Effects of C10‐ and C12‐chain length alkyl analogs of monochamol on attraction of longhorn pine sawyer Monochamus saltuarius (Coleoptera: Cerambycidae)

The aggregation pheromone of Monochamus (Coleoptera: Cerambycidae) beetles, 2‐(undecyloxy) ethanol (hereafter referred to as monochamol), has gained considerable attention because of its usefulness in monitoring and population control of pine sawyer beetles. The hydroxyether structural motif is conserved in pheromones of the subfamily Lamiinae of the Cerambycidae. In this study, we investigated the effects of C10‐ and C12‐chain length alkyl analogs of monochamol, 2‐(decyloxy) ethanol and 2‐(dodecyloxy) ethanol, on attracting M. saltuairus in Andong, Gyeongsangbuk‐do, Korea. The C10 and C12 analogs attracted M. saltuarius when used in combination with α‐pinene and ethanol, but the responses of these alkyl chain analogs were lower than those of monochamol. Furthermore, the addition of either C10 or C12 analog to the use of monochamol with α‐pinene and ethanol had no effect on attraction of M. saltuarius, indicating high sensitivity of M. saltuarius to monochanol. Taken together, the results of this study suggest that chemical communication within a Monochamus species depends not only on monochamol, but also on other semiochemicals.     

Field evaluation on the synergistic attractiveness of 2‐(1‐undecyloxy)‐1‐ethanol and ipsenol to Monochamus saltuarius

To develop an optimal attractant for Monochamus saltuarius (Gebler) (Coleoptera: Cerambycidae), the synergistic effects of a few potential attractants (ethanol and α‐pinene as host‐plant volatiles, and ipsenol and ipsdienol as bark beetle pheromones) were tested in a pine forest combined with 2‐(1‐undecyloxy)‐1‐ethanol (monochamol), the aggregation pheromone of Monochamus species, for two consecutive years, 2014 and 2015. Total number of catches was 65 and 33 in 2014 and 2015, respectively. Ethanol or ethanol + monochamol (a base blend) were not attractive to M. saltuarius with no difference from the control. Addition of α‐pinene and ipsdienol to the base blend did not significantly increase catches. However, ipsenol was significantly synergistic to the base blend in attracting M. saltuarius in 2014, and the blend (ipsenol + base blend) attracted meaningfully higher numbers of M. saltuarius in 2015. Our study illustrates the potential for monochamol and ipsenol baits for monitoring and trapping of M. saltuarius in the field.     

Combining pheromone and kairomones for effective trapping of the pine sawyer beetle Monochamus galloprovincialis

Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae) is a secondary wood borer that acquired primordial importance since it was identified as the European vector of Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD). An effective trapping method is needed as a tool for managing this insect vector and allowing early detection of nematode transportation. Among effective attractants identified in recent years are the specific M. galloprovincialis aggregation pheromone, host pine kairomones such as α‐pinene and bark beetle kairomones like ipsenol and methyl‐butenol. The main objective of this study was to optimize the combination of these volatiles to improve lure attractiveness and specificity. Based on ten complementary field experiments, we found a pheromone dose‐response of trap catches. The best combination of attractants was the aggregation pheromone plus two bark beetle kairomones, ipsenol and methyl‐butenol. Addition of pine terpenes, such as α‐pinene, did not significantly improve M. galloprovincialis trap capture, but did increase catch of non target species, including natural enemies. The use of pine terpenes would be advisable only if priorizing to maximize removal of vectors. While this research has lead to the development a new, highly attractive commercial lure for mature pine sawyers, none of the tested blends were successful in attracting immature pine sawyer adults. Further investigation is needed to develop attractants for these beetles.     

2‐(Undecyloxy)‐ethanol is a major component of the male‐produced aggregation pheromone of Monochamus sutor

