Pine Shoot Research Articles

Shoot feeding ecology of Tomicus piniperda and T. minor (Col., Scolytidae) in southern China

Abstract: The pine shoot beetle, Tomicus piniperda, is causing substantial tree mortality to Pinus yunnanensis in south‐western China, whereas the same species in Europe seldom kills Pinus sylvestris. In order to understand this difference in aggressiveness, we studied the shoot feeding ecology of the pine shoot beetles in Yunnan, and compared it with European results. We found many similarities in the shoot feeding behaviour of T. piniperda, and also that of Tomicus minor, which was common locally. In contrast to Europe, however, the pine shoot beetles in Yunnan seem to be able to predispose the host trees for stem attack by intensive shoot‐feeding. It has also been observed that beetles aggregate in certain trees during shoot feeding, but we could not verify that in our experiment.

Sex attractants and seasonal flight patterns for three Eucosma (Lepidoptera: Tortricidae) species sympatric in eastern pine seed orchards and plantations

AbstractSex attractant blends were developed for monitoring three conifer-feeding species of Eucosma Hübner found in pine seed orchards and plantations in Wisconsin and Ontario. Eucosma monitorana Heinrich, which attacks developing cones of red pine, Pinus resinosa Aiton (Pinaceae), preferred lures containing 100:5:15 (μg blend) of (Z)-9-dodecenyl acetate (Z9-12:Ac), (E)-9-dodecenyl acetate (E9-12:Ac), and (Z)-9-dodecen-1-ol (Z9-12:OH), respectively, over lures without the alcohol or with higher levels of E9-12:Ac. This blend was unattractive to sympatric Eucosma gloriola Heinrich, a species that feeds inside shoots of red pine and eastern white pine, Pinus strobus L. Eucosma gloriola was attracted to a 100:30 blend of Z9-/E9-12:Ac, and adding Z9-12:OH had no significant effect. Eucosma tocullionana Heinrich, which attacks cones of eastern white pine, was attracted equally to 10:3 and 10:5 μg blends of Z9-/E9-12:Ac, and adding Z9-12:OH had no effect. A ratio as low as 1:0.3 was attractive to E. tocullionana but not to sympatric E. gloriola, which preferred a 100-fold higher dosage of the same blend. The seasonal flight periods of the three species overlapped in all study areas. The flight of E. gloriola usually peaked in late May slightly before that of E. monitorana while the flight of E. tocullionana peaked about 1–3 weeks later. The results indicate that sex pheromones, seasonal flight periods, and host preferences are isolating mechanisms for these closely related sympatric species.

Multispecies trapping of six pests of scots pine in Sweden and Poland

Abstract: Multispecies sex pheromone trapping (trapping of more than one species in the same trap) for the pine shoot moth Rhyacionia buoliana, the pine moth, Dendrolimus pini, the nun moth, Lymantria monacha, the pine beauty moth, Panolis flammea and the pine sawflies Diprion pini and Neodiprion sertifer was evaluated. The catch from traps baited with the pheromone of a single species was compared with the catch from traps baited with pheromones for several species. The catch in the multispecies traps was significantly reduced in comparison with the single species traps for Dendrolimus pini, L. monacha and N. sertifer. Neodiprion sertifer was most likely inhibited by the Diprion pini pheromone. A follow-up study of Dendrolimus pini and L. monacha showed no pheromonal interference between them. Further studies are needed to evaluate the feasibility of multispecies monitoring. However, for practical applications a slight decrease in catch, due to pheromonal interference, could probably be tolerated as long as the catch reflects total population density.

