Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Dendroctonus valens
(red turpentine beetle)

Toolbox

Datasheet

Dendroctonus valens (red turpentine beetle)

Summary

  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Dendroctonus valens
  • Preferred Common Name
  • red turpentine beetle
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta
  • Summary of Invasiveness
  • D. valens was not a known forest pest in China before the outbreak in Shanxi in 1999. However, its pest status in China is steadily increasing due to the beetle's invasive and destructive nature. The State Fore...

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report

Pictures

Top of page
PictureTitleCaptionCopyright
Dendroctonus valens (red turpentine beetle); adult, lateral view. USA. Museum set-specimen.
TitleAdult, lateral view
CaptionDendroctonus valens (red turpentine beetle); adult, lateral view. USA. Museum set-specimen.
Copyright©Erich G. Vallery/USDA Forest Service-SRS-4552/Bugwood.org - CC BY 3.0 US
Dendroctonus valens (red turpentine beetle); adult, lateral view. USA. Museum set-specimen.
Adult, lateral viewDendroctonus valens (red turpentine beetle); adult, lateral view. USA. Museum set-specimen.©Erich G. Vallery/USDA Forest Service-SRS-4552/Bugwood.org - CC BY 3.0 US
Dendroctonus valens (red turpentine beetle); adult, anterior view of head-capsule. Museum set-specimen.
TitleAdult, anterior view
CaptionDendroctonus valens (red turpentine beetle); adult, anterior view of head-capsule. Museum set-specimen.
Copyright©Erich G. Vallery/USDA Forest Service-SRS-4552/Bugwood.org - CC BY 3.0 US
Dendroctonus valens (red turpentine beetle); adult, anterior view of head-capsule. Museum set-specimen.
Adult, anterior viewDendroctonus valens (red turpentine beetle); adult, anterior view of head-capsule. Museum set-specimen.©Erich G. Vallery/USDA Forest Service-SRS-4552/Bugwood.org - CC BY 3.0 US
Dendroctonus valens (red turpentine beetle); larva, collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
TitleLarva
CaptionDendroctonus valens (red turpentine beetle); larva, collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
Copyright©Donald Owen/California Department of Forestry & Fire Protection/Bugwood.org - CC BY-NC 3.0 US
Dendroctonus valens (red turpentine beetle); larva, collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
LarvaDendroctonus valens (red turpentine beetle); larva, collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.©Donald Owen/California Department of Forestry & Fire Protection/Bugwood.org - CC BY-NC 3.0 US
Dendroctonus valens (red turpentine beetle); diagnostic features at posterior end of larva. Collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
TitleLarva
CaptionDendroctonus valens (red turpentine beetle); diagnostic features at posterior end of larva. Collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
Copyright©Donald Owen/California Department of Forestry & Fire Protection/Bugwood.org - CC BY-NC 3.0 US
Dendroctonus valens (red turpentine beetle); diagnostic features at posterior end of larva. Collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.
LarvaDendroctonus valens (red turpentine beetle); diagnostic features at posterior end of larva. Collected from ponderosa pine (Pinus ponderosa) in Shingletown, California, USA.©Donald Owen/California Department of Forestry & Fire Protection/Bugwood.org - CC BY-NC 3.0 US
Dendroctonus valens (red turpentine beetle); damage symptoms, showing large pitch tubes at the attack sites. Attacks are usually confined to lower 3 feet of the bole. USA.
TitleDamage symptoms
CaptionDendroctonus valens (red turpentine beetle); damage symptoms, showing large pitch tubes at the attack sites. Attacks are usually confined to lower 3 feet of the bole. USA.
Copyright©Kenneth E. Gibson, USDA Forest Service, Bugwood.org - CC BY-NC 3.0 US
Dendroctonus valens (red turpentine beetle); damage symptoms, showing large pitch tubes at the attack sites. Attacks are usually confined to lower 3 feet of the bole. USA.
Damage symptomsDendroctonus valens (red turpentine beetle); damage symptoms, showing large pitch tubes at the attack sites. Attacks are usually confined to lower 3 feet of the bole. USA.©Kenneth E. Gibson, USDA Forest Service, Bugwood.org - CC BY-NC 3.0 US

Identity

Top of page

Preferred Scientific Name

  • Dendroctonus valens Leconte

Preferred Common Name

  • red turpentine beetle

Other Scientific Names

  • Dendroctonus beckeri Thatcher
  • Dendroctonus rhizophagus Thomas & Bright

International Common Names

  • English: beetle, red turpentine
  • French: dendroctone rouge de l'epinette; dendroctone rouge de l'épinette

Local Common Names

  • China: hong zhi da xiao du; qiang da xiao du

EPPO code

  • DENCVA (Dendroctonus valens)

Summary of Invasiveness

Top of page

D. valens was not a known forest pest in China before the outbreak in Shanxi in 1999. However, its pest status in China is steadily increasing due to the beetle's invasive and destructive nature. The State Forestry Administration currently ranks D. valens the second most important forest pest in China and a National Management Project was initiated for the pest in 2000. D. valens continues to spread to new regions near infested areas. In 2001, about 30% of 85,300 ha of Chinese pine forest was infested in eastern Shaanxi with a total of 7% mortality. In 2002, infestation extended into Henan province, but timely response by the State Forestry Administration has decreased D. valens-infested pine stands and mortality overall.

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Coleoptera
  •                         Family: Scolytidae
  •                             Genus: Dendroctonus
  •                                 Species: Dendroctonus valens

Description

Top of page Egg

The eggs are shiny, opaque white, ovoid cylindrical, and about 1 mm long. They are often laid in groups of 10-40 or more, along one side of the gallery away from the area of main beetle activity. The egg masses are covered with compacted frass.

Larva

The larva is grub-like, legless and white, except for a brown head capsule and a small brown area at the hind end. A row of small, pale-brown tubercles become evident along each side of the body as the larva grows. The fully-grown larva can be up to 10-12 mm long.

Pupa

The pupa is white and slightly shorter than the larva. The legs and antennae are held against the body in the pupal or resting stage.

