Evaluation of semiochemicals potentially synergistic to α-pinene for trapping the larger European pine shoot beetle, Tomicus piniperda (Col., Scolytidae)

Abstract:  The pine shoot beetle, Tomicus piniperda (L.) (Col., Scolytidae) is an exotic pest of pine, Pinus spp., in North America. It is attracted strongly to host volatiles (±)- α -pinene, (+)-3-carene, and α -terpinolene. Attraction to insect-produced compounds is less clear. Other potential attractants include trans -verbenol, myrtenol, myrtenal, nonanal and α -pinene oxide. We conducted a series of field experiments to determine if any of these compounds would increase attraction of T. piniperda to α -pinene, either individually or in various combinations. None of the individual compounds increased attraction. Although several combinations that included trans -verbenol, nonanal, myrtenol, or myrtenal increased attraction, results were variable between experiments.     

Characterization of five microsatellite loci in the pine shoot beetle Tomicus piniperda (Coleoptera: Scolytidae)

Tomicus piniperda is a bark beetle that causes damage to various pine species across a wide geographical range. We developed five microsatellite polymorphic markers using an enrichment protocol. All loci could be successfully amplified with no evidence of null alleles and will be useful for population genetic studies. Cross‐species amplifications show that at least some of the markers could be useful in four other Tomicus species.     

Attack dynamics of the pine shoot beetle, Tomicus piniperda (Col.; Scolytinae) in Scots pine stands defoliated by Bupalus piniaria (Lep.; Geometridae)

Abstract 1 After a 1‐year, extensive pine looper (Bupalus piniaria) outbreak, plots were laid out to study tree susceptibility to attack, and performance of Tomicus piniperda in pine trees suffering from varying levels of defoliation. 2 Tomicus piniperda was the dominating stem‐attacking species among the primary stem colonizers, and 82% of all trees that died had been colonized by T. piniperda. 3 Beetle attacks primarily struck severely defoliated trees, i.e. trees that suffered from 90% to 100% defoliation. 4 Beetle attacks peaked in the second year after cessation of the outbreak, and suppressed trees were both more frequently attacked and more susceptible to beetle attack than intermediate and dominant trees. 5 Trees surviving beetle attacks carried more foliage than trees that did not survive the attacks. 6 A single year of severe defoliation is enough to render pine trees susceptible to secondary pests, such as T. piniperda.     

Kairomonal responses of Tomicus destruens (Col., Scolytidae) to host volatiles α-pinene and ethanol

The Mediterranean pine shoot beetle Tomicus destruens is one of the most damaging bark beetles attacking Mediterranean pine forests in southern Europe and north Africa. We studied the attractiveness of the host volatiles α-pinene and ethanol at a range of release rates, alone or in combination, to T. destruens , in order to develop an attractive lure for the management of this beetle. T. destruens was attracted slightly to the host volatile α-pinene, but a strong synergistic effect was found in the attraction towards monoterpene when ethanol was added to the bait. The highest catches of T. destruens were obtained by the optimal blend releasing 300 mg/day of α-pinene and 900 mg/day of ethanol. In contrast to data reported for the related species T. piniperda , Mediterranean pine shoot beetles were clearly attracted to baits releasing ethanol alone (1350 mg/day). trans -Verbenol, which was also added to host volatiles in some tests, did not affect the response. The use of the attractive blend proposed would have a low impact on the natural enemy population of Thanasimus formicarius because of asynchronies in flight periods. Other non-target insects, such as the facultative predator or competitor Oxipleurus nodieri , were also significantly attracted. These results allow the development of an operative lure for the effective monitoring of T. destruens , although improvements by the addition of other host volatiles should be studied.     

