Ken Gibson

GEOGRAPHIC VARIATION IN RESPONSE OF PINE ENGRAVER, Ips pini, AND ASSOCIATED SPECIES TO PHEROMONE, LANIERONE

Lanierone strongly synergized the attraction of male and female Ips pini (Say) to ipsdienol in New York and Wisconsin. Synergy was only weakly significant in Montana and British Columbia and not significant in California. Catches of I. pini in ipsdienol-baited traps were increased 0% ( i.e., nonsignificant) to 9942% by lanierone, with the highest increases in eastern North America. Lanierone had the least effect in California. The effects of lanierone on sex ratios of I. pini in trap catches varied significantly between regions. The addition of lanierone to ipsdienol-baited traps resulted in a general increase in male representation at nine of 12 sites. Ips integer (Eichhoff) was attracted to lanierone alone. Ipsdienol reduced the response of I. integer to lanierone. Enoclerus lecontei (Wolcott) (Cleridae) preferred traps baited with the combination of ipsdienol and lanierone. (R)-(–)-Ipsdienol was attractive to E. sphegeus (F.), Thanasimus undatulus (Say) (Cleridae), and Temnochila chlorodia (Mannerheim) (Trogositidae), while racemic ipsdienol was attractive to E. nigrifrons var. gerhardi Wolc. and Thanasimus dubius (F.). Lanierone had no effect on these species.

A Test of High-Dose Verbenone for Stand-Level Protection of Lodgepole and Whitebark Pine from Mountain Pine Beetle (Coleoptera: Curculionidae: Scolytinae) Attacks

The efficacy of verbenone as a stand-level protectant against mountain pine beetle, Dendroctonus ponderosae Hopkins, attacks was tested in lodgepole and whitebark pine stands at five geographically separated sites, including three consecutive years at one site. Forty and 20 high-dose pouches, with a verbenone emission rate up to 50 mg/d per pouch, were spaced in a grid pattern throughout 0.40-ha plots, replicated up to six times at each site. Although the verbenone treatment did not prevent beetles from dispersing through treated stands, attacking large-diameter trees most frequently, the overall number of trees attacked was, on average, reduced significantly compared with nontreated stands. In a few blocks each year, verbenone-treated plots had more attacked trees than controls. These blocks tended to have a large emerging beetle population, exceeding 140 previously attacked trees within the hectare including and surrounding the treated area. Additional research is needed on the behavioral role of verbenone in mountain pine beetle population dynamics and quantification of the infestation level above which treatment efficacy tends to be reduced.

Quantitative Association of Bark Beetles with Pitch Canker Fungus and Effects of Verbenone on Their Semiochemical Communication in Monterey Pine Forests in Northern Spain

Abstract The association between 11 species of bark beetles (Coleoptera: Scolytinae) and one weevil (Coleoptera: Entiminae) with the pitch canker fungus, Fusarium circinatum Nirenberg and O’Donnell, was determined by crushing beetles on selective medium and histone H3 gene sequencing. Pityophthorus pubescens (Marsham) (25.00%), Hylurgops palliatus (Gyllenhal) (11.96%), Ips sexdentatus (Börner) (8.57%), Hypothenemus eruditus Westwood (7.89%), Hylastes attenuatus Erichson (7.40%), and Orthotomicus erosus (Wollaston) (2.73%) were found to carry the inoculum. In addition, the root weevil Brachyderes incanus L. (14.28%) had the second highest frequency of occurrence of the fungus. The responses of the insects to a range of verbenone doses were tested in field bioassays using funnel traps. Catches of P. pubescens, a species colonizing branch tips of live trees, were significantly reduced in a log-linear dose-dependent relationship. Catches of I. sexdentatus, an opportunistic species normally attacking fresh dead host material, were also gradually reduced with increasing verbenone dose. Catches of Tomicus piniperda L., O. erosus, Dryocoetes autographus (Ratzeburg), H. eruditus, Xyleborus dryographus (Ratzeburg), Hylastes ater (Paykull), Hylurgus ligniperda (F.), H. attenuatus, and B. incanus were not significantly affected by verbenone. The effects of verbenone were consistent with differences in host-age preference. Semiochemical disruption by verbenone in P. pubescens and I. sexdentatus could represent an integrated pest management strategy for the prevention of the spread of pitch canker disease between different stands. However, several species associated with F. circinatum were unaffected by verbenone, not supporting this compound for prevention of the establishment of potential vectors in Northern Spain.

Variables associated with the occurrence of Ips beetles, red turpentine beetle and wood borers in live and dead ponderosa pines with post‐fire injury

Recently, wildfires and prescribed burning have become more frequent in conifer forests of western North America. Most studies examining the impacts of insects on trees with post‐fire injury have focused on contributions to tree mortality. Few studies have examined fire‐caused injuries to estimate the probability of attack by insects. Scant data quantifying insect associations with one another, or with live and dead fire‐injured trees, are available. We examined live and dead trees with varying levels of fire injury in wildfires in Colorado, Montana, Arizona and the Black Hills aiming to determine fire injury associated with insect infestation, co‐occurrence between insects and insect association with live and dead fire‐injured trees. Bole scorch height estimated the likelihood of attack by Ips spp. Diameter at breast height, bole scorch height and crown scorch height estimated the likelihood of attack by Dendroctonus valens LeConte. Diameter at breast height and bole scorch height estimated the likelihood of attack by wood borers. Ips spp., Dendroctonus valens and wood borers were associated with one another. Ips spp. beetles and wood borers were associated with dead fire‐injured trees, whereas D. valens was often associated with live fire‐injured trees. Focusing on certain fire‐caused injuries may identify trees targeted by Ips spp. beetles, Dendroctonus valens and wood borers.