The small white‐marmorated longicorn beetle, Monochamus sutor (L.) (Coleoptera: Cerambycidae), is widely distributed throughout Europe and Asia. It is a potential vector of the pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, the causal agent of the devastating pine wilt disease. Volatiles were collected from both male and female beetles after maturation feeding. In analyses of these collections using gas chromatography (GC) coupled to mass spectrometry, a single male‐specific compound was detected and identified as 2‐(undecyloxy)‐ethanol. In analyses by GC coupled to electroantennography the only consistent responses from both female and male antennae were to this compound. Trapping tests were carried out in Spain, Sweden, and China. 2‐(Undecyloxy)‐ethanol was attractive to both male and female M. sutor beetles. A blend of the bark beetle pheromones ipsenol, ipsdienol, and 2‐methyl‐3‐buten‐2‐ol was also attractive to both sexes in Spain and Sweden, and further increased the attractiveness of the 2‐(undecyloxy)‐ethanol. The host plant volatiles α‐pinene, 3‐carene, and ethanol were weakly attractive, if at all, in all three countries and did not significantly increase the attractiveness of the blend of 2‐(undecyloxy)‐ethanol and bark beetle pheromones. 2‐(Undecyloxy)‐ethanol is thus proposed to be the major, if not only, component of the male‐produced aggregation pheromone of M. sutor, and its role is discussed. This compound has been reported as a pheromone of several other Monochamus species and is another example of the parsimony that seems to exist among the pheromones of many of the Cerambycidae. Traps baited with 2‐(undecyloxy)‐ethanol and bark beetle pheromones should be useful for monitoring and control of pine wilt disease, should M. sutor be proven to be a vector of the nematode.     

Evaluation of attractants and traps for monitoring small banded pine weevil Pissodes castaneus

This study aimed to develop a semiochemical‐baited trapping system to monitor the populations of small banded pine weevil, Pissodes castaneus, a serious pest in Pinus sylvestris young stands that are weakened by biotic and abiotic factors. The scope of the work included the development of a dispenser for compounds (ethanol and α‐pinene) emitted by P. sylvestris and the pheromones of P. castaneus: grandisol and grandisal. Additionally, the effectiveness of beetle catches in different types of traps (unitrap, cross‐unitrap and long and short pipe traps) baited with a dispenser was assessed. The olfactometric studies showed that most of the newly hatched beetles that had not fed were attracted by a mixture of grandisol and grandisal. However, in the group of feeding beetles, half were attracted by a mixture of ethanol and α‐pinene. These results indicated that both pheromones and α‐pinene plus ethanol should be useful for capturing P. castaneus beetles. In the field trials, the highest efficiency was found in baited unitraps that caught up to several hundred P. castaneus beetles, while the baited cross‐unitraps caught up to a few dozen beetles. No insects were found in either type of baited pipe trap or in any of the unbaited control traps. The baited unitraps and cross‐unitraps also collected, with varied intensity, Hylobius abietis beetles, a serious pest of reforestations. These results indicate the possibility of using a unitrap baited with a 4‐component attractant for monitoring P. castaneus in integrated pest management for the protection of young forests.     

Trapping strategy for Monochamus sutor and Monochamus galloprovincialis: potential vectors of the pine wood nematode in Scandinavia

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Evaluation of traps of six different designs to capture pine sawyer beetles (Coleoptera: Cerambycidae)

1 Sawyer beetles (Coleoptera: Cerambycidae) and metallic wood‐boring beetles (Coleoptera: Buprestidae) attack recently killed or felled trees. They are attracted to potential hosts by volatiles and possibly by visual cues. We examined traps of six different designs to determine the role of silhouette and shape in the capture of pine sawyer beetles, Monochamus L. 2 Traps with a round black cylinder, a single vane (clear or black), or cross vanes (clear or black) all mounted above a pan were compared to an open pan. Each pan contained soapy water to retain insects. 3 Traps with a black silhouette were significantly more effective in capturing male and female Monochamus scutellatus (Say) than traps with or without clear vanes. For both sexes of M. mutator LeConte, pan traps were as effective as traps with a black silhouette. Silhouette was not important for the capture of male and female M. notatus (Drury). Trap catches for the six trap types were not significantly different for male Buprestis maculativentris Say. 4 A pan trap with a black silhouette is recommended for general use in capturing wood‐boring cerambycids and buprestids.     

Comparison of volatile organic compounds from uninfested and Monochamus alternatus Hope infested Pinus massoniana Lamb.