Nonindigenous species introductions: a threat to Canada's forests and forest economy1

When organisms are moved from their natural range to new ecosystems, they are considered nonindigenous, invasive, or exotic species. Movement of exotic or native species may be international or from areas within Canada. Historically, Canada's forests have felt the effects of nonindigenous species introductions, as for example, Dutch elm disease, white pine blister rust, gypsy moth, and pine shoot beetle. With changes in global trade patterns, novel introductions will continue to occur. Although most of the research and regulatory efforts to control the movement of nonindigenous species has focused on insects, projects are underway to study fungal organisms and their association with insect vectors. International quarantine standards are being developed to minimize the risk associated with solid wood packing materials, a major entry pathway for nonindigenous organisms. Research needs include the development of enhanced detection capabilities, improved diagnostic tools, effective mitigation measures, as well as socio-economic impact assessments and basic biological information about nonindigenous species and their interactions with hosts.

Ethylene metabolism in Scots pine (Pinus sylvestris) shoots during the year.

Ethylene evolution, concentrations of 1-aminocyclopropane-1-carboxylic acid (ACC) and ACC conjugates, activities of ACC synthase and ACC oxidase, and cambial growth as measured by tracheid production were monitored from November to July in 1-year-old shoots, and between July and September in current-year shoots, of Scots pine (Pinus sylvestris L.). Needles, buds and four stem parts (cortex, phloem, cambial region and mature xylem) were surveyed. Ethylene evolution was quantified by gas chromatography. Free ACC and bound ACC (after acidic hydrolysis of ACC conjugates) were quantified by combined gas chromatography-mass spectrometry, with [2H]ACC as an internal standard. Activities of ACC synthase and ACC oxidase were measured in crude protein extracts. We detected high activities of ACC synthase in needles and buds, but not in stem fractions except the phloem. In July, during the period of intensive shoot growth, we found ACC only in buds and needles. In contrast, ACC oxidase activity was high in stem tissues, particularly in the cambial region during the period of rapid tracheid production, but no ACC oxidase activity was detected in needles and buds. Nevertheless, needles evolved large amounts of ethylene. Ethylene was produced by all stem fractions, and the peak rate of ethylene evolution in the cambial region coincided with the period of maximal tracheid production. Conjugated ACC was present in every fraction except mature xylem. The concentration of conjugated ACC decreased when rates of tracheid production and ethylene evolution were high, suggesting that conjugated ACC may serve as a source for ACC in the cambial region. The regulation of ethylene biosynthesis in Scots pine shoots is discussed.

Threats to pine stands by the pine shoot beetles Tomicus piniperda (L.) and Tomicus minor (Hart.) (Col., Scolytidae) around a sawmill in southern Poland

Forest stands growing around sawmills are especially exposed to damage due to the feeding by the pine shoot beetles Tomicus piniperda (L.) and Tomicus minor (Hart.) (Col., Scolytidae) in the pine shoots, causing a considerable loss of increment. The purpose of this study was to determine the relation of the distance zone of a stand from a sawmill to the density of the pine shoot fall, width of annual rings, and pine stand quality. The investigations were carried out between 1992 and 1996 in a Pinus silvestris–Abies alba stand adjacent to a sawmill in the Zagnańsk Forest District. In the investigated stand, eight zones situated at different distances from the sawmill were marked out, in which the fallen pine shoots were collected and dendrometric measurements taken. The study results showed that the pine shoot fall in the area up to 300 m away from the sawmill was significantly greater than the fall in zones situated further away. In addition, the mean current annual and 10‐year radial increments at breast height were significantly smaller, and the pine stand quality class was lower within that area. The radial increment at breast height in the area up to 300 m away from the sawmill was almost twice as low as that in the control area, and about 40% lower than the increment in the area situated 300–900 m away. The increment pattern of pine in this area differed from that of fir, suggesting that the incremental loss and lower pine stand quality are the result of long‐term feeding of the pine shoot beetles in the pine shoots. These results indicate that other causes, such as differences in site class, climatic factors or air pollution, can be excluded.