Adult

The adult beetles, which are the largest of the Dendroctonus genus, are typically 6-10 mm long and quite stout, 2.1 times as long as wide. At first, the beetle is called a callow adult and is tan, but it rapidly darkens to a reddish-brown. The frons is moderately convex with three elevations, the upper one just below the end of the epicranial suture and the lower two laterally sited on the median frons. The epistomal process is broad, more than 0.55 times as wide as the distance between the eyes. The arms of the epistomal process are oblique about 20° from horizontal and are prominently and roundly elevated. The surface of the epistomal process is longitudinally and broadly concave. The pronotum is 0.73 times as long as wide, 2.2 times as long as the pronotum. Elytral declivity with all interstriae shining, interstriae 1 not elevated, interstriae 2 neither narrower nor more impressed than interstriae 1 and 3, all declivital interstriae coarsely granulated, granulations distributed sometimes confused and sometimes regularly.

Distribution

Top of page

With the exception of the southern Atlantic Coast and Gulf Coast states, D. valens is common in pine and mixed conifer forests in the continental USA, southern Canada, Mexico and Honduras. The native range of the beetle extends roughly from 15°N to north of 60°N latitude and is concentrated between 30°N and 50°N (Song et al., 2000). The altitudinal range of D. valens in central Mexico is under 3000 m, and in Guatemala is between 1500 and 3000 m (Song et al., 2000).

In China, D. valens is widely distributed in Shanxi province and parts of the adjacent provinces Hebei, Henan and Shaanxi. Heavily attacked forests in Shanxi province are located in the Taihang, Lulang and Zhongtiao Mountains, at 35°12'N to 39°16'N latitude (Zhang et al., 2002). The latitudinal range of D. valens in the Americas corresponds well with that of China's national boundaries and the native pines therein. Extensive areas of pine forests are located on mountains and hills below 3000 m in altitude, so the potential range of D. valens in China is far greater than its current distribution (Song et al., 2000).

D. valens has spread rapidly in China since the first outbreak there in 1999 (Li et al., 2001; Miao et al., 2001). To date, it has been found in 62 counties, eight Forestry Bureaux and many plantations in Shanxi, Shaanxi, Hebei and Henan, and infested over half a million hectares of pine stands.

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

ChinaRestricted distributionIntroducedearly 1980sBritton and Sun, 2002; EPPO, 2014
-BeijingPresentEPPO, 2014
-HebeiRestricted distributionIntroducedearly 1980sBritton and Sun, 2002; EPPO, 2014
-HenanRestricted distributionIntroducedearly 1980sBritton and Sun, 2002; EPPO, 2014
-Nei MengguPresentEPPO, 2014
-ShaanxiWidespreadIntroducedearly 1980sBritton and Sun, 2002; EPPO, 2014
-ShanxiWidespreadIntroducedearly 1980sBritton and Sun, 2002; EPPO, 2014

North America

CanadaRestricted distributionNative Not invasive Rappaport et al., 2001; EPPO, 2014
-AlbertaPresentEPPO, 2014
-British ColumbiaPresentSafranyik et al., 2004; EPPO, 2014
-ManitobaPresentEPPO, 2014
-New BrunswickPresentEPPO, 2014
-Newfoundland and LabradorPresentEPPO, 2014
-Northwest TerritoriesPresentEPPO, 2014
-Nova ScotiaPresentEPPO, 2014
-OntarioPresentEPPO, 2014
-QuebecPresentEPPO, 2014
MexicoWidespreadNative Not invasive Cibrian-Tovar et al., 1995; Tovar et al., 1995; EPPO, 2014
USAWidespreadNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-ArizonaPresentEPPO, 2014
-CaliforniaWidespreadNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-ColoradoRestricted distributionNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-ConnecticutRestricted distributionNative Not invasive Ross and Arnett, 2000
-DelawareRestricted distributionNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-FloridaPresentEPPO, 2014
-GeorgiaPresentEPPO, 2014
-IdahoRestricted distributionNative Invasive Ross and Arnett, 2000; EPPO, 2014
-IllinoisRestricted distributionNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-IndianaRestricted distributionNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-IowaRestricted distributionNative Not invasive Ross and Arnett, 2000
-KansasRestricted distributionNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-KentuckyPresentEPPO, 2014
-MainePresentEPPO, 2014
-MarylandPresentEPPO, 2014
-MassachusettsPresentEPPO, 2014
-MichiganPresentEPPO, 2014
-MinnesotaPresentWingfield, 1983; EPPO, 2014
-MontanaPresentSix and Skov, 2009; EPPO, 2014
-NebraskaPresentEPPO, 2014
-NevadaPresentWalker et al., 2007; EPPO, 2014
-New HampshirePresentEPPO, 2014
-New JerseyPresentEPPO, 2014
-New MexicoPresentLivingston et al., 1983; EPPO, 2014
-New YorkPresentPajares and Lanier, 1990; EPPO, 2014
-North CarolinaPresentEPPO, 2014
-OhioPresentEPPO, 2014
-OklahomaPresentEPPO, 2014
-OregonPresent, few occurrencesNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-PennsylvaniaPresentEPPO, 2014
-Rhode IslandPresentEPPO, 2014
-South CarolinaPresentEPPO, 2014
-South DakotaPresentSchmid and Mata, 1991; EPPO, 2014
-TennesseePresentEPPO, 2014
-TexasPresentEPPO, 2014
-UtahPresentEPPO, 2014
-VermontPresentEPPO, 2014
-VirginiaPresentEPPO, 2014
-WashingtonWidespreadNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-West VirginiaPresentEPPO, 2014
-WisconsinWidespreadNative Not invasive Ross and Arnett, 2000; EPPO, 2014
-WyomingPresentEPPO, 2014

Central America and Caribbean

GuatemalaPresentEPPO, 2014
HondurasPresentEPPO, 2014

Risk of Introduction

Top of page D. valens is currently listed as an internal quarantine pest in China, with the aim of preventing its further spread. Shanxi, Shaanxi, Hebei and Henan provinces are listed as quarantined areas for D. valens.