云南横坑切梢小蠹生物学研究

横坑切梢小蠹Tomicus minor (Hartig)是云南松Pinus yunnanensis Franchet的主要次期性害虫之一。1980年以来,该虫与纵坑切梢小蠹T. piniperda（L.）一起在中国西南部大量发生,导致数十万公顷云南松林受害。本文报道了横坑切梢小蠹在云南地区的生活史、生长、发育、繁殖等生物学特征。横坑切梢小蠹年生活史为一代,前后两代在冬春季有部分重叠。成虫羽化于4月下旬开始陆续,5 月下旬结束。成虫羽化后即飞到树冠上蛀食枝梢,直到11月发育成熟,开始繁殖。在此期间,每头成虫可以蛀食4～6个枝梢。横坑切梢小蠹在云南没有越冬习性。繁殖期从11月至次年3月。成虫主要在已经受到纵坑切梢小蠹危害的树木的中、下部产卵。繁殖期较纵坑切梢小蠹约迟1周。由于横坑切梢小蠹从枝梢到树干对云南松持续危害,对树木的危害性较在其它地区更为严重。横坑切梢小蠹利用受到纵坑切梢小蠹蛀害的树木繁殖产卵,加强了蠹虫对云南松树的危害,加速了受害树木的死亡进程。横坑切梢小蠹的上述生物生态学特征是该虫对云南松造成严重危害的重要原因。从横坑切梢小蠹虫体和虫坑中检测到伴生真菌云南半帚孢Leptographium yunnanensis。横坑切梢小蠹对该菌的带菌率在蛀梢期为11.5%;在蛀干中期约为10%～26%。     

Suitability of some southern and western pines as hosts for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae)

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that has become established in North America. Discovered in Ohio in 1992, it has since been found in at least 13 states and parts of Canada. The beetle can cause significant growth loss in pines, and it represents a potential threat to trees in areas where it has not yet become established. To evaluate this threat to native pines, field and laboratory tests were conducted on several common and important southern and western species to determine whether they are acceptable hosts for T. piniperda. Comparisons with Pinus sylvestris L., Scots pine, a preferred natural host for the beetle, were made where possible. Measurements of beetle attack success on southern pine billets showed that Pinus taeda L., Pinus echinata Miller, Pinus elliottii var. elliottii Engelmann, Pinus palustris Miller, and Pinus virginiana Miller (loblolly, shortleaf, slash, longleaf, and Virginia pine, respectively) and two western pines, Pinus ponderosa Lawson and Pinus contorta Douglas (ponderosa and lodgepole pine, respectively), were acceptable for breeding material, but brood production was highly variable. Among the southern pines, P. taeda and P. echinata were susceptible to shoot feeding by T. piniperda, whereas P. elliottii was highly resistant and P. palustris seemed to be virtually immune. Shoot feeding tests on the western pines were conducted only in the laboratory, but there was moderate-to-good survival of adults feeding on both species. It seems that if T. piniperda is introduced into the south and west it will likely establish and may cause some damage to native pines. P. taeda may be affected more than other southern pines because it is the most abundant species, it is readily attacked for brood production, which can result in moderately large broods, and the beetle survives well during maturation feeding on P. taeda shoots.     

光照、温度对纵坑切梢小蠹起飞行为的影响

纵坑切梢小蠹有明显的趋光性。在光照为 1～ 4 0 0 lx范围内 ,趋光性随光照强度提高而增强。完全黑暗条件下 ,蠹虫起飞量极少。在光照 10 0 0 lx,温度 2 5℃下 ,蠹虫起飞率达 77.7%。研究认为 ,温度和光照是纵坑切梢小蠹起飞的重要环境因素     

Feeding behaviour of the black pine beetle,Hylastes ater (Coleoptera: Scolytidae)

1 The feeding behaviour of Hylastes ater was investigated at 15 °C and 20 °C on a range of tree species. The role of an aggregation pheromone and the part played by olfactory cues in food selection was also investigated. 2 A distinct hierarchical preference at both 15 °C and 20 °C such that Pinus radiata > Pinus sylvestris > > Picea abies > > Rubus fruticosus=Betula pendula was shown. 3 Feeding on P. sylvestris led to the highest weight gain, closely followed by P. radiata and P. abies. Slightly elevated feeding was observed at 20 °C compared with 15 °C. 4 Reduced feeding in the presence of B. pendula suggests the possibility of an antifeedant effect and predamaged wood was found to be less nutritious, possibly due to greater plant defences. 5 The role of an aggregation pheromone was not supported. Olfactory cues enabled the detection of woody hosts, although differentiation between host was not observed. 6 These results are likely to be important in helping to design an effective integrated control approach against this pest.     