Monochamus alternatus is a destructive stem‐boring herbivore of Pinus massoniana, and the principal vector of pine wood nematode. To investigate the impacts of boring by M. alternatus larvae on the emission of volatile organic compounds (VOCs) from their host trees, the VOCs from uninfested and M. alternatus larvae infested P. massoniana trees were observed using a gas chromatograph–mass spectrometer. We detected 12, 9, 18 and 14 volatile organic compounds from infested xylem, infested phloem, uninfested xylem and uninfested phloem, respectively. In P. massoniana xylem, the boring of M. alternatus larvae induced cyclosativene, and inhibited 4‐carene, humulene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene and γ‐terpinene. The relative amounts of camphene, copacamphene, longicyclene, longifolene, tricyclene and α‐longipinene were significantly increased, and the relative amounts of α‐pinene and β‐pinene were significantly decreased by the boring behaviors of M. alternatus larvae. In P. massoniana phloem, the boring of M. alternatus larvae induced 2‐bornanone, copacamphene, longicyclene and α‐longipinene, and inhibited 2‐carene, 4‐carene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene, β‐pinene, γ‐terpinene and ο‐cymene. The relative amounts of camphene, caryophyllene and longifolene were significantly increased by the boring behaviors of M. alternatus larvae. The results indicate that the boring behaviors of M. alternatus larvae changed both the sorts and contents of the VOCs from P. massoniana trees.     

Changes in spatial and temporal distributions of Monochamus beetles along the fire severity in burned Pinus densiflora forests

Wildfire is an important disturbance factor in forest ecosystem and could affect the distribution of insects. Because Monochamus beetles are known vector insects of pine wood nematodes in Korea and burnt pine trees can be used as oviposition habitats for Monochamus beetles, we investigated changes in the spatial (among fire severity classes) and temporal (between years) distributions of M. alternatus and M. saltuarius. From late May 2017 to early October 2018, four multi-funnel traps with pheromone lure were installed in each fire severity class (unburned, light, light-moderate edge, moderate-severe edge, and severe). All traps were replaced fortnightly from May to October for two years. The spatial distribution of the two Monochamus beetles was significantly affected by fire severity. In particular, M. alternatus showed higher catches in the severely burned sites and responded positively to the fire. A similar number of M. saltuarius individuals were observed between 2017 and 2018, while more M. alternatus were caught in 2018 compared to 2017. Consequently, it was confirmed that the dead wood of P. densiflora caused by the wildfire had a great influence on the density of insects, especially M. alternatus.     

Synergistic effects of α-pinene and exo-brevicomin on pine bark beetles and associated insects in Arizona

The southern pine beetle (Dendroctonus frontalis) and western pine beetle (Dendroctonus brevicomis) cause significant mortality to pines in the southern and western United States. The effectiveness of commercial lures at capturing these bark beetles in Arizona has not been tested and may vary from other regions of their distribution. We conducted experiments using baited Lindgren funnel traps to investigate (i) if D. frontalis is more attracted to the standard commercial lure for D. brevicomis (frontalin + exo‐brevicomin + myrcene) than the D. frontalis lure (frontalin + terpene blend), (ii) whether replacement of myrcene with α‐pinene changes trap catches of Dendroctonus and associated insects, and (iii) whether the attraction to these lures varies across the geographical range of ponderosa pine forests throughout Arizona. In 2005, we tested various combinations of frontalin, exo‐brevicomin, myrcene and α‐pinene to D. frontalis, D. brevicomis and associated species. Dendroctonus frontalis, D. brevicomis and the predator Temnochila chlorodia were most attracted to lures with exo‐brevicomin. The replacement of the myrcene component with α‐pinene in the D. brevicomis lure resulted in the capture of twice as many bark beetles and Elacatis beetles. However, T. chlorodia did not differentiate between monoterpenes. In 2006, traps were set up in 11 locations around Arizona to test the relative attraction of lure combinations. In 9 out 11 locations, the D. brevicomis lure with α‐pinene was more attractive than the lure with myrcene or a terpene blend. These results suggest that the D. brevicomis lure with α‐pinene rather than myrcene is more effective lure to capture D. brevicomis and D. frontalis in Arizona. However, geographical variation in attractiveness to lures is evident even within this region of the beetles’ distributions. Differential attraction of Dendroctonus and their predators to these lures suggests potential use in field trapping and control programmes.     

