Effects of Ethanol and α-Pinene in a Generic Trap Lure Blend for Pine Bark and Wood-Boring Beetles in Southeastern United States

Managers of detection programs for bark and wood-boring beetles require cost-effective trap lure combinations that maximize species detections. A trapping study was conducted in 2012 to determine the effects of ethanol and α-pinene lures on beetle catches in traps baited with ipsenol and ipsdienol lures in a stand of Pinus taeda L. in north-central Georgia. Traps with all four compounds worked well for 20 of 25 species of bark and wood-boring beetles, and associated predators. Catches of Acanthocinus obsoletus (LeConte) and Monochamus titillator (F.) (Cerambycidae), Hylastes porculus Erichson, Hylastes salebrosus Eichhoff, Hylobius pales (Herbst), Orthotomicus caelatus (Eichhoff) (Curculionidae), Thanasimus dubius (F.) (Cleridae), and Temnoscheila virescens (F.) (Trogossitidae) in baited traps increased with the addition of ethanol and α-pinene with maximum catches in traps baited with all four compounds. Catches of Ips avulsus (Eichhoff) (Curculionidae) decreased with the addition of both compounds; the lowest numbers of I. avulsus and Ips grandicollis (Eichhoff) were caught in traps baited with all four compounds. α-Pinene increased catches of Buprestis lineata F. (Buprestidae), Ips calligraphus (Germar), Pachylobius picivorus (Germar) (Curculionidae), Corticeus spp. (Tenebrionidae), Lasconotus spp., and Pycnomerus sulcicollis LeConte (Zopheridae); ethanol had no effect on these species. Ethanol increased trap catches of Curius dentatus Newman (Cerambycidae), Dryoxylon onoharaense (Murayama) (Curculionidae) and Platysoma spp. (Histeridae); α-pinene reduced catches. The data suggest that ethanol and α-pinene should be retained with ipsenol and ipsdienol as a generic trap lure blend for pine bark and wood-boring beetles in southeastern United States.

Trap Height Affects Catches of Bark and Woodboring Beetles (Coleoptera: Curculionidae, Cerambycidae) in Baited Multiple-Funnel Traps in Southeastern United States

In north-central Georgia, trap height affected catches of some species of bark and woodboring beetles (Coleoptera) in traps baited with lures used in surveillance programs to detect non-native forest insects. Traps were placed within the canopy and understory of mature oak trees (Quercus spp.) with collection cups placed 18–23 m above ground level (AGL), and 0.3–0.5 m AGL, respectively. Traps were baited with ethanol to target ambrosia beetles (Curculionidae: Scolytinae) in one experiment, ethanol + syn-2,3-hexanediol + racemic 3-hydroxyhexan-2-one + racemic 3-hydroxyoctan-2-one to target hardwood woodborers (Cerambycidae) in a second experiment, and α-pinene + racemic ipsenol + racemic ipsdienol to target pine bark beetles (Curculionidae) and woodborers (Cerambycidae) in a third experiment. Canopy traps were more effective than understory traps for detecting Cnestus mutilatus (Blandford) (Curculionidae), Neoclytus scutellaris (Olivier), and Monochamus titillator (F.) (Cerambycidae). The reverse was true for Xylosandrus crassiusculus (Motschulsky), Dendroctonus terebrans (Olivier) (Curculionidae), and Neoclytus acuminatus (F.) (Cerambycidae). Catches of a third group which included Hylobius pales (Herbst), Ips grandicollis (Eichhoff) (Curculionidae), Neoclytus mucronatus (F.), and Anelaphus pumilus (Newman) (Cerambycidae) were largely unaffected by trap height. Similar patterns were noted for species of Cleridae, Scarabaeidae, Trogossitidae, and Zopheridae but not Histeridae or Tenebrionidae (Coleoptera). Catches of the bee assassin Apiomerus crassipes (F.) (Hemiptera: Reduviidae) in traps baited with the hardwood borer blend were greater in canopy traps than in understory traps.

Hylobius pales. [Distribution map].

A new distribution map is provided for Hylobius pales (Herbst). Coleoptera: Curculionidae. Hosts: Pinus spp. Information is given on the geographical distribution in North America (Canada, Alberta, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, USA, Alabama, Arkansas, Connecticut, District of Columbia, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Texas, Vermont, Virginia, Washington, West Virginia, Wisconsin), Central America and Caribbean (Puerto Rico).