Habitat List

Top of page
CategoryHabitatPresenceStatus
Littoral
Coastal areas Present, no further details Harmful (pest or invasive)
Terrestrial-managed
Cultivated / agricultural land Present, no further details Harmful (pest or invasive)
Disturbed areas Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Protected agriculture (e.g. glasshouse production) Present, no further details Harmful (pest or invasive)
Rail / roadsides Present, no further details Harmful (pest or invasive)
Urban / peri-urban areas Present, no further details Harmful (pest or invasive)
Terrestrial-natural/semi-natural
Deserts Present, no further details Harmful (pest or invasive)
High altitudes, uplands Present, no further details
Natural forests Present, no further details Harmful (pest or invasive)
Natural grasslands Present, no further details Harmful (pest or invasive)
Riverbanks Present, no further details Harmful (pest or invasive)
Wetlands Present, no further details Harmful (pest or invasive)

Hosts/Species Affected

Top of page D. valens is a common pest of pines in its native range in North and Central America (Eaton and Lara, 1967). Mature ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta) are attacked. It is infrequently found in other conifers. It is considered to be a secondary pest and is often associated with other, more aggressive bark beetle species. Tree mortality and outbreaks attributed to D. valens alone are rare in its native range (Smith, 1971; Cibrian-Tovar et al., 1995). However, D. valens has been reported causing tree mortalities in a thinned, subsoiled plantation of P. ponderosa near Ponderosa, California, USA, and in Mexico (Rappaport et al., 2001).

In China, D. valens is a new exotic invasive pest that attacks Pinus tabuliformis and P. bungeana, especially P. tabuliformis. Occasionally, it has been found in Pinus armandii and Picea meyeri, but damage on these hosts has not been confirmed (Zhang et al., 2002). The potential range of D. valens in China is huge as P. tabuliformis is planted widely across much of the country (Britton and Sun, 2002).

Host Plants and Other Plants Affected

Top of page

Growth Stages

Top of page Post-harvest, Vegetative growing stage

Symptoms

Top of page D. valens mainly attacks the lower trunk and roots of trees. Pitch tubes on the outer surface of bark crevices or on the ground at the base of the tree, and pitch pellets on the ground, indicate attack by the red turpentine beetle.

Resin flowing from the wood, beetle frass and bark borings are mixed in the beetle's gallery and pushed out of the entrance hole. The mixture either adheres to the bark surface, forming a pitch tube, or falls to the ground in pitch pellets of various sizes. The pitch tubes vary in size, texture and colour, depending on the kind of tree and the time of observation. The resin is usually white to yellowish, then becomes dark red or black.

Attacked trees often show a colour change in the needles, from green to yellowish green, then through shades of yellow and sorrel to red, which indicates that the tree is dying.

List of Symptoms/Signs

Top of page
SignLife StagesType
Leaves / abnormal colours
Leaves / abnormal colours
Leaves / frass visible
Leaves / frass visible
Leaves / yellowed or dead
Leaves / yellowed or dead
Roots / internal feeding
Roots / internal feeding
Stems / internal feeding
Stems / internal feeding
Stems / visible frass
Stems / visible frass
Whole plant / discoloration
Whole plant / discoloration
Whole plant / frass visible
Whole plant / frass visible
Whole plant / internal feeding
Whole plant / internal feeding
Whole plant / plant dead; dieback
Whole plant / plant dead; dieback

Biology and Ecology

Top of page D. valens preferentially attacks large, old, weak or injured trees, and freshly cut logs or stumps. The beetle attacks in small numbers, so repeated attacks are necessary to kill a tree. Tree mortality and outbreaks attributed to D. valens alone are rare in its native range (Smith, 1971; Cibrian-Tovar et al., 1995). D. valens is considered to be a secondary pest, and is often associated with more aggressive bark beetle species. Trees weakened by D. valens attack are more susceptible to fatal attack by other beetles.

In North America, D. valens attacks the tree at ground level burrowing into the bole and root collar (Smith, 1971), forming large, reddish-brown pitch tubes. The galleries of the beetle are short, irregular and usually vertical. Large, fan-shaped galleries are formed by larval feeding. The development time for D. valens can be up to 2 years in cold areas.

The life cycle and behaviour of D. valens are similar in North America and China; however, some notable differences exist. Foremost among these is the beetle's ability to colonize, kill and reproduce in mature P. tabuliformis, resulting in outbreaks occurring in China that have no parallel in the native range of the pest.

In China, D. valens extensively colonizes and overwinters in the roots of trees (Britton and Sun, 2002; Wu et al., 2002). This extensive root colonization, combined with the presence of fungal associates in the roots, may explain the beetle's tree-killing success in China (Owen, 2001). Fungi isolated from D. valens include Leptographium terebrantis, L. procerum, Ophiostoma ips and a species of Graphium (Owen et al., 1987; Klepzig et al., 1991). Of the Ophiostoma fungi carried by Dendroctonus spp. attacking ponderosa pine, L. terebrantis was the most virulent (Owen et al., 1987; Parmeter et al., 1989). This fungus has also been associated with decline and/or mortality of a number of other species of Pinus (Highley and Tattar, 1985; Klepzig et al., 1991; Bannwart et al., 1998). Virtually nothing is known about the fungal complex associated with D. valens in China. However, it appears that the strain introduced into China with D. valens is more virulent than the one associated with the pest in North America, which is a cause of concern as the Chinese D. valens could be re-introduced to North America carrying more virulent fungi with it.

Flight distances of D. valens in North America can exceed 16 km (Smith, 1971). In China, flight distances of up to 35 km have been documented (Zhang et al., 2002). In China, D. valens cannot overwinter at any stage in boles at temperatures below -18°C. Mortality of D. valens larvae and adults is very low in roots, indicating that roots are important for the survival of the pest (Miao et al., 2001) and can serve as a source of beetles in the following year (Wu et al., 2002).

In China, D. valens primarily attacks Pinus tabuliformis and P. bungeana, especially P. tabuliformis. As a major reforestation species in China, P. tabuliformis is widely planted across much of the country, including degraded and marginal sites. Such sites can contribute to tree stress and are therefore likely to favour the activity of the pest (Li et al., 2001). Drought conditions were thought to have contributed greatly to an outbreak of D. valens in China in 1999 (Li et al., 2001). In general, mature and overmature P. tabuliformis forests are infested, whereas younger forests are seldom attacked. D. valens-infested pine forests are also endangered by another beetle, Hylastes parallelus (Wu et al., 2002). The interaction between these two beetle species and the role of H. parallelus in D. valens infestation are unknown.