Selective manipulation of predators using pheromones: responses to frontalin and ipsdienol pheromone components of bark beetles in the Great Lakes region

Abstract 1 One proposed approach to improving biological control of bark beetles (Coleoptera: Scolytidae; alt. Curculionidae: Scolytinae) is to manipulate predator movement using semiochemicals. However, selective manipulation is impeded by attraction of both predators and pests to bark beetle pheromones. 2 The primary bark beetle affecting pine plantations in Wisconsin, U.S.A., is the pine engraver, Ips pini (Say). Other herbivores include Ips grandicollis (Eichhoff) and Dryophthorus americanus Bedel (Curculionidae). The predominant predators are the beetles Thanasimus dubius (Cleridae) and Platysoma cylindrica (Histeridae). 3 We conducted field assays using two enantiomeric ratios of ipsdienol, and frontalin plus α‐pinene. Ipsdienol is the principal pheromone component of I. pini, and frontalin is produced by a number of Dendroctonus species. α‐Pinene is a host monoterpene commonly incorporated into commercial frontalin lures. 4 Thanasimus dubius was attracted to frontalin plus α‐pinene, and also to racemic ipsdienol. By contrast, I. pini was attracted to racemic ipsdienol, but showed no attraction to frontalin plus α‐pinene. Platysoma cylindrica was attracted to 97%‐(–)‐ipsdienol and, to a lesser extent, racemic ipsdienol, but not to frontalin plus α‐pinene. Ips grandicollis was attracted to frontalin plus α‐pinene but not to ipsdienol. Dryophthorus americanus was attracted to both ipsdienol and frontalin plus α‐pinene. 5 This ability to selectively attract the predator T. dubius without attracting the principal bark beetle in the system, I. pini, provides new opportunities for research into augmentative biological control and basic population dynamics. Moreover, the attraction of T. dubius, but not P. cylindrica, to frontalin plus α‐pinene creates opportunities for selective manipulation of just one predator. 6 Patterns of attraction by predators and bark beetles to these compounds appear to reflect various degrees of geographical and host tree overlap with several pheromone‐producing species.     

Transmission of Bursaphelenchus xylophilus between Monochamus alternatus and Monochamus saltuarius through interspecific mating behaviour

Cerambycid adults of the genus Monochamus transmit the pine wood nematode (Bursaphelenchus xylophilus [Steiner et Buhrer] Nickle), the causative agent of pine wilt disease. To confirm the transmission of B. xylophilus between vector species, nematode‐infected Monochamus alternatus Hope and nematode‐free Monochamus saltuarius (Gebler) adults were paired and their behaviour was observed for 107–220 min. In three pairs that exhibited mounting without copulation, nematode transmission occurred, whereas it was not found in another pair without mountings. The effect of nematode transmission between different vector species on the invasion biology of B. xylophilus is discussed.     

Development of an improved attractive lure for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae)

Abstract 1 The pine shoot beetle, Tomicus piniperda (L.) (Coleoptera: Scolytidae), is an exotic pest of pine, Pinus spp., and was first discovered in North America in 1992. 2 Although primary attraction to host volatiles has been clearly demonstrated for T. piniperda, the existence and role of secondary attraction to insect‐produced pheromones have been widely debated. 3 Currently, commercial lures for T. piniperda include only the host volatiles α‐pinene in North America and α‐pinene, terpinolene and (+)‐3‐carene in Europe. Several potential pheromone candidates have been identified for T. piniperda. 4 We tested various combinations of host volatiles and pheromone candidates in Michigan, U.S.A., and Ontario, Canada, to determine an optimal blend. 5 Attraction of T. piniperda was significantly increased when trans‐verbenol (95% pure, 3.2%cis‐verbenol content) was added with or without myrtenol to α‐pinene or to blends of α‐pinene and other kairomones and pheromone candidates. 6 Our results, together with other research demonstrating that trans‐verbenol is produced by T. piniperda, support the designation of trans‐verbenol as a pheromone for T. piniperda. A simple operational lure consisting of α‐pinene and trans‐verbenol is recommended for optimal attraction of T. piniperda.     

The effects of α‐pinene on the feeding performance and pheromone production of Dendroctonus valens

Herbivorous insects exploit multiple plant cues to detect and orient toward suitable hosts and, accordingly, hosts have evolved complex constitutive and inducible defenses in response. In China, the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), an invasive bark beetle from North America, attacks mainly Pinus tabuliformis Carrière (Pinaceae), which contains many monoterpenes. In this study, we explored how the monoterpene α‐pinene affects the feeding performance and pheromone production of D. valens. First, the composition and quantities of monoterpenes of both P. tabuliformis healthy trees and fresh stumps were determined and the infestation of D. valens in healthy trees and fresh stumps was investigated, linking the amount of monoterpenes and D. valens infestation. Gas chromatography–mass spectrometry (GC‐MS) analysis showed that P. tabuliformis mainly contained α‐pinene, with concentrations of 0.1 and 0.5 mg g^?1 in healthy pine phloem and stump phloem, respectively. Second, the monoterpene's influence on feeding performance was tested using phloem media with α‐pinene concentrations ranging from 0 to 30 mg g^?1. The results showed that the percentages of beetles boring and the gallery lengths of both adult females and larvae were negatively correlated with the α‐pinene concentration although body weight changes did not correlate with α‐pinene concentration. Finally, pheromone analysis showed that the production of all pheromones increased with increasing α‐pinene concentrations. This study showed the dual effects of α‐pinene on D. valens: α‐pinene inhibited the bark beetle's feeding activities and in turn the bark beetle made use of it to produce pheromones. Our study indicated the importance of promptly removing fresh stumps in the field for the management of the bark beetle.     