Effects of Prescribed Fire and Fire Surrogates on Saproxylic Coleoptera in the Southern Appalachians of North Carolina

We examined the effects of forest management practices (prescribed burning, mechanical, and prescribed burn plus mechanical) on saproxylic forest Coleoptera in the southern Appalachian Mountains of North Carolina. During the 2-yr study, we captured 37,191 Coleoptera with baited multiple-funnel traps and pipe traps, comprising 20 families and 122 species that were used for our analysis. Saproxylic beetle numbers increased greatly from the first year to the second year on all treatments. Species richness and total abundance of Coleoptera were not significantly affected by the treatments, but several families (e.g., Elateridae, Cleridae, Trogositidae, Scolytidae) were significantly more abundant on treated plots. Abundances of many species, including various species of Scolytidae were significantly affected by the treatments. However, these scolytids (Hylastes salebrosus Eichoff, Ips grandicollis Eichoff, Xyloborinus saxeseni Ratzburg, Xyleborus sp., Xyleborus atratus Eichoff) did not respond in the same way to the treatments. Likewise, other Coleoptera such as Pityophagus sp. (Nitidulidae), Hylobius pales Herbst (Curculionidae), and Xylotrechus sagittatus Germar (Cerambycidae) also varied in their responses to the treatments. Species richness was not significantly different for the spring 2003 trapping seasons, but the fall 2003 sample had a higher number of species on mechanical shrub removal only and mechanical shrub removal plus prescribed burning plots compared with controls. Linear regression analysis suggests that increased dead wood caused by hot fires on mechanical plus burn and burn only treatments resulted in increases among various Coleoptera families and species. We saw no evidence that the treatments negatively impacted saproylic species and in most cases they benefited from the disturbances.

Behavioral Response by Hylobius pales, Pachylobius picivorus (Coleoptera: Curculionidae) and Xylotrechus sagittatus (Coleoptera: Cerambycidae) to Trap Visual and Olfactory Cues and an Estimate of Trap Efficiency

A modified Tilles trap and the pyramidal Tedders trap alone or in combination with 2-way pitfall traps were used in north Florida to determine trap capture efficiency and the roles of visual and olfactory cues in the behavior of 2 species of root-feeding weevils, Hylobius pales (Herbst) and Pachylobius picivorus (Germar) (Coleoptera: Curculionidae), and a cerambycid, Xylotrechus sagittatus (Germar) (Coleoptera: Cerambycidae). The 3 species responded strongly to olfactory cues provided by a 5:1 ratio of ethanol and turpentine. Visual cues followed olfactory cues in the host finding and selection hierarchy and were important in the trap response of H. pales and X. sagittatus, but less important for P. picivorus. The Tedders trap captured 18% of the total of the P. picivorus, >70% of the H. pales and >80% of the X. sagittatus. Response to odor and visual cues was more directed toward the point source in H. pales when compared with P. picivorus. More than 80% of P. picivorus landed some distance away from the trap and moved toward it. In contrast, less than 30% of H. pales landed away from or failed to enter the Tedders trap. The numbers of X. sagittatus trapped were greater in traps that were elevated off the ground. Response to the modified Tilles trap confirmed and supported the findings in the other trap configurations. Use of this methodology has potential for monitoring populations of these beetles and determining the behavior and biology of other insect species.

Pine Weevil (Coleoptera: Curculionidae) Population Monitoring in Christmas Trees Using Volatile Host Compounds

The eastern pine weevil, Pissodes nemorensis Germar, and the pales weevil, Hylobius pales (Herbst), are major pests of pine production in eastern North America. Ethanol- and turpentine-baited pitfall traps and flight traps, and pit traps baited with fresh pine billets, were used to characterize weevil species composition in north-central Kentucky (USA) and assess seasonal activity by exploiting the weevils' attraction to host plant volatiles. During the 1998 growing season, P. nemorensis was the predominant species, comprising over 95% of the total trap catch for the season. Weevils were most responsive to fresh pine billets in pit traps, followed by ethanol- and turpentine-baited flight traps, and ethanol- and turpentine-baited pitfall traps. The sex ratio of P. nemorensis captured in pit traps was male biased, and in pitfall traps it was weakly female biased. Flight trap catch in traps placed 0.8 m above ground level was female biased. More weevils were captured in flight traps at 0.8 m than in flight traps at 1.6 m. Catches were greatest in traps placed perpendicular to the slope. Although H. pales was present at the site, numbers captured were too low to statistically assess trap efficacy.

Evaluation of Natural Products as Antifeedants for the Pales Weevil (Coleoptera: Curculionidae) and as Fungitoxins for Leptographium procerum

Four natural plant compounds (limonin, S (+) and R (−) carvone, and cucurbitacin) and one insect pheromone (verbenone) were evaluated for antifeedant activity against the pales weevil, Hylobius pales (Herbst), on Pinus strobus seedlings and for toxic activity against the pathogenic fungus, Leptographium procerum (Kendrick) Wingfield, which is vectored by H. pales to P. strobus. All compounds demonstrated significant antifeedant activity in a choice test on treated pine seedlings, but none completely eliminated feeding. Only cucurbitacin elicited a linear dose-response relationship, with significant activity occurring at concentrations as low as 0.10 μg/ml. The other compounds significantly reduced feeding at concentrations as low as 1 μg/ml (the lowest concentration at which they were tested). Total feeding activity was unaffected for all but one treatment (S (+) carvone at 1 μg/ml) when compared with feeding on the untreated control seedlings. It is, therefore, unlikely that the compounds in this study were toxic to the weevils during the 2 d evaluation period. In the fungitoxin test, all compounds except cucurbitacin suppressed germination of L. procerum spores. R (−) carvone was the most effective, allowing only 5% germination at 1 μg/ml, compared to 96% germination in the water solvent.