三种绿叶挥发性物质对云南切梢小蠹寄主定位行为的干扰作用

为了研究环境中非寄主阔叶植物释放出的绿叶挥发性物质（GLVs）对针叶树蛀干害虫云南切梢小蠹Tomicus yunnanesis的影响, 选取了(E)-2-己烯醛、 (E)-2-己烯醇和(Z)-3-己烯醇3种释放量较大的绿叶挥发性物质, 通过室内松梢取食试验测试了单组分及两两混合后对云南切梢小蠹寄主定位行为的干扰作用。结果表明： 源于阔叶植物的3种绿叶挥发性物质及其混合物能够不同程度干扰云南切梢小蠹的寄主定位行为。当虫放入广口瓶12 h后, 3个单组分绿叶挥发性物质处理组［A： (E)-2-己烯醛, P＜0.01; B： (E)-2-己烯醇, P＜0.01; C： (Z)-3-己烯醇, P＜0.01］及2个混合组分［D： (E)-2-己烯醛+(E)-2-己烯醇, P＜0.01）; E： (E)-2-己烯醛+(Z)-3-己烯醇, P＜0.01］中滞留在松梢外部的虫数与对照组相比都有显著性差异, 绿叶挥发性物质的存在显著降低了云南切梢小蠹侵害云南松松梢的概率。但是, 24 h后只有D组（P＜0.01）和E组（P＜0.01）滞留在松梢外部的虫数与对照组相比具有显著性差异, 在48 h后只有D组（P＜0.01）与对照相比仍具有显著性差异。本研究为利用非寄主植物的次生代谢产物防治云南切梢小蠹进行了有益的探索。     

Oviposition and development of the immature stages of Tomicus minor (Coleoptera, Scolytidae)

1 This paper describes the construction process of the brood gallery of Tomicus minor and its total length as well as the length of each arm, the fertile part where the female lays her eggs and also, the infertile part. >2 The presence of the parents during the process and their position in the brood gallery (arms or mating chamber) is studied and how it influences the number of eggs laid. Both the first brood galleries and those burrowed by the repenetrating females were observed. 3 The development and duration of the immature stages of the insect in the 3-year study period, from laying to the emergence of the young beetles from the F₁ generation, were also studied.     

Prolonged development time of the bark beetle predator Thanasimus formicarius (Col.: Cleridae) in relation to its prey species Tomicus piniperda (L.) and Ips typographus (L.) (Col.: Scolytidae)

1 The generation time of the bark beetle predator Thanasimus formicarius (L.) (Col.: Cleridae) was found to be predominantly two years both in the field and in rearing experiments conducted with two of its main prey species, the pine shoot beetle Tomicus piniperda (L.) and the spruce bark beetle Ips typographus (L.) (Col.: Scolytidae). 2 Emergence of T. formicarius adults in the first summer was only observed in one of the two rearing experiments, and these individuals represented only 6% of that generation. 3 All individuals not emerging as adults in the first summer remained as larvae in their pupal chambers until the second summer. Pupae were found starting around mid-June, and adults (in pupal chambers) were found from late July through to the end of August. 4 Newly emerged adults had to feed in order to survive hibernation. 5 The existence of T. formicarius races, specialized on certain bark beetle species and with phenologies matching their hosts, could not be demonstrated. After hibernation there was no difference in feeding activity, timing of egg-laying or proportion of egg-laying females between the T. formicarius adults reared as larvae on T. piniperda (flight period in April) and those reared as larvae on I. typographus (main flight period generally starting in late May or early June) when exposed to a temperature and day-length typical of the early spring conditions prevailing during the flight period of T. piniperda. 6 T. formicarius was parasitized by Enclisis vindex (Tschek) (Hym.: Ichneumonidae) in the pupal chamber. 7 The importance of these findings for the population dynamics of bark beetles is discussed.     

An operative kairomonal lure for managing pine sawyer beetle Monochamus galloprovincialis (Coleoptera: Cerymbycidae)

Abstract:  Monochamus galloprovincialis Olivier (Col., Cerambycidae) is a vector of the pine wood nematode, Bursaphelenchus xylophilus , causing the destructive pine wilt disease. An effective lure for monitoring and/or mass-trapping would be of great interest in the management of this pine sawyer. Males and females of this species show an attractive kairomonal response to blends composed of four pheromone compounds used by Ips spp. bark beetles and two host volatiles from pines. This six-component lure is highly attractive but may to be too complex and costly for practical use as each component is released from a separate lure. The role of each component, ipsdienol, ipsenol, cis -verbenol, methyl butenol, α -pinene and ethanol as attractants for M. galloprovincialis was field tested in Spain to obtain a simpler but equally effective bait. Ipsenol was confirmed as the strongest kairomonal signal to M. galloprovincialis synergizing response to α -pinene by 95 times. The addition of methyl butenol to this blend doubled the number of males and females trapped. On the other hand, neither ipsdienol, cis -verbenol nor ethanol improved the results when incorporated into the above three-component blend. A lure consisting of ipsenol, methyl butenol and α -pinene may be very cost-efficient in operational monitoring or mass trapping of M. galloprovincialis . Three potentially repellent candidates, (−)verbenone, methyl cyclohexenone and trans -conophthorin, were also tested against the attractive three-component bait. trans -Conophthorin significantly reduced male catches of M. galloprovincialis ; methyl cyclohexenone had no effect. Verbenone significantly enhanced the response of females to the attractive combination of α -pinene, ipsenol and methyl butenol.     