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Heterobasidion annosum Pathogen
Rhizophagus grandis Predator

Notes on Natural Enemies

Top of page Predators of D. valens are rare in China. Dendrocopos major, Thansimus sp., Labidura sp., Paederus sp., Plgadeus sp., Cryptolestes sp., Raphidia sp., Deretaphrus sp. and Formica sp. have been found in limited numbers. Pathogens of D. valens in China include Beauveria sp. and Metarrhizium sp. (Zhang et al., 2002). Adult Tenebrionidae sp. reared in laboratory were found to be potentially lethal to D. valens adults and Beauveria sp. and Metarrhizium sp. killed the larvae, adults and pupae of D. valens (Wu et al., 2002).

Pathway Vectors

Top of page
VectorNotesLong DistanceLocalReferences
Clothing, footwear and possessions Yes
Land vehicles Yes
Soil, sand and gravelSoil Yes

Plant Trade

Top of page
Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Bark eggs; larvae Yes Pest or symptoms usually visible to the naked eye
Roots larvae; pupae Yes
Stems (above ground)/Shoots/Trunks/Branches eggs; larvae; pupae Yes Yes Pest or symptoms usually visible to the naked eye
Plant parts not known to carry the pest in trade/transport
Flowers/Inflorescences/Cones/Calyx
Fruits (inc. pods)
Growing medium accompanying plants
Seedlings/Micropropagated plants
True seeds (inc. grain)
Wood

Wood Packaging

Top of page
Wood Packaging liable to carry the pest in trade/transportTimber typeUsed as packing
Solid wood packing material with bark Pinus ponderosa; P. ayacahuite; P. arizonica; P. douglasiana; P. engelmannii; P. gregii; P. hartwegii; P. herrerai; P. jeffreyi; P. lassoni; P. leiphylla; P. maximinoi; P. michoacana; P. pseudostrobus; P. oocarpa; P. tecote; P. tabulaeformis; P. bungeana; P. armandi Yes
Solid wood packing material without bark Ibid Yes

Impact Summary

Top of page
CategoryImpact
Animal/plant collections None
Animal/plant collections None
Animal/plant products None
Animal/plant products None
Biodiversity (generally) None
Biodiversity (generally) None
Crop production None
Crop production None
Environment (generally) None
Environment (generally) None
Fisheries / aquaculture None
Fisheries / aquaculture None
Forestry production None
Forestry production None
Human health None
Human health None
Livestock production None
Livestock production None
Native fauna None
Native fauna None
Native flora None
Native flora None
Rare/protected species None
Rare/protected species None
Tourism None
Tourism None
Trade/international relations None
Trade/international relations None
Transport/travel None
Transport/travel None

Impact

Top of page D. valens is considered to be a secondary pest and is often associated with other, more aggressive bark beetle species. Tree mortality and outbreaks attributed to D. valens alone are rare in its native range (Smith, 1971; Cibrian-Tovar et al., 1995). However, D. valens has been reported causing tree mortalities in a thinned, subsoiled plantation of P. ponderosa near Ponderosa, California, USA, and in Mexico (Rappaport et al., 2001).

Since the first outbreak of D. valens in northern China in 1999, this exotic invasive pest has spread rapidly from Shanxi province to three adjacent provinces (Hebei, Henan and Shaanxi) and infested over half of a million hectares of pine forest, causing extensive mortality. More than 6 million Pinus tabuliformis trees have been killed, as well as other species of pine including Pinus bungeana (Li et al., 2001; Miao et al., 2001). D. valens was introduced to China in the early 1980s when unprocessed logs were imported from the west coast of the USA (Chinese Academy of Sciences, Beijing, China, unpublished report). Several consecutive years of drought conditions stressed the primary host (P. tabuliformis) and contributed greatly to the outbreak in 1999 (Li et al., 2001). As pines are a major reforestation species in China, and P. tabuliformis is widely planted across a large portion of the country, the potential range of, and damage by, this invasive bark beetle is overwhelming (Britton and Sun, 2002).

Economic Impact

Top of page D. valens is considered to be a secondary pest and is often associated with other, more aggressive bark beetle species. Tree mortality and outbreaks attributed to D. valens alone are rare in its native range (Smith, 1971; Cibrian-Tovar et al., 1995). However, D. valens has been reported causing tree mortalities in a thinned, subsoiled plantation of P. ponderosa near Ponderosa, California, USA, and in Mexico (Rappaport et al., 2001).

Since the first outbreak of D. valens in northern China in 1999, this exotic invasive pest has spread rapidly from Shanxi province to three adjacent provinces (Hebei, Henan and Shaanxi) and infested over half of a million hectares of pine forest, causing extensive mortality. More than 6 million Pinus tabuliformis trees have been killed, as well as other species of pine including Pinus bungeana (Li et al., 2001; Miao et al., 2001). D. valens was introduced to China in the early 1980s when unprocessed logs were imported from the west coast of the USA (Chinese Academy of Sciences, Beijing, China, unpublished report). Several consecutive years of drought conditions stressed the primary host (P. tabuliformis) and contributed greatly to the outbreak in 1999 (Li et al., 2001). As pines are a major reforestation species in China, and P. tabuliformis is widely planted across a large portion of the country, the potential range of, and damage by, this invasive bark beetle is overwhelming (Britton and Sun, 2002).

Environmental Impact

Top of page The potential environmental impact of D. valens in China is huge. The beetle has become a primary pine killer in most of its distribution range and, when coupled with drought, can cause ecological disaster in some areas, especially where regeneration is not feasible economically and ecologically. Pinus tabuliformis, the primary host of D. valens in China, is widely planted across the country, so the potential range of the pest is great, and the potential ecological impact of the beetle is unthinkable if further spread cannot be contained or managed effectively. D. valens was ranked the second most important forest pest in China in a National Control Project initiated by the State Forestry Administration in 2000.