Response of the whitespotted sawyer beetle, Monochamus s. scutellatus, and associated woodborers to pheromones of some Ips and Dendroctonus bark beetles

The response of whitespotted sawyer beetle, Monochamus s. scutellatus, to pheromones of the bark beetles, Dendroctonus rufipennis, Ips pini, Ips perturbatus and Ips latidens, and α‐pinene was investigated with field‐trapping experiments. Traps baited with ipsenol caught significantly more M. s. scutellatus than unbaited traps, whereas the other compounds (ipsdienol, ipsdienol plus lanierone, ipsdienol plus cis‐verbenol or frontalin) did not. Combining α‐pinene with ipsdienol, ipsdienol plus lanierone, ipsdienol plus cis‐verbenol or with frontalin did not increase captures of M. s. scutellatus above those of α‐pinene alone, whereas the combination of α‐pinene with ipsenol did. When α‐pinene was combined with ipsdienol or frontalin, trap captures of Monochamus mutator were significantly higher than unbaited traps or traps baited with frontalin but were not higher than traps baited with α‐pinene. The combination of ipsenol and α‐pinene was significantly more attractive to Monochamus notatus than unbaited traps; however, traps containing either ipsenol or α‐pinene were as attractive as the combination. None of the species of Buprestidae (Buprestis maculativentris and Chalcophora virginiensis) responded significantly to any of the treatments.     

Attraction to monoterpenes and beetle‐produced compounds by syntopic Ips and Dendroctonus bark beetles and their predators

• 1 Bark beetles are significant mortality agents of conifers. Four beetle species, the pine engraver Ips pini, the six‐spined pine engraver Ips calligraphus sub. ponderosae, the southern pine beetle Dendroctonus frontalis, and the western pine beetle Dendroctonus brevicomis, cohabitate pines in Arizona.
• 2 A pheromone trapping study in ponderosa forests of Arizona determined the attraction of beetles to conspecific and heterospecific pheromone components in the presence and absence of host volatiles, and tested whether predators differ in their attraction to combinations of pheromone components and tree monoterpenes.
• 3 All four bark beetle species differed in their responses to heterospecific lures and monoterpenes. Ips calligraphus was the only species that increased in trap catches when heterospecific lures were added. Heterospecific lures did not inhibit the attraction of either Dendroctonus or Ips species. The replacement of myrcene with α‐pinene increased the attraction of Dendroctonus, whereas the addition of α‐pinene had mixed results for Ips. The prominent predators Temnochila chlorodia and Enoclerus lecontei were more attracted to the I. pini lure than the D. brevicomis lure, and the combination of the two lures with α‐pinene was most attractive to both predator species.
• 4 Cross attraction and limited inhibition of bark beetles to heterospecific pheromones suggest that some of these species might use heterospecific compounds to increase successful location and colonization of trees. Predator responses to treatments suggest that tree volatiles are used to locate potential prey and predators are more responsive to Ips than to Dendroctonus pheromone components in Arizona.

     

Effects of plant volatiles on electrophysiological and behavioral responses of Cryptorrhynchus lapathi

Electroantennogram (EAG), Y‐tube olfactometer, and wind tunnel bioassays were conducted to test the electrophysiological and behavioral responses of Cryptorrhynchus lapathi L. (Coleoptera: Curculionidae) to six individual volatiles and seven essential oils (compounded volatiles). The aim of this study was to select effective plant compounds that can be used in the development of semiochemical‐based push–pull methods for the control of this harmful insect. Male and female C. lapathi displayed strong EAG responses to linoleic acid, α‐pinene, (Z)‐3‐hexen‐1‐ol, geraniol, turpentine oil, and salicylaldehyde. Y‐tube olfactometer assays indicated that salicylaldehyde and α‐pinene elicited strong repellent effects on female C. lapathi. Linoleic acid and (Z)‐3‐hexen‐1‐ol showed greater luring effects on male and female C. lapathi compared with the control. Turpentine oil was stronger repellent, and geraniol showed stronger luring effects on male C. lapathi than the control. Wind tunnel assays with both male and female C. lapathi indicated that salicylaldehyde, α‐pinene, and turpentine oil elicited repellent effects compared with the control. Linoleic acid, (Z)‐3‐hexen‐1‐ol, and geraniol were stronger lures of both male and female C. lapathi than the control. These results provide a basis for the further development of C. lapathi luring and repellent agents.     