Survey of Shoot Damage Caused by the Exotic Pine Shoot Beetle in Michigan Pine Stands

Abstract The exotic pine shoot beetle, Tomicus piniperda [L.] (Coleoptera: Scolytidae) is a Eurasian pest of pines that was first discovered in North America in 1992 near Cleveland, Ohio. It has since been found in at least 72 counties in Michigan, 285 additional counties in 11 other north central and eastern states, and the provinces of Ontario and Quebec. We counted injured shoots along linear transects in ten stands of Scotch (Pinus sylvestris L.), red (Pinus resinosa Aiton), and jack pine (Pinus banksiana Lambert) in lower Michigan (30 stands total) to estimate the frequency of shoot damage attributable to pine shoot beetle, other shoot-feeding insects, weather, and other damaging agents from 1997 to 1999. Fifteen of the stands were located in southwestern counties where pine shoot beetle has been established for at least 8 to 10 yr. The other 15 stands were in northern counties where pine shoot beetle establishment is more recent. In the southwestern stands, pine shoot beetle killed significantly more shoots in Scotch pine stands than in red or jack pine stands, and injured more shoots in Scotch pine stands than all other insects combined. Two of these Scotch pine stands were near an area with an abundance of Scotch pine brood material available to parent beetles. Damage in these two stands averaged roughly 10 to 12 shoots per m2 in 1998 and 1999, compared with 0.6 to 1.6 shoots per m2 in other Scotch pine stands, and less than 0.2 shoots per m2 in nearby red or jack pine stands. Pine shoot beetle was at very low or undetectable levels in northern stands in all years. Shoots injured by three other shoot-feeding insects were occasionally encountered, most often in red pine stands, but caused an insignificant amount of damage. With the exception of the southwestern Scotch pine stands, most of the shoot damage, particularly in northern jack pine stands, was attributable to squirrels or abiotic factors such as wind, ice or snow. North. J. Appl. For. 18(4):101–109.

Latent Infection of Austrian and Scots Pine Tissues by Sphaeropsis sapinea.

This study documents latent infection of Austrian and Scots pine tissues by Sphaeropsis sapinea, the causal agent of Sphaeropsis tip blight disease. Symptomless shoots from diseased or apparently healthy Austrian and Scots pine trees were cultured and analyzed for the presence of S. sapinea. Nearly half of the sampled Austrian and Scots pine trees that appeared to be completely healthy had detectable latent S. sapinea infections. More than half of the symptomless shoots on visibly diseased Austrian and Scots pine trees were also latently infected with S. sapinea. S. sapinea was isolated from symptomless shoot stems, needles, buds, immature cones, and male flowers. In symptomless infected shoots, the fungus was primarily associated with the bark and phloem tissues. Six isolates of S. sapinea from symptomless Austrian and Scots pine shoot tissues were pathogenic on Austrian pine seedlings in the greenhouse. The presence of S. sapinea in symptomless tissues of tip blight-diseased trees has important implications for disease management.

Shoot structure and photosynthetic efficiency along the light gradient in a Scots pine canopy.

We examined the effects of structural and physiological acclimation on the photosynthetic efficiency of Scots pine (Pinus sylvestris L.) shoots. We estimated daily light interception (DLI) and photosynthesis (DPHOT) of a number of sample shoots situated at different positions in the canopy. Photosynthetic efficiency (epsilon) was defined as the ratio of DPHOT to the potential daily light interception (DLI(ref)) defined as the photosynthetically active radiation (PAR) intercepted per unit area of a sphere at the shoot location. To calculate DLI(ref), DLI and DPHOT, the radiation field surrounding a shoot in the canopy was first modeled using simulated directional distributions of incoming PAR on a clear and an overcast day, and estimates of canopy gap fraction in different directions provided by hemispherical photographs. A model of shoot geometry and measured data on shoot structure and photosynthetic parameters were used to simulate the distribution of PAR irradiance on the needle surface area of the shoot. Photosynthetic efficiency (epsilon) was separated into light-interception efficiency (epsilon(I) = DLI/DLI(ref)) and conversion efficiency (epsilon(PHOT) = DPHOT/DLI). This allowed us to quantify separately the effect of structural acclimation on the efficiency of photosynthetic light capture (epsilon(l)), and the effect of physiological acclimation on conversion efficiency (epsilon(PHOT)). The value of epsilon increased from the top to the bottom of the canopy. The increase was largely explained by structural acclimation (higher epsilon(I)) of the shade shoots. The value of epsilon(PHOT) of shade foliage was similar to that of sun foliage. Given these efficiencies, the clear-day value of DPHOT for a sun shoot transferred to shade was only half that of a shade shoot at its original position. The method presented here provides a tool for quantitatively estimating the role of acclimation in total canopy photosynthesis.