Detection and Inspection

Top of page The response of introduced D. valens to host semiochemicals in Shanxi, China, was distinctly different from that reported in studies conducted in the western part of the pests's native range in the central Sierra Nevada, California, USA, suggesting that there may be regional variation in response to host volatiles. In the Chinese population of D. valens, 3-carene was the most attractive host monoterpene tested in studies using multiple funnel traps suspended in a Pinus tabuliformis stand. It attracted significantly more beetles than any other single semiochemical or any of the ternary or quaternary blends tested, including the standard D. valens lure used in North America (a 1:1:1 blend of (+)-a-pinene, (-)-ß-pinene and (+)-3-carene). (+)-a-pinene and (-)-ß-pinene, presented individually, were not significantly more attractive than controls. Adding limonene to the standard lure decreased the response of D. valens, but not significantly. A new type of semiochemical release vial was tested using a range of release rates of a 1:1:1 blend of (+)-a-pine, (-)-ß-pinene and (+)-3-carene. The rates ranged from 150 to 210 mg/day, and these were compared with the standard North American lure, which releases ca 110 mg/day. The most attractive of these vials, which released ca 150 mg/day, captured significantly more beetles than the standard release device, but increasing the release rate beyond 150 mg/day did not further increase the trap catch.

These results provide a new, more effective, single-component lure for use in monitoring and trapping of D. valens in China. This lure is being tested in other parts of the range of D. valens, partly to maximize trapping efficacy in North America and partly to determine the original source(s) of introduction of D. valens from North America to Asia. Such knowledge is often helpful in optimizing biological control and semiochemical control programmes, because they incorporate factors that may vary regionally within a species. It is useful to know that D. valens responds most strongly to 3-carene as an attractant because of the expense of pheromone-grade monoterpenes. The knowledge that the single component lure is three times as effective as the ternary blend will result in considerable savings in large-scale programmes, such as that planned for China in 2002-2004 (Sun et al., 2004).

Prevention and Control

Top of page

Monitoring and Prevention

As D. valens is a new exotic invasive beetle in China, effective monitoring is key to effective management. There is an immediate need to slow down or prevent the spread of the beetle in China. Artificial spread is an important means of dispersal in areas where pine stands are widely separated. Restrictions on unauthorized tree harvesting and the movement of infested material must be strictly enforced. Any pine material with intact bark could potentially harbour the red turpentine beetle. Strict quarantine measures must be enforced at ports, along roads, railways and the boundaries of infested areas. Harvesting green trees creates a breeding habitat for D. valens in stumps, potentially initiating or aggravating outbreaks, and harvesting dying, infested trees may facilitate the spread of the beetle.

Long-term solutions must address tree and stand susceptibility to D. valens. Historical records and protected natural areas can, to a certain extent, serve as models for stand rehabilitation, with D. valens considered a significant input into ecological processes. Stand susceptibility is likely to be a driving force behind the management of affected forests for many years to come. A better understanding of the interaction between D. valens and forest stand attributes will enable managers to devise silvicultural treatments that will produce stands more resistant to beetle attack. It is important to recognize that other insect pests and diseases can affect tree susceptibility to D. valens and that the desired stand condition and health will depend upon the response of all potential pests to treatment.

The inherent susceptibility of P. tabuliformis and other Chinese species of Pinus to attack by D. valens requires further investigation. Reforestation efforts could benefit from the use of resistant genotypes and resistant species mixes. The role of fungi in the success of D. valens needs to be determined, including identification of the fungi carried by the beetle in China. It is important to know whether any variability exists among individual trees or between tree species in response to fungal inoculation and, if so, whether this correlates with the success of the pest.

Chemical Control

Fumigation of boles with phosphine under plastic cover, and spraying insecticides (such as cypermethrin, phoxim) onto boles during the flight period are all effective in killing beetles (90-98% mortality) (Shanxi Forestry Bureau, China, unpublished data). However, fumigation is difficult and costly to apply. It has never been proved to be effective in controlling beetle populations over large areas, and can cause environmental contamination and reduce natural enemy populations.

Cultural Control

Manual control, such as felling and digging out dying or recently dead trees and eliminating any exposed roots and stumps, can be used to eliminate beetles but is too labour-intensive for practical management of the pest.

Trapping

The use of semiochemicals to manipulate beetle populations is a promising management tool for D. valens. The use of lure traps with semiochemicals (host volatiles) is a labour-saving and environmentally friendly method that can be used in all seasons of D. valens activity throughout the year. It attracts both male and female beetles, and studies have shown its effectiveness in reducing tree mortality. Mass-trapping programmes have been used over a 2-year period in China with satisfactory results (Sun et al., 2004).

Biological Control

It is not known to what degree natural enemies regulate D. valens populations in its native range and in China. The introduction of exotic natural enemies to China must be carried out with adequate safeguards to prevent unwanted impacts on native fauna and flora. Sub-cortical insects are known to vector a wide range of organisms that could accidentally be introduced with unknown consequences (Owen, 2001). However, the introduction and establishment of exotic natural enemies could potentially provide long-term regulation of D. valens populations and reduce the need for other treatments.

Integrated Pest Management

A combination of chemical and manual control, and the use of semiochemicals decreased the area of Shanxi province infested by D. valens from 255,720 ha in 1999 to 178,000 ha in 2002.

References

Top of page

Bannwart DL; Otrosina WJ; Roncadori RW, 1998. Blue-stain fungi associated with decline of longleaf pine (Abstr.). Phytopathology, 88(9 Suppl.):S5.

Bennett DC; Freeling M, 1987. Flooding and the anaerobic stress response. In: Newman DW, Wilson KG, eds. Models in Plant Physiology and Biochemistry. Vol. III. Boca Raton, Florida USA: CRC Press, 79-84.

Berryman AA, 1976. Theoretical explanation of mountain pine beetle dynamics in lodgepole pine forests. Environmental Entomology, 5(6):1225-1233

Bright DE, 1976. The insects and arachnids of Canada, Part 2. The bark beetles of Canada and Alaska. Ottawa, Canada: Information Canada, Canada Department of Agriculture Publication Number 1576.

