Scolytus schevyrewi (banded elm bark beetle)
Index
- Pictures
- Identity
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Distribution
- Distribution Table
- Risk of Introduction
- Habitat
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Symptoms
- List of Symptoms/Signs
- Biology and Ecology
- Notes on Natural Enemies
- Plant Trade
- Wood Packaging
- Impact
- Environmental Impact
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Distribution Maps
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Top of pagePreferred Scientific Name
- Scolytus schevyrewi Semenov, 1902
Preferred Common Name
- banded elm bark beetle
Other Scientific Names
- Eccoptogaster emarginatus Wichmann, 1915
- Eccoptogaster transcaspicus Eggers, 1922
- Scolytus frankei Wichmann, 1915
- Scolytus seulensis Murayamas, 1930
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Coleoptera
- Family: Scolytidae
- Genus: Scolytus
- Species: Scolytus schevyrewi
Notes on Taxonomy and Nomenclature
Top of pageDescription
Top of pageScolytidae eggs are smooth, ovoid, white and translucent. The eggs of S. schevyrewi are approximately 1 mm long and individually deposited along opposite sides of the egg gallery.
Larvae
All scolytidae larvae are similar in appearance and difficult to separate. They are white, 'C'-shaped and legless. The head capsule is lightly sclerotized and amber with dark, well-developed mouthparts. Each of the abdominal segments has two to three tergal folds and the pleuron is not longitudinally divided. The larvae do not change in appearance as they grow. The larvae of S. schevyrewi undergo five instars and are 4.8-7.5 mm long when mature.
Pupae
Scolytid pupae are white and mummy-like. They are exarate, with legs and wings free from the body. Some species have paired abdominal urogomphi. The elytra are either rugose or smooth, sometimes with a prominent head and thoracic tubercles.
Adults
Beetles of the genus Scolytus are characterized as follows: the eyes are slightly emarginated; the antennal club is large and oval with sutures medially bowed in an acute angle; the pronotum is large; the anterior is constricted; the post and lateral margins are sharply bordered; the elytra are flat with the abdomen rising from the second sternite to the apices; the tibiae are smooth laterally and posses a long curved distal tooth; and the third tarsal segments are bilobed (Grüne, 1979).
S. schevyrewi adults are 3.2-4.2 mm long (average 3.6 mm). They are reddish-brown and the head is black. The frons is slightly protruding with striae running toward the clypeus in the females but with yellow, inwardly curved frontal hairs on the peripheral edges in the males. The elytra are red-brown to black-brown, with slightly runcinate lateral and posterior margins. A slightly darker transverse fascia (band), 1.9 mm long and 1.6 mm wide, may exist in some individuals. The sterna are extremely retracted toward the notum from the second segment and beyond, resulting in an obtuse angle with the first sternite. The process on the second sternite is black, flat and wide at the tip. The seventh tergum of the male contains a pair of long setae (Michalski, 1973; Yin et al., 1984; Li et al., 1987; Wang, 1992).
Distribution
Top of pageDistribution Table
Top of pageThe 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.
