompertz growth function to model Sirex spp. emergence against CDD. Models predicted 10% emergence of S. noctilio in Ontario after 1 239 and 1 280 CDD, for males (start date = 1 April; R2 = 0.91) and females (start date = 1 April; R2 = 0.86), respectively. Models predicted 10% emergence of S. nigricornis in Louisiana after 3 980 and 5 016 CDD, for males (start date = 1 May; R2 = 0.83) and females (start date = 1 March; R2 = 0.73), respectively. Cumulative degree‐day models predicted 10 and 90% emergence of woodwasp populations with less error (1–13%) than they did 50% emergence (5–27%). For both Sirex spp., male emergence began a few days before and concluded at about the same time as that of females. In southern Ontario, models predict that S. noctilio adults will be in flight between 1 015 and 2 430 CDD (1 April start date for CDD; from early‐July until mid‐September). In Louisiana, models predict that S. nigricornis adults will be in flight between 3 854 and 4 700 CDD (1 May start date for CDD; from early‐October until late‐November).

Detection and Identification of Amylostereum areolatum (Russulales: Amylostereaceae) in the Mycangia of Sirex nigricornis (Hymenoptera: Siricidae) in Central Louisiana

ABSTRACT The woodwasp Sirex noctilio F. (Hymenoptera: Siricidae) has become established in North America.Aprimary tactic for the management of S. noctilio in the southern hemisphere has been the development of a biological control agent, Deladenus siricidicola Bedding. This nematode has a bicyclic life cycle including a mycetophagous free-living and parasitic cycle. During oviposition, female Sirex woodwasps inject a symbiotic fungus. Because D. siricidicola only develops well on Amylostereum areolatum (Chaillet ex Fries) Boidin (Russulales: Amylostereaceae) and North American woodwasps were thought to all have Amylostereum chailletii (Persoon) Boidin as their fungal symbiont, the risk of unintended impacts from D. siricidicola in North America was considered low. Specific polymerase chain reaction primers were designed to amplify the intergenic spacer region of Amylostereum symbionts in a population of the native woodwasp Sirex nigricornis F. located in central Louisiana (i.e., well outside the known distribution of S. noctilio); identity of the symbiont was confirmed by phylogenetic analyses. Overall, 95 out of 100 fungal isolates obtained from the mycangia of S. nigricornis were identified as Amylostereum species. Contrary to expectations, 60% were identified as A. chailletii (N = 60), while 35% were identified as A. areolatum (N = 35). The remaining 5% of these isolates (N = 5) were identified as Bipolaris papendorfii (Aa) Alcorn, Alternaria alternata (Fr.) Keissl, Penicillium marneffei Segretain, Scytalidium cuboideum (Sacc. & Ellis) Sigler & Kang, and Hyphopichia heimii (Pignal) Kurtzman based on sequencing of the internal transcribed spacer (ITS) region. The five non-Amylostereum isolates were likely contaminants during mycangia-spore extraction process. This study confirms the presence of A. areolatum in a population of the native woodwasp S. nigricornis well outside the known distribution of S. noctilio.

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.

Identifying Possible Pheromones of Cerambycid Beetles by Field Testing Known Pheromone Components in Four Widely Separated Regions of the United States

Abstract The pheromone components of many cerambycid beetles appear to be broadly shared among related species, including species native to different regions of the world. This apparent conservation of pheromone structures within the family suggests that field trials of common pheromone components could be used as a means of attracting multiple species, which then could be targeted for full identification of their pheromones. Here, we describe the results of such field trials that were conducted in nine states in the northeastern, midwestern, southern, and western United States. Traps captured 12,742 cerambycid beetles of 153 species and subspecies. Species attracted in significant numbers to a particular treatment (some in multiple regions) included 19 species in the subfamily Cerambycinae, 15 species in the Lamiinae, one species in the Prioninae, and two species in the Spondylidinae. Pheromones or likely pheromones for many of these species, such as 3-hydroxyhexan-2-one and syn- and anti-2,3-hexanediols for cerambycine species, and fuscumol and/or fuscumol acetate for lamiine species, had already been identified. New information about attractants (in most cases likely pheromone components) was found for five cerambycine species (Ancylocera bicolor [Olivier], Elaphidion mucronatum [Say], Knulliana cincta cincta [Drury], Phymatodes aeneus LeConte, and Rusticoclytus annosus emotus [Brown]), and five lamiine species (Ecyrus dasycerus dasycerus [Say], Lepturges symmetricus [Haldeman], Sternidius misellus [LeConte], Styloleptus biustus biustus [LeConte], and Urgleptes signatus [LeConte]). Consistent attraction of some species to the same compounds in independent bioassays demonstrated the utility and reliability of pheromone-based methods for sampling cerambycid populations across broad spatial scales.