Feeding and oviposition preference of the Sakhalin pine sawyer Monochamus saltuarius (Coleoptera: Cerambycidae) for various tree species

Monochamus saltuarius was recently identified as an important vector of Bursaphelenchus xylophilus, the cause of pine wilt disease. In this study, M. saltuarius adults preferred different species of tree based on the longevity, ingested amount and wounded area that were determined for 90 d. Among eight tree species, the longevity of feeding by M. saltuarius was not significantly different except when feeding in Sciadopitys verticillata. However, the highest ingested amounts with the largest wounded areas were associated with Pinus koraiensis. The highest oviposition preference was in P. densiflora for the first 20 d. However, after 40 d, the oviposition highest preference was noted in P. koraiensis. For oviposition activities, M. saltuarius preferred the tree species in the following order: P. densiflora > P. koraiensis > P. rigida > Larix leptolepis. Although many oviposition scars were observed, M. saltuarius laid fewer eggs in P. rigida than other species of pine, which was related to the bark thickness. The oviposition frequencies were highest with bark 2.0–2.5 mm thick and with tree diameters of 110–130 mm. The current study increased understanding of the ecology of M. saltuarius by identifying specific tree preferences.     

Effect of semiochemicals and trap height on catch of Neocerambyx raddei in Jilin province,China

We conducted experiments in Jilin, China, in 2011 and 2014 in forest stands dominated by mature Quercus mongolica Fisch. ex Ledeb. (Fagaceae) to test the effects of longhorn beetle pheromones, plant volatiles, and trap height on catch of Neocerambyx raddei (Blessig & Solsky) (formerly Massicus raddei) (Coleoptera: Cerambycidae) in traps. Traps captured 276 specimens of N. raddei in 2011 and 379 specimens in 2014 (384 females, 271 males). Ethanol was attractive to female but not male N. raddei. However, N. raddei was not attracted to any of the longhorn beetle pheromones tested, which included racemic 3‐hydroxyhexan‐2‐one, racemic 3‐hydroxyoctan‐2‐one, syn‐2,3‐hexanediols, anti‐2,3‐hexanediols, racemic E,Z‐fuscumol, racemic E,Z‐fuscumol acetate, and monochamol, nor was it attracted to 2‐methyl‐3‐buten‐2‐ol. Traps placed in the tree canopy captured significantly more beetles than did traps in the understorey. Our results suggest that surveys for N. raddei should use ethanol‐baited traps placed in the tree canopy. If sex or aggregation pheromones are identified for N. raddei in the future, we predict that attraction to them will be enhanced by the presence of ethanol.     

Antennal and behavioural responses of the spruce seed moth,Cydia strobilella,to floral volatiles of Norway spruce,Picea abies,and temporal variation in emission of active compounds

We investigated whether spruce seed moth, Cydia strobilella L. (Lepidoptera: Tortricidae, Grapholitini), one of the most damaging seed predators on Norway spruce, Picea abies (L.) H. Karst (Pinaceae), uses olfactory cues during host search. Analyses with coupled gas chromatography and electroantennography revealed that antennae of both sexes of moths responded consistently to three compounds in the headspace from female spruce flowers, i.e., α‐pinene, β‐pinene, and myrcene, but not to limonene as has been previously reported for this species. The amounts of these active volatiles released from flowers and cones of P. abies were quantified, and their diurnal and seasonal variation was monitored. The total release of the active volatiles correlated well with the diurnal and seasonal flight activity of C. strobilella as revealed by catches of males in pheromone‐baited traps. In field trapping experiments, where baits were loaded with proportions and enantiomeric ratios of α‐pinene, β‐pinene, and myrcene matching those of the female P. abies floral headspace, substantial catches of male C. strobilella were achieved, whereas few females were captured. These surprising results suggest that male C. strobilella make use of host volatiles to aid them in their search for females.