Host resistance in defoliated pine: effects of single and mass inoculations using bark beetle‐associated blue‐stain fungi

Abstract1 In 1996, 7000 ha of pine forests were defoliated by the pine looper Bupalus piniaria in south‐western Sweden.2 The susceptibility of trees of different defoliation classes (0, 30, 60, 90 and 100% defoliation) to beetle‐vectored blue‐stain fungi was tested in inoculation experiments. Forty and 120‐year‐old Scots pine trees were inoculated with ‘single’, i.e. a few inoculations of Leptographium wingfieldii and Ophiostoma minus, two blue‐stain fungi associated with the pine shoot beetle Tomicus piniperda. The young trees were also ‘mass’ inoculated with L. wingfieldii at a density of 400 inoculation points per m2 over a 60 cm stem belt.3 Host tree symptoms indicated that only trees with 90–100% defoliation were susceptible to the mass inoculation.4 Single inoculations did not result in any consistent differences in fungal performance between trees of different defoliation classes, regardless of inoculated species or tree age class.5 Leptographium wingfieldii produced larger reaction zones than O. minus, and both species produced larger lesions in old than in young trees.6 As beetle‐induced tree mortality in the study area occurred only in totally defoliated stands, mass inoculations seem to mimic beetle‐attacks fairly well, and thus seem to be a useful tool for assessing host resistance.7 As even severely defoliated pine trees were quite resistant, host defence reactions in Scots pine seem to be less dependent on carbon allocation than predicted by carbon‐based defence hypotheses.

Evaluation of the importance of acclimation of needle structure, photosynthesis, and respiration to available photosynthetically active radiation in a Scots pine canopy

We analyzed the combined effect of differences in the photosynthetic light response curve and in the distributions of photosynthetically active radiation (PAR) irradiance within the canopy on the CO2 exchange rates of Scots pine (Pinus sylvestris L.) shoots. Nitrogen concentration did not vary with depth within the canopy, but leaf mass per area (LMA) ranged from 58.2 to 95.2 g·m–2 (all needle age-classes pooled) and increased with increasing available PAR. The photosynthetic light response curves of 75 randomly sampled, 1-year-old shoots (with a fixed structure) were measured in the laboratory. No statistically significant differences in photosynthetic parameters or stomatal conductance either on an area or mass basis were detected between the top, middle, and bottom zones of the canopy. However, a significant decrease occurred in the area-based dark respiration rate (Rd) with increasing depth in the canopy. The area-based maximum CO2 exchange rate was weakly correlated with needle nitrogen content (Narea) and LMA, whereas Rd showed a higher correlation with both Narea and LMA. Estimates of the CO2 exchange rate over a day (24 h) in July suggest that the apparently small differences in mean light response curves of the canopy zones are reflected in the enhanced performance of shade needles in low light conditions because of reduced respiration costs. Based on our results, structural acclimation of needles along the light gradient, rather than changes in biochemical machinery, appears to be the more important acclimation process in Scots pine.

Preference of Tomicus piniperda (Coleoptera: Scolytidae) parent adults and shoot-feeding progeny adults for three pine species