Emergence of adult female Sirex nigricornis F. and Sirex noctilio F. (Hymenoptera: Siricidae) coincides with a decrease in daily minimum and maximum temperature

The establishment and spread of Sirex noctilio F. (Hymenoptera: Siricidae), in northeastern North America necessitates reliable monitoring methods for this alien woodwasp pest of Pinus. The native congener, Sirex nigricornis F., is common across the eastern U.S.A. and has been studied as a proxy for S. noctilio. Predicting the emergence of S. noctilio is important for guiding monitoring efforts. Degree‐day models have been developed to predict flight phenology of S. noctilio and S. nigricornis across eastern North America. These model parameters were tested against three years of S. nigricornis collections from two locations in Arkansas. Neither of the proposed models accurately predicted emergence. The emergence of females for both S. noctilio and S. nigricornis was significantly negatively correlated with minimum and maximum temperature, indicating that emergence increases when minimum and maximum temperatures decrease. These results suggest that, as S. noctilio spreads south, where higher mean temperatures are present, it will emerge later in the season as the temperatures decline compared with the current northeastern population. We propose that monitoring for the spread of S. noctilio in the southeastern U.S.A. should begin slightly before daily temperatures are expected to decline (i.e. mid‐September).

The suppression of Dendroctonus frontalis and subsequent wildfire have an impact on forest stand dynamics

ABSTRACT Question: Interacting disturbance effects from Dendroctonus frontalis outbreaks and wildfire are thought to maintain Pinus spp. composition in the southeastern U.S. Our objective was to assess forest composition, structure, and succession following the interaction of two frequently occurring disturbance events in southern Pinus spp. forests: cut-and-leave suppression, a commonly used means for managing D. frontalis outbreaks, and wildfire. Location: Western Gulf Coastal Plain, Louisiana, USA. Method: Pinus taeda stands with cut-and-leave suppression and subsequent wildfire were compared to stands undisturbed by D. frontalis but with the same wildfire events twenty years after Pinus spp. mortality. The woody plant community was assessed in three different size classes and used to predict future forest types with the Forest Vegetation Simulator (50 years). Results: P. taeda is the most abundant (> 50%) species of saw- and poletimber-sizes following cut-and-leave suppression with wildfire and in stands only with fire. Using canonical correspondence analysis, vegetation assemblages were primarily explained by slope position and elevation (7.6% variation explained). Fire intensity and stand age also accounted for variance in the ordination (4.4% and 3.1%, respectively). Dominant and co-dominant P. taeda forest types were predicted by the model to be the most abundant forest types in each disturbance regime. In addition, new regeneration represents high hazard for future mortality from D. frontalis. Conclusion: Our study demonstrates that cut-and-leave suppression with additional wildfire disturbance maintains P. taeda composition, and does not alter forest composition differently from stands receiving only wildfire. As a result, predicted Pinus spp. basal area under both disturbances is great enough to facilitate future bark beetle disturbance. Nomenclature: USDA NRCS (Anon. 2005).

Type of Intercept Trap Not Important for Capturing Female Sirex noctilio and S-nigricornis (Hymenoptera: Siricidae) in North America

ABSTRACT Current detection tools for Sirex noctilio F. (Hymenoptera: Siricidae) in North America are poor. To determine the importance of intercept trap type for capturing females of S. noctilio and its native congener, Sirex nigricornis F., in eastern North America, we report on seven trap comparison studies from different years and geographic locations. Among studies, total numbers of S. noctilio captured were low (mean of ≤1 wasp per trap). Total numbers of S. nigricornis caught were generally greater, and ranged from a mean of 1–13 wasps per trap. Nearly all studies found no significant differences among intercept trap types in the number of woodwasps caught. For future studies, we recommend that either panel or 12-unit Lindgren funnel traps be used to catch S. noctilio or S. nigricornis in eastern North America.

Timing of Adult Emergence and Flight Period of Rhyssa howdenorum (Hymenoptera: Ichneumonidae), a Parasitoid of Sirex nigricornis (Hymenoptera: Siricidae), in Central Louisiana

Following the 2004 detection and subsequent spread of Sirexnoctilio F. (Hymenoptera: Siricidae) in North America, increased attention has been given to furthering our limited understanding of native Sirex spp. and their associated fungal symbionts and natural enemies (Long et al. 2009, Can. Entomol. 141: 153 157). Sirex noctilio, a woodboring wasp (woodwasp), is considered a relatively innocuous insect of pines (Pinus spp.) in its native range (Asia, Europe and North Africa). However, where previously introduced in many areas of the Southern Hemisphere, S. noctilio is noted for its tree-killing ability and is recognized as a worldwide invasive pest of pines (Ciesla 2003, J. For. 101:18 23). The insect has a wide host range, and many North American pines have been demonstrated to be susceptible hosts (Schiff et al. 2012, Can. J. Arthro. Ident. No. 21. 305 p.). To date, the tree-killing impacts of S. noctilio in northeastern North America have been limited compared with the outbreaks and widespread tree mortality events in the Southern Hemisphere, though nearly 20% stem mortality has occurred in places in the Northeast, with mortality occurring predominantly on suppressed, damaged, or debilitated trees (Dodds et al. 2010, Can. J. For. Res. 40:212 223). Due to the existing uncertainties and concern about how S. noctilio might perform in North America in the future (Ryan et al. 2012, Agric. For. Entomol. 14: 187 195), especially if or when it encounters the vast pine forests of the southeastern U.S., studying the native pine siricids and their communities of associated organisms can reduce knowledge gaps about Sirex in general, and help determine consequences of its introduction or invasion. A better understanding of the ecology of native siricids and their natural enemies may also provide tactics and tools for management of S. noctilio