Britton KO; Sun JiangHua, 2002. Unwelcome guests: exotic forest pests. Acta Entomologica Sinica, 45(1):121-130; 24 ref.

Byers JA, 1992. Attraction of bark beetles, Tomicus piniperda, Hylurgops palliatus, and Trypodendron domesticum and other insects to short-chain alcohols and monoterpenes. Journal of Chemical Ecology, 18(12):2385-2402

Chenier JVR; Philogene BJR, 1989. Field responses of certain forest Coleoptera to conifer monoterpenes and ethanol. Journal of Chemical Ecology, 15(6):1729-1745

Cibrian-Tovar D; Mendez-Montiel JT; Campos Bolans R; Yates HO III; Flores Lara J; eds, 1995. Forest Insects of Mexico. [Insectos Forestales de Mexico.] Chapingo, Mexico: Universidad Autonoma Chapingo, 453 pp.

Cobb FW Jr; Zavarin E; Bergot J, 1972. Effect of air pollution on the volatile oil from leaves of Pinus ponderosa. Phytochemistry, 11(5):1815-1818; ORS; 9 ref.

Davies DD, 1980. Anaerobic metabolism and the production of organic acids. In: Davies DD, eds. The Biochemistry of Plant. Vol. 2. Metabolism and Respiration. New York, USA: Academic Press, 581-611.

Drew J; Pylant GD Jr, 1966. Turpentine from the pulpwood of the United States and Canada. Tappi, 49:430-438.

Eaton B; Lara RR, 1967. Red turpentine beetle, Dendroctonus valens LeConte. In: Davidson AG, Prentice RM, eds. Important Forest Insects and Diseases of Mutual Concern to Canada, The United States and Mexico. Ottawa, Canada: Canadian Department of Forestry and Rural Development, 21-24.

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

Erbilgin N; Raffa KF, 2000. Opposing effects of host monoterpenes on responses by two sympatric species of bark beetles to their aggregation pheromones. Journal of Chemical Ecology, 26(11):2527-2548; Many ref.

Erbilgin N; Szele A; Klepzig KD; Raffa KF, 2001. Trap type, chirality of -pinene, and geographic region affect sampling efficiency of root and lower stem insects in pine. Journal of Economic Entomology, 94(5):1113-1121.

Furniss RL; Carolin VM, 1977. Western forest insects. USDA Miscellaneous Publication, No. 1339. Washington DC., USA; US Department of Agriculture.

Fäldt J, 2000. Volatile constituents in conifers and conifer-related wood-decaying fungi: Biotic influences on the monoterpene compositions in pines. ISSN 1100-7974. ISBN 91-7170-608-9 Stockholm.

Gao BJ; Li DY; Cai WP; Yu FC, 1999. Community characteristics of degraded Chinese pine stands and their biodiversity restoration. Acta Ecologica Sinica, 19(5):647-653.

Gara RI; Vite JP, 1962. Studies on the flight patterns of bark beetles (Coleoptera: Scolytidae) in second growth Ponderosa Pine forests. Contr. Boyce Thompson Inst. 21 (5), (275-89). 18 refs.

Gibbs JN; Wainhouse D, 1986. Spread of forest pests and pathogens in the northern hemisphere. Forestry, 59(2):141-153

Hall RW, 1983. Attraction of Dendroctonus valens (Coleoptera: Scolytidae) to ponderosa pines baited with Dendroctonus brevicomis (Coleoptera: Scolytidae) pheromone. Environmental Entomology, 12(3):718-719

Harry DE; Kimmerer TW, Neale DB (ed. ), Kinlaw CS, 1991. Molecular genetics and physiology of alcohol dehydrogenase in woody plants. Forest biotechnology. Forest-Ecology-and-Management, 43(3-4):251-272; 6 pp. of ref.

Hayes JL; Strom BL, 1994. 4-Allylanisole as an inhibitor of bark beetle (Coleoptera: Scolytidae) aggregation. Journal of Economic Entomology, 87(6):1586-1594

Highley L; Tattar TA, 1985. Leptographium terebrantis and black turpentine beetles associated with blue stain and mortality of black and Scots pines on Cape Cod, Massachusetts. Plant Disease, 69(6):528-530

Hobson KR, 1995. Host compounds as semiochemicals for bark beetles. In: Salom SM, Hobson KR, eds. Proceedings of the Symposium on Applications of Semiochemicals for Management of Bark Beetle Infestations. USDA Forest Service General Technical Report INT-GRT-318, 48-51.

Hobson KR; Wood DL; Cool LG; White PR; Ohtsuka T; Kubo I; Zavarin E, 1993. Chiral specificity in responses by the bark beetle Dendroctonus valens to host kairomones. Journal of Chemical Ecology, 19(9):1837-1846

Joseph G; Kelsey RG, 1997. Ethanol synthesis and water relations of flooded Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) seedlings under controlled conditions. International Journal of Plant Sciences, 158(6):844-850; 45 ref.

Joseph G; Kelsey RG; Peck RW; Niwa CG, 2001. Response of some scolytids and their predators to ethanol and 4-allylanisole in pine forests of Central Oregon. Journal of Chemical Ecology, 27(4):697-715; 60 ref.

Kelsey RG, 1994. Ethanol and ambrosia beetles in Douglas fir logs with and without branches. Journal of Chemical Ecology, 20(12):3307-3319

Kelsey RG, 1994. Ethanol synthesis in Douglas-fir logs felled in November, January, and March and its relationship to ambrosia beetle attack. Canadian Journal of Forest Research, 24(10):2096-2104

Kelsey RG; Joseph G, 1999. Ethanol and ambrosia beetles in Douglas fir logs exposed or protected from rain. Journal of Chemical Ecology, 25(12):2793-2809; many ref.

Kelsey RG; Joseph G, 1999. Ethanol and water in Pseudotsuga menziesii and Pinus ponderosa stumps. Journal of Chemical Ecology, 25(12):2779-2792; 34 ref.

Kelsey RG; Joseph G; Thies WG, 1998. Sapwood and crown symptoms in ponderosa pine infected with black-stain and annosum root disease. Forest Ecology and Management, 111(2/3):181-191; 2 pp. of ref.