AbstractHost preference of the pine shoot beetle, Tomicus piniperda (L.), was investigated in two laboratory choice test studies using red pine (Pinus resinosa Ait.) (Pinaceae), jack pine (Pinus banksiana Lamb.), and Scotch pine (Pinus sylvestris L.). Host preference of parent adult beetles was evaluated using freshly cut, similarly sized logs in a wind tunnel. Parent beetles colonized Scotch pine logs significantly more often when given a choice of Scotch pine and either red pine or jack pine logs, but did not show a preference when presented with red pine and jack pine logs. Host preference of progeny adults was tested in a laboratory bioassay using current-year pine shoots. Shoot-feeding progeny adults initiated tunnels in jack pine shoots significantly more often than in Scotch pine and red pine shoots, and preferred Scotch pine over red pine shoots. Shoots with diameters of 0.4–0.5 cm were attacked most frequently, regardless of species. Results suggest that the two North American pines are suitable hosts, but T. piniperda may be most likely to colonize Scotch pine, a European species. Efforts to detect or monitor T. piniperda populations in the Great Lakes and northeastern regions should focus on areas with abundant Scotch pine brood material. Progeny that emerge from brood material, however, may be as likely to shoot-feed in jack pine as in Scotch pine.

The use ofBacillus thuringiensis on Forest Integrated Pest Management

Bacillus thuringiensis is a major microbial insecticide and a source of genes encoding several proteins toxic to insects. In this paper the authors give a brief summary ofBacillus thuringiensis used on the integrated pest management in forestry. The derivatives of Bt strain HD1 subspkurstaki have been widely used to control the forest pests such as the gypsy moth (Lymantria dispar), spruce budworm (Choristoneura fumiferana), the pine processionary moth (Thaumetopoea pityocampa), the European pine shoot moth (Rhyacionia buoliana) and the nun moth (Lymantria monacha). Some progresses of transferring and expressing Bt toxin gene in forest trees are offered with a discussion on the limits and future prospects of using Bt products in forestry.

Effect of maturation feeding period on survival of Tomicus piniperda (Coleoptera: Scolytidae)

AbstractCallow adults of the pine shoot beetle, Tomicus piniperda L., were fed shoots of Scots pine, Pinus sylvestris L. (Pinaceae), to investigate the influences of shoot age and feeding duration on survival and weight of callow adults and to characterize the relationship between the volume of shoot tissue excavated and weight gain. Heavier callow adults had better survival than lighter ones, and survival was higher on current-year shoots than on 1-year-old shoots. A significant relationship was observed between the amount of tissue excavated by callow females on current-year shoots and their body weight gain, a trend not observed in callow males. These results suggest that beetle weight and survival may be reduced when availability of current-year shoots during maturation feeding is limited because of competition (i.e., during population outbreaks), thus negatively affecting the production of future generations.

Effects of growth and virulence of associated blue‐stain fungi on host colonization behaviour of the pine shoot beetles Tomicus minor and T. piniperda

The pine shoot beetles Tomicus minor and T. piniperda are common in the Nordic countries. Of these, T. piniperda may attack and kill living but severely stressed trees, whereas T. minor has never been reported to be individually responsible for killing live trees. Both species are associated with blue‐stain fungi: T. minor with Ophiostoma canum and T. piniperda with Leptographium wingfieldii and Ophiostoma minus. The growth of these fungi was studied in phloem and sapwood of live Scots pine trees, on malt agar, and on malt agar under oxygen‐deficient conditions. Leptographium wingfieldii was more virulent (i.e. caused more extensive host symptoms) grew more quickly on malt agar, and was less affected by oxygen‐deficient growth conditions than either O. minus or O. canum. Ophiostoma canum was least virulent. In low‐density inoculations it induced lesions similar to those induced by sterile control inoculations; it grew very slowly on malt agar and stopped growing after ≈30 mm under oxygen‐deficient conditions. Ophiostoma minus was intermediate in all respects. The different virulence of the blue‐stain fungi associated with the two pine shoot beetles may explain the lower level of aggressiveness in T. minor.