Last updated: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Asia |
|||||||
China | Present, Localized | Native | Invasive | ||||
-Hebei | Present, Widespread | Native | Invasive | ||||
-Heilongjiang | Present, Widespread | Native | Invasive | ||||
-Henan | Present, Widespread | Native | Invasive | ||||
-Ningxia | Present, Widespread | Native | Invasive | ||||
-Qinghai | Present, Widespread | Native | Invasive | ||||
-Shaanxi | Present, Widespread | Native | Invasive | ||||
-Xinjiang | Present, Widespread | Native | Invasive | ||||
Kazakhstan | Present | Native | Invasive | ||||
Kyrgyzstan | Present | Native | Invasive | ||||
Mongolia | Present | Native | Invasive | ||||
North Korea | Present | Native | Invasive | ||||
South Korea | Present | Native | Invasive | ||||
Tajikistan | Present | Native | Invasive | ||||
Turkmenistan | Present | Native | Invasive | ||||
Uzbekistan | Present | Native | Invasive | ||||
Europe |
|||||||
Russia | Present | ||||||
-Eastern Siberia | Present | Native | Invasive | ||||
-Russian Far East | Present | Native | Invasive | ||||
North America |
|||||||
Canada | Present | ||||||
-Alberta | Present | ||||||
-British Columbia | Present | ||||||
-Manitoba | Present | ||||||
-Ontario | Present | ||||||
-Saskatchewan | Present | ||||||
Mexico | Present | ||||||
United States | |||||||
-Arizona | Present | ||||||
-California | Present | ||||||
-Colorado | Present, Widespread | Introduced | Invasive | ||||
-Connecticut | Present, Localized | ||||||
-Delaware | Present | ||||||
-Idaho | Present | ||||||
-Illinois | Present | ||||||
-Indiana | Present | ||||||
-Kansas | Present, Widespread | Introduced | Invasive | ||||
-Maryland | Present | ||||||
-Michigan | Present | ||||||
-Minnesota | Present | ||||||
-Missouri | Present | ||||||
-Montana | Present | ||||||
-Nebraska | Present | ||||||
-Nevada | Present | ||||||
-New Jersey | Present | ||||||
-New Mexico | Present, Localized | Introduced | Invasive | ||||
-North Dakota | Present | ||||||
-Ohio | Present, Localized | ||||||
-Oklahoma | Present | ||||||
-Oregon | Present | ||||||
-Pennsylvania | Present, Localized | ||||||
-South Dakota | Present | ||||||
-Texas | Present, Localized | ||||||
-Utah | Present, Widespread | Introduced | Invasive | ||||
-Virginia | Present, Localized | ||||||
-Washington | Present | ||||||
-Wyoming | Present |
Risk of Introduction
Top of pageThe life stages of this insect that are present in the cambium or bark can easily be transported via international trade in unprocessed elm logs or pallets, wooden crates or dunnage, containing bark strips. The infestations recently detected in the USA probably originated several years prior to their discovery, from infested solid wood packing material used in international trade. This insect was found in the vicinity of solid wood packing material recycling centres near Denver, Colorado (NAPPO, 2003). Nevertheless, no records exist of interceptions of S. schevyrewi at USA ports of entry. However, 102 interceptions of Scolytus sp. were made between 1985 and 2000 from Belgium, Canada, Russia and Italy (Haack, 2001). Some of the interceptions from Russia may have been S. schevyrewi.
Elms (Ulmus spp.), which are the primary hosts of S. schevyrewi, comprise of approximately 45 recognized species found in Eurasia, North and Central America (Little, 1979). Many species of elms are popular ornamental trees in urban areas throughout the temperate regions of the world, including several countries in the southern hemisphere. Elms are also popular species for shelterbelt and windbreak plantings, and veneer quality lumber. The introduction and establishment of another potentially damaging pest of elms, especially one that is a vector of Dutch elm disease, could have widespread impacts on the future use of this group of popular, multi-purpose trees.
Habitat
Top of pageHosts/Species Affected
Top of pageIn Asia, Ulmus spp. (elms) are the primary hosts. Elms that are known hosts of this insect in its geographic range include Ulmus pumila (Siberian elm), Ulmus laevis (European white elm), Ulmus davidiana var. japonica (Japanese elm), Ulmus macrocarpa, Ulmus carpinifolia [Ulmus minor] (European field elm) and Ulmus propinqua [Ulmus japonica]. In North America, Ulmus americana (American elm) and Ulmus thomasii (rock elm) have been reported as hosts.
Other reported hosts in the geographic range of S. schevyrewi include Salix babylonica (Babylon weeping willow), Elaeagnus spp., Caragana korshinskii, Malus pumila (paradise apple), Prunus padus (bird cherry), Prunus ansu (ansu apricot), Prunus salicina (Japanese plum), Prunus persica (momo), Prunus yedoensis (Tokyo cherry), Prunus pseudocerasus (Chinese sour cherry), Prunus glandulosa (dwarf flowering almond), Prunus amygdalus [Prunus dulcis] and Pyrus bretschneideri (Michalski, 1973; Krivolutskaya, 1983; Yin et al., 1984; Li et al., 1987; Yang et al., 1988; Wang, 1992; Bright and Skidmore, 2002).