Klepzig KD; Raffa KF; Smalley EB, 1991. Association of an insect-fungal complex with red pine decline in Wisconsin. Forest Science, 37(4):1119-1139

Klimetzek D; Köhler J; Vité JP; Kohnle U, 1986. Dosage response to ethanol mediates host selection by 'secondary' bark beetles. Naturwissenschaften, 73:270-272.

Kozlowski TT, 1969. Tree physiology and forest pests. J. For. 67 (2), (118-23). [59 refs.].

Krokene P; Solheim H, 1998. Pathogenicity of four blue-stain fungi associated with aggressive and non aggressive bark beetles. Phytopathology, 88(1):39-44; 54 ref.

Le Maitre DC, 1998. Pines in cultivation: a global view. In: Richardson DM, ed. Ecology and Biogeography of Pinus. Cambridge, UK: Cambridge University Press, 407-431.

Li JL; Bai YH; Hu JX; Shao M; Zhang BX; Xie Y; Tang XY, 1994. Diurnal variation in the concentration of terpenes and its emission rate measurements from oil pine. China Environmental Science, 14(3):165-169 (in Chinese).

Li JS; Chang GB; Song YS; Wang YW; Chang BS, 2001. Control Project on Red Turpentine Beetle (Dendroctonus valens). Forest Pest and Disease, 4(3):41-44 (in Chinese).

Li TC; Hou DY; Zhang WH, 2000. Analysis of volatile constituents in young twigs of Pinus tabulaeformis. Chemistry and industry of forest products, 20(4):73-76 (in Chinese).

Liu YB; McLean JA, 1989. Field evaluation of responses of Gnathotrichus sulcatus and G. retusus (Coleoptera: Scolytidae) to semiochemicals. Journal of Economic Entomology, 82(6):1687-1690

Livingston WH; Mangini AC; Kinzer HG; Mielke ME, 1983. Association of root diseases and bark beetles (Coleoptera: Scolytidae) with Pinus ponderosa in New Mexico. Plant Disease, 67(6):674-676

Miao ZW; Chou WM; Huo FY; Wang XL; Fang JX; Zhao MM, 2001. Biology of Dendroctonus valens in Shanxi Province. Shanxi Forestry Science and Technology, 23(1):34-37 (in Chinese).

Mitchell RG; Waring RH; Pitman GB, 1983. Thinning lodgepole pine increases tree vigor and resistance to mountain pine beetle. Forest Science, 29(1):204-211

Moeck HA, 1970. Ethanol as the primary attractant for the ambrosia beetle, Trypodendron lineatum (Coleoptera: Scolytidae). Canad. Ent. 102 (8), (985-95). [34 refs.].

Nebeker TE; Schmitz RF; Tisdale RA; Hobson KR, 1995. Chemical and nutritional status of dwarf mistletoe, armillaria root rot, and comandra blister rust infected trees which may influence tree susceptibility to bark beetle attack. Canadian Journal of Botany, 73(3):360-369

Nordlander G; Eidmann HH; Jacobsson U; Nordenhem H; Sjodin K, 1986. Orientation of the pine weevil Hylobius abietis to underground sources of host volatiles. Entomologia Experimentalis et Applicata, 41(1):91-100

Owen DR, 1985. The role of Dendroctonus valens and its vectored fungi in the mortality of ponderosa pine. PhD Dissertation. University of California, Berkeley.

Owen DR, 2001. Consultation on the red turpentine beetle, Dendroctonus valens, in Shanxi Province, PR China, July 1-7, 2001. Report prepared for USDA Forest Service International Programs. USDA Forest Service.

Owen DR; Lindahl KQ Jr; Wood DL; Parmeter JR Jr, 1987. Pathogenicity of fungi isolated from Dendroctonus valens, D. brevicomis, and D. ponderosae to ponderosa pine seedlings. Phytopathology, 77(4):631-636

Paine TD; Hanlon CC, 1991. Response of Dendroctonus brevicomis and Ips paraconfusus (Coleoptera: Scolytidae) to combinations of synthetic pheromone attractants and inhibitors verbenone and ipsdienol. Journal of Chemical Ecology, 17(11):2163-2176

Pajares JA; Lanier GN, 1990. Biosystematics of the turpentine beetles Dendroctonus terebrans and D. valens (Coleoptera: Scolytidae). Annals of the Entomological Society of America, 83(2):171-188

Parmeter JR Jr; Slaughter GW; Chen MM; Wood DL; Stubbs HA, 1989. Single and mixed inoculations of ponderosa pine with fungal associates of Dendroctonus spp. Phytopathology, 79(7):768-772

Phillips TW; Wilkening AJ; Atkinson TH; Nation JL; Wilkinson RC; Foltz JL, 1988. Synergism of turpentine and ethanol as attractants for certain pine-infesting beetles (Coleoptera). Environmental Entomology, 17(3):456-462

Pierce HD Jr; Conn JE; Oehlschlager AC; Borden JH, 1987. Monoterpene metabolism in female mountain pine beetles, Dendroctonus ponderosae Hopkins, attacking ponderosa pine. Journal of Chemical Ecology, 13(6):1455-1480

Raffa KF, 1991. Temporal and spatial disparities among bark beetles, predators, and associates responding to synthetic bark beetle pheromones: Ips pini (Coleoptera: Scolytidae) in Wisconsin. Environmental Entomology, 20(6):1665-1679

Rappaport NG; Owen DR; Stein JD, 2001. Interruption of semiochemical-mediated attraction of Dendroctonus valens (Coleoptera: Scolytidae) and selected nontarget insects by verbenone. Environmental Entomology, 30(5):837-841; [Available online at http://www.entsoc.org/pubs/ee/eetocs]; 28 ref.

Ross H; Arnett Jr, 2000. American Insects. Boca Raton, Florida, USA: St. Lucie Press, CRC Press.

Rudinsky JA, 1962. Ecology of Scolytidae. Annual Review of Entomology, 7:327-348.