Evolving Management Strategies for a Recently Discovered Exotic Forest Pest: The Pine Shoot Beetle, Tomicus Piniperda (Coleoptera)

Established populations of the Eurasian pine shoot beetle (Tomicus piniperda (L.); Coleoptera: Scolytidae) were first discovered in North America in Ohio in 1992. As of 31 December 2000, T. piniperda was found in 303 counties in 12 US states (Illinois, Indiana, Maine, Maryland, Michigan, New Hampshire, New York, Ohio, Pennsylvania, Vermont, West Virginia, and Wisconsin) and in 43 counties in 2 Canadian provinces (Ontario and Quebec). A federal quarantine imposed in November 1992 regulates movement of pine (Pinus) trees, logs, and certain pine products from infested to uninfested areas within US. The forest products, Christmas tree, and nursery industries are affected by the quarantine. This paper summarizes information on the discovery and spread of T. piniperda in North America, survey efforts, recent interception history, development and changes in the federal quarantine, development of a national compliance management program, and extension and research efforts.

BROOD PRODUCTION AND SHOOT FEEDING BY TOMICUS PINIPERDA (COLEOPTERA: SCOLYTIDAE)

AbstractBrood production and shoot feeding by the pine shoot beetle, Tomicus piniperda (L.), were studied over 3 years in naturally infested plantations of Scots pine, Pinus sylvestris L. (Pinaceae), near Guelph and Waterloo, Ontario, using trap-logs. Adult beetles produced a single brood in 1996 and 1997 and two broods in 1999. Galleries for the first brood were all initiated under the bark over a 2- to 3-week period from mid-April to early May. The lone second brood occurred in early June. In all years, eggs were present by late April, larvae by mid-May, pupae by late June, and new adults by mid-July. Complete development (egg–pupa) required 12–13 weeks for the first brood and 8 weeks for the second brood. First-brood adults emerged over a 2- to 3-week period from early to mid-July in all years, with second-brood adults emerging in late July. The effective heat sums (degree-days (°d) > developmental-threshold temperature) were 77–79 °d for eggs, 267–293 °d for the larval stage, 139–152 °d for the pupal stage, and 43.2 °d for the pre-emergence stage, depending on the developmental-threshold temperature used. The total heat sums for the first brood (1249.8 ± 73.3 °d > 0 °C) were larger that those required for the second brood (856.4 ± 124 °d > 0 °C). Overall, values for first-brood development were similar to those calculated for European and Asian populations. Pine shoots in the upper tree crowns were used by adult beetles for maturation feeding between late July and late September in both 1995 and 1996. The re-emerging parental adults fed upon 1-year-old shoots, whereas newly emerging adults fed primarily upon current-year shoots. The beetles appeared to move to overwintering sites in late October to November, and no adults were found overwintering in shoots on the trees or the ground. Our results parallel those obtained by others under similar climatic conditions in Europe, and can be used to improve the management and regulation of this species as it becomes established in our native pine forests.

The electrical impedance spectroscopy of Scots pine (Pinus sylvestris L.) shoots in relation to cold acclimation.

Electrical impedance spectroscopy (EIS) was applied to stems of Scots pine (Pinus sylvestris L.) in a provenance field trial during frost hardening to find an EIS parameter for assessing frost hardiness (FH) without a controlled freezing test. The FH of stems and needles assessed by controlled freezing tests was compared with the equivalent circuit EIS parameters of a distributed model of stems (not exposed to controlled freezing treatment) and with dry matter (DM) content of stems. Significant differences in the equivalent circuit parameters, FH and DM content were found between provenances. The relaxation time (tau(1)), describing the peak of the high frequency arc of the impedance spectrum, and the intracellular resistance (r(i)) of stems increased with increasing FH. According to the linear regression, the coefficient of determination (R(2)) between the FH of stems and needles with tau(1) of the stem was 0.87 and 0.89, and with r(i) of the stem 0.74 and 0.85, respectively. The relation between FH and tau(1) changed with the degree of hardiness. The highest coefficient of determination was 0.95 in September when the FH of needles, ranging from -10 degrees C to -25 degrees C, was predicted with an accuracy of +/-2.0 degrees C. The resistance parameter r(2), describing the width of the low frequency arc of the impedance spectrum, decreased prior to and during the initial hardening: significant differences were found between provenances. This indicates that r(2) was not related to frost hardening per se. It is concluded that it is possible to distinguish the hardening patterns of different provenances by tau(1) in the rapid phase of hardening without controlled freezing tests.

ELECTROPHYSIOLOGICAL AND BEHAVIOURAL RESPONSES OF TOMICUS PINIPERDA AND TOMICUS MINOR (COLEOPTERA: SCOLYTIDAE) TO NON-HOST LEAF AND BARK VOLATILES

AbstractLeaf and bark volatiles from non-host birches, Betula pendula Roth. and Betula pubescens Ehrh. (Betulaceae), and aspen, Populus tremula L. (Salicaceae), were tested on spring-dispersing Tomicus piniperda (L.) and Tomicus minor (Hart.) by gas chromatographic – electroantennographic detection (GC–EAD) and by attractant-baited traps in southern Sweden. GC–EAD analysis of the head-space volatiles from fresh bark chips of B. pendula revealed two green leaf alcohols, 1-hexanol and (Z)-3-hexen-1-ol, that consistently elicited antennal responses by T. piniperda and T. minor. Further analyses with synthetic mixtures showed that the antennae of these two Tomicus species also responded to other green leaf alcohols, such as (E)-2-hexen-1-ol found from the non-host leaves, and C8-alcohols, 3-octanol and 1-octen-3-ol, from bark of non-host birches and aspen. No antennal responses of the Tomicus species were observed to green leaf C6-aldehydes and C6-acetate or to non-host bark volatiles like trans-conophthorin, benzaldehyde, salicylaldehyde, and benzyl alcohol. In field trapping experiments, blends of electrophysiologically active green leaf alcohols or C8-alcohols resulted in reductions (> 60%) in the number of T. piniperda captured compared with that for the kairomone-baited trap. When these two blends were combined, trap catch was further reduced (90%), which was not significantly different from that for the blank control. Neither the blend of two green leaf aldehydes plus the acetate nor the bark compounds trans-conophthorin or benzyl alcohol reduced trap catches. Tomicus minor had a response pattern similar to that of T. piniperda. Hylurgops palliatus (Gyll.) (Coleoptera: Scolytidae) was attracted to the combination of kairomone and verbenone but not to kairomone and was not affected by the blends of green leaf volatiles. Our results suggest that selected leaf–bark C6-alcohols and the bark C8-alcohols may have potential in developing semiochemical-based management programs against both pine shoot beetles by repelling them from suitable breeding and feeding sites.

DISPERSAL OF TOMICUS PINIPERDA (COLEOPTERA: SCOLYTIDAE) FROM OPERATIONAL AND SIMULATED MILL YARDS

AbstractThe pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that is regulated by federal quarantines in the United States and Canada. Mark–release–recapture experiments were performed with infested logs coated with fluorescent powder to determine if overwintering beetles in logs would leave a mill yard if infested logs were transported to sawmills in uninfested areas. Overwintering T. piniperda adults were marked with powder as they emerged in spring. Dispersal studies were conducted in four simulated mill yards and five operational sawmills to determine whether T. piniperda would colonize only the log pile in which they overwintered, fly to nearby log piles, or disperse beyond the mill yard. Each simulated mill yard was composed of 36 uninfested red pine logs, Pinus resinosa Ait. (Pinaceae), and 12 α-pinene-baited funnel traps set up to 100 m from a central release pile of six uninfested red pine and nine infested logs of Scotch pine, Pinus sylvestris L. At the five operational sawmills, baited funnel traps were set up to 400 m outside of each mill yard. Overall, 482 T. piniperda galleries were found on the experimental logs recovered from the four simulated mill yards combined. Tomicus piniperda adults dispersed and attacked the most distant logs at 100 m from the release point in the simulated mill yards. Likewise, adults were captured in baited funnel traps at distances up to 230 m in simulated mill yards and 250 m around operational sawmills. Although numbers of recaptured T. piniperda were generally low, in all cases some adults dispersed outside the mill yards despite the presence of abundant suitable breeding material. Therefore, logs containing overwintering adults pose a risk of spreading T. piniperda if not processed prior to initiation of spring flight.