Host Plants and Other Plants Affected
Top of pagePlant name | Family | Context | References |
---|---|---|---|
Caragana korshinskii (Korshinsk pea shrub) | Fabaceae | Other | |
Elaeagnus | Elaeagnaceae | Other | |
Prunus amygdalus | Rosaceae | Other | |
Prunus ansu | Other | ||
Prunus glandulosa (flowering almond) | Rosaceae | Other | |
Prunus padus (bird cherry) | Rosaceae | Other | |
Prunus persica (peach) | Rosaceae | Other | |
Prunus pseudocerasus (chinese fruiting cherry) | Rosaceae | Other | |
Prunus salicina (Japanese plum) | Rosaceae | Other | |
Prunus yedoensis | Rosaceae | Other | |
Pyrus bretschneideri (yali pear) | Rosaceae | Other | |
Salix babylonica (weeping willow) | Salicaceae | Other | |
Ulmus americana (American elm) | Ulmaceae | Main | |
Ulmus davidiana (japanese elm) | Ulmaceae | Main | |
Ulmus laevis (Russian white elm) | Ulmaceae | Main | |
Ulmus macrocarpa | Ulmaceae | Main | |
Ulmus minor (European field elm) | Ulmaceae | Main | |
Ulmus pumila (dwarf elm) | Ulmaceae | Main | |
Ulmus thomasii (rock elm) | Ulmaceae | Main |
Symptoms
Top of pageList of Symptoms/Signs
Top of pageSign | Life Stages | Type |
---|---|---|
Leaves / yellowed or dead | ||
Stems / gummosis or resinosis | ||
Stems / visible frass | ||
Whole plant / frass visible | ||
Whole plant / plant dead; dieback |
Biology and Ecology
Top of pageIn China, S. schevyrewi typically undergoes two to three overlapping generations a year, depending on its location. This insect overwinters as either mature larvae inside the pupal chamber or as adults under the bark. The adults emerge from overwintering sites in late April to early May, and begin to search for and attack suitable host trees. Studies in Tajikistan indicated that S. schevyrewi has three to four generations per year in central Asia (Makhmadzieev and Shukronaev, 1983).
The larvae of the first generation develop in May and June, and become adults by early July. By late August, most second-generation larvae construct pupal chambers and begin to overwinter. However, some individuals continue to develop and complete a third generation before winter if the temperatures are favourable (Li et al., 1987; Yang et al., 1988; Wang, 1992).
Newly developed adults remain in their pupal chambers for 2 to 5 days before boring a 1.6-2.0 mm round exit hole through the bark. Adult emergence mostly occurs between 14.00 h and 20.00 h. The sex ratio is slightly female biased (1.0 females: 0.9 males). The new adults walk along the trunk for the first 30 minutes after emergence and before initiating flight. The adults are most active during warm and sunny weather.
Maturation feeding occurs on the bark at the intersections of tender twigs. However, in Tajikistan, studies on S. schevyrewi and several other species of Scolytus indicated that these insects could reproduce without maturation feeding (Makhmadzieev and Shukronaev, 1983). Following maturation feeding, the females attack host trees by constructing individual entrance holes through the bark. It is believed that the females release a pheromone to attract the males to the entrance hole. Mating occurs on the bark surface at the entrance hole and lasts for 1 to 8 minutes (average of 5 minutes). Both the males and females can mate more than once.
Since mating occurs on the bark surface, the egg galleries do not contain nuptial chambers. Each female constructs a single egg gallery in the cambium with individual egg niches along the gallery wall. The egg gallery is a single, vertical tunnel, typically located above the entrance hole and is an average of 4 to 6 cm (maximum 9 cm) long. The egg niches are closely arranged on each side of the gallery and sealed with a mixture of sawdust and adhesive secretions. The egg galleries usually contain an average of about 60 eggs with a range of 23 to 123 eggs. The females guard the entrance hole of their egg galleries until their death (Li et al., 1