Tomicus piniperda (Coleoptera: Scolytidae) initial flight and shoot departure along a north-south gradient

The exotic pine shoot beetle, Tomicus piniperda (L.) (Coleoptera: Scolytidae), established in the north central and northeastern United States (U.S.) and adjacent regions in Canada, is regulated by a federal quarantine that restricts movement of pine material during specific times of the year based on the beetle's life history. Although climatic variation occurs across T. piniperda's range, a single set of dates is used for timing the movement of pine logs. We monitored T. piniperda spring flight, fall shoot departure, and air and internal tree temperatures at three sites along a 300-km north-south gradient in Michigan and Indiana. We also estimated dates for initial spring flight (12 degrees C threshold) and fall shoot departure (0 degrees C threshold) across an 850-km gradient using historical temperature records (1901 to 1999). Average daily temperatures in fall 1997 (8 October to 12 December) and spring 1998 (20 February to 21 April) were 1.8 to 2.4 degrees C colder, respectively, at the northern field site than at the southern field site. Fall shoot departure began at approximately the same time (day 289 to 290) at all three field sites, but complete shoot departure was extended by 3 wk at the southern site (day 336) compared with the northern site (day 317). T. piniperda adults were first captured in funnel traps on calendar day 86 at the northern site and on day 59 at the central and southern field sites. Peak flight occurred at approximately the same time (day 86) at all three sites. Within-shoot temperatures were very similar to air temperatures in the fall and aboveground inside-bark temperatures were similar to air temperatures in the spring. Average predicted dates based on historical temperature records varied by 31 d for initial shoot departure and 84 d for initial spring flight between northern Michigan and southern Indiana. Because considerable variation can occur in T. piniperda behavior across a broad geographic range, dates specified in the U.S. Federal quarantine should be adjusted according to local temperatures.     

Ultrastructure of the mycangium of the southern pine beetle,Dendroctonus frontalis (Coleoptera: Curculionidae,Scolytinae): complex morphology for complex interactions

Yuceer, C, Hsu, C.‐Y., Erbilgin, N and Klepzig, K.D. 2011. Ultrastructure of the mycangium of the southern pine beetle, Dendroctonus frontalis (Coleoptera: Curculionidae, Scolytinae): complex morphology for complex interactions. —Acta Zoologica (Stockholm) 92 : 216–224. The southern pine beetle (SPB) (Dendroctonus frontalis Zimmermann) is the most economically important pest of southern pine forests. Beetles carry fungal cells within specialised cuticular structures, called mycangia. Little is known about the mycangia ultrastructure or function. We used cryo‐fracturing and scanning electron microscopy to examine the ultrastructural features of SPB mycangia and surrounding tissues. Mycangia, one on each side of anterior portion of the prothorax, are terminated on the dorsal side at a ‘mycangial bridge’. This sclerotised mycangial bridge does not appear to provide a passage between the two mycangia, suggesting that each mycangium functions independently. Mycangia are surrounded by abundant tracheoles connecting the structures to the outside via openings within the prothorax. Previously unknown pits overlying the mycangial gland cells were also observed in both the inner wall and anterior fold of prothorax. We hypothesise that these openings and pits may play roles in determining which fungi enter, and grow within, the mycangium.     

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.     

Tomicus piniperda (Coleoptera: Scolytidae) shoot-feeding characteristics and overwintering behavior in Scotch pine Christmas trees