Safranyik L; Shore TL; Carroll AL; Linton DA, 2004. Bark beetle (Coleoptera: Scolytidae) diversity in spaced and unmanaged mature lodgepole pine (Pinaceae) in southeastern British Columbia. Forest Ecology and Management, 200(1/3):23-38. http://www.sciencedirect.com/science/journal/03781127

Sanchez-Martinez G; Wagner MR, 2002. Bark beetle community structure under four ponderosa pine forest stand conditions in northern Arizona. Forest Ecology and Management, 170(1/3):145-160; many ref.

Schmid JM; Mata SA, 1991. Red turpentine beetles in partially cut stands of ponderosa pine. Research Note - Rocky Mountain Forest and Range Experiment Station, USDA Forest Service, No. RM-505:3 pp.

Schroeder LM; Lindelöw A, 1989. Attraction of scolytids and associated beetles by different absolute amounts and proportions of -pinene and ethanol. Journal of Chemical Ecology, 15(3):807-817

Six DL; Skov K, 2009. Response of bark beetles and their natural enemies to fire and fire surrogate treatments in mixed-conifer forests in western Montana. Forest Ecology and Management, 258(5):761-772. http://www.sciencedirect.com/science/journal/03781127

Sjödin K; Schroeder LM, Eidmann HH et al. , 1989. Attack rates of scolytids and composition of volatile wood constituents in healthy and mechanically weakened pine trees. Scandinavian Journal of Forestry Research, 4:379-391.

Smith RH, 1971. Red turpentine beetle [Dendroctonus valens]. For. Pest Leafl. US For. Serv. No. 55 (rev.) 1971. pp. 8.

Song YS; Yang AL; He NJ, 2000. Pest risk analysis of red turpentine beetle (Dendroctonus valens). Forest Pest and Disease, 6:34-37 (in Chinese).

Song ZQ; Liu X; Liang ZQ; Wang Y, 1993. Chemical characteristics of oleoresins from Chinese pine species for oleoresin production. Chemistry and Industry of Forest Products 13(Suppl.):27-32 (in Chinese).

Stark RW, 1965. Recent trends in forest entomology. Annual Review of Entomology, 10:303-324.

Stark RW; Miller PR; Cobb FW Jr; Wood DL; Parmerter JR Jr, 1968. Incidence of bark beetle infestation in injured trees. Hilgardia, 59:121-126.

Su Z; Zhai QH; Liang ZQ; Guo CT, 1981. Chemical constituents of oleoresins from nineteen pine tree species and their relationships to species and Matsucoccus matsumurea attack. Chemistry and industry of forest products, 1(3):73-76 (in Chinese).

Sun J; Gillette NE; Miao Z; Kang L; Zhang Z; Owen DR; Stein JD, 2003. Verbenone interrupts attraction to host volatiles and reduces attack on Pinus tabuliformis (Pinaceae) by Dendroctonus valens (Coleoptera: Scolytidae) in the People's Republic of China. Canadian Entomologist, 135(5):721-732.

Sun JH; Miao ZW; Zhang Z; Zhang ZN; Gillette N, 2004. Red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), response to host semiochemicals in China. Environmental Entomology, 33(2):206-212.

Sun SQ; Ying M; Ma SJ, 2002. The rotated principle component analysis on the regional features of summer precipitation in North China and their correlation analysis. Climatic and Environmental Research, 7(1):74-86 (in Chinese).

Sun Y; Wang QQ; Qian YF; Zhang YS, 2002. Seasonal precipitation characters in North China and its relations with precipitation in other parts of China. Journal of Nanjing Institute of Meteorology, 25(4):503-509 (in Chinese).

Tovar DC; Montiel JTM; Bolanos RC; Yates HO III; Lara JEF, 1995. Forest Insects of Mexico. Universidad Autonoma Chapingo, Estado de Mexico, Mexico.

Vité JP; Gara RI; Scheller HDV, 1964. Field observation on the response to attractions of bark beetles infesting Southern pines. Contribution of the Boyce Thompson Institute, 21:461-470.

Walker RE; Fecko RM; Frederick WB; Johnson DW; Miller WW, 2007. Forest health impacts of bark beetles, dwarf mistletoe, and blister rust in a Lake Tahoe Basin mixed conifer stand. Western North American Naturalist, 67(4):562-571. http://www.wnan.byu.edu

Weissmann G; Lange W, 1988. Investigation of Pinus tabulaeformis Carr. oleoresin. Chemistry and Industry of Forest Products, 8(2):1-9.

Werner RA, 1972. Aggregation behavior of the beetle Ips grandicollis in response to (1) host-produced attractants; (2) insect-produced attractants. Journal of Insect Physiology, 18:423-437.

White PR; Hobson KR, 1993. Stereospecific antennal response by red turpentine beetle, Dendroctonus valens to chiral monoterpenes from ponderosa pine resin. Journal of Chemical Ecology, 19(10):2193-2202

Wingfield MJ, 1983. Association of Verticicladiella procera and Leptographium terrebrantis with insects in the Lake States. Canadian Journal of Forest Research, 13(6):1238-1245

Wu G; Feng ZW, 1994. Study on the social characteristics and biomass of the Pinus tabulaeformis forest systems in China. Acta Ecologica Sinica, 14(1):415-422 (in Chinese).

Wu JG; Zhao MM; Zang CM; Guo BP; Li JZ; Li X, 2002. Damage of Dendroctonus valens on Pinus tabulaeformis and its distribution on trunk and root before and after overwintering period. Forest Pest and Disease, 3:38-41 (in Chinese).

Xu HC; Sun ZF; Guo GR; Feng L, 1981. Geographic distribution of Pinus tabulaeformis Carr. and classification of provenance regions. Scientia Silvae Sinicae, 17(3):258-270; 33 ref.

Xu HC; Tang Q; Zhang SJ; Ma H, 1986. A study on climatic ecotypes in Pinus tabulaeformis Carr. Scientia Silvae Sinicae, 22(1):10-20 (in Chinese).

Zhang LiYan; Chen QingChang; Zhang XiaoBo, 2002. Studies on the morphological characters and bionomics of Dendroctonus valens LeConte. Scientia Silvae Sinicae, 38(4):95-99; 11 ref.

Distribution Maps

Top of page
You can pan and zoom the map
Save map