Overwintering behavior of Tomicus piniperda (L.) was studied in a Scotch pine (Pinus sylvestris L.) Christmas tree plantation in Indiana (1992-1994) and a plantation in Michigan (1994). In general, adults feed inside shoots during summer, then move to overwintering sites at the base of trees in autumn. In early autumn, adults were most often found in shoot-feeding tunnels that were still surrounded by green needles, whereas few were in tunnels surrounded by yellow or brown needles. For all years and sites combined, the range in the percentage of recently tunneled shoots that contained live T. piniperda adults decreased from 89 to 96% in mid-October, to 15- 66% in early November, to 2-10% in mid-November, and to 0-2% by late November to early December. In each year, the first subfreezing temperatures in autumn occurred in October, before most adults left the shoots. Of 1,285 T. piniperda-tunneled shoots, one to seven tunnels (mean = 1.6) and zero to three adults were found per infested shoot. Of these 1,285 attacked shoots, 55% of the shoots had one tunnel, 33% had two, 9% had three, 3% had four, and <1% had five to seven tunnels each. When two or more tunnels occurred in a single shoot, adults were most commonly found in the innermost (most basal) tunnel. For the 2,070 tunnels found in the 1,285 shoots, average shoot thickness at the tunnel entrance was 6.0 mm, average distance from the tunnel entrance to the shoot tip was 6.3 cm, and average tunnel length was 2.3 cm. Four Scotch pine Christmas trees were dissected in January 1993. Eighty percent of the tunneled shoots were in the upper quarter of the tree crown and 98% were in the upper half. For the four trees inspected in January, one live adult was found in a shoot and 85 adults were found in the outer bark along the lower trunk from 1 cm below the soil line to 19 cm above the soil line. No overwintering adults were found outside the trunk in the duff or soil near the base of each test tree. Implications of these results are discussed in terms of surveying, timing the cutting of Christmas trees, and cutting height for Christmas trees.     

Oviposition behavior and reproductive success of the cerambycid Acanthocinus aedilis in the presence and absence of the bark beetle Tomicus piniperda

The influence of Tomicus piniperda (L.)(Col.:Scolytidae) attacks on Acanthocinus aedilis (L.)(Col.:Cerambycidae) (1) oviposition behavior, (2) breeding material preference and (3) reproductive success was investigated in caged pine bolts with and without egg galleries of T. piniperda. In addition, A. aedilis oviposition behavior was studied in the field. In the presence of T. piniperda attacks most A. aedilis eggs were laid through the entrance holes of the bark beetle egg galleries. In the absence of bark beetle attacks most A. aedilis eggs were laid at places where the outer bark had been damaged and the phloem was exposed. In cages, A. aedilis preferred to oviposit in bolts with bark beetle attacks. Thus, A. aedilis oviposited in all 17 of bark beetle attacked bolts but in only four of nine bolts without T. piniperda attacks. Neither the number of A. aedilis offspring nor the body size of emerging adults differed significantly between bolts attacked by bark beetles and unattacked bolts. Nor was there any significant relationship between the density of bark beetle egg galleries and the production of A. aedilis offspring.     

Morphological and genetic identification of the three pine pests of the genus Tomicus (Coleoptera, Scolytidae) in Europe

Abstract

• 1 Morphological characters were elaborated and part of the mitochondrial COI gene was sequenced in order to facilitate the determination of the three European pine bark beetles Tomicus piniperda, T. destruens and T. minor. The sequence information also provided the first information on the phylogenetic and phylogeographical relationships of these species.
• 2 Three hair rows were found on the antennal club of T. destruens between the second and third suture. Tomicus piniperda had only one row. Three different hair types were detected on the elytra – two hair types were found on T. piniperda, whereas the third hair type was only detected on the elytra of T. destruens.
• 3 The COI region (445 bp) revealed high sequence divergence among T. destruens, T. piniperda and T. minor. The three species proved to be monophyletic species with 16.98–19.23% sequence divergence. A phylogenetic approach placed T. minor and T. destruens as sister taxa, which contradicts the morphological findings.
• 4 European populations of T. piniperda shared two haplotypes, indicating a homogenous distribution of the genotypes. In the American populations only one of these European haplotypes was found. The Greek, Italian and Spanish T. destruens populations revealed three population‐specific haplotypes, indicating restricted gene flow.
• 5 Species‐specific primers were designed to allow a rapid and definitive determination of the two sibling Tomicus species by PCR.

     

A model for the timing of swarming of Tomicus piniperda (Coleoptera: Scolytidae)

Tomicus piniperda is the first bark beetle to swarm in the spring in Fennoscandia. The intensity of swarming is directly related to air temperature above a certain threshold and reaches 100% asymptotically. While temperature sums above the threshold accumulate, swarming rate slows down. A non-linear model was built on these considerations. The model was calibrated to window trap material from northern Finland, and it was validated against published material mainly from Norway. The threshold temperatures in these materials were 10.8°C and 11.6°C, respectively. The predictions of the model were satisfactory, and the model will be tried as a part of an entire population dynamics model. The possibilities to predict not only timing, but also the frequency of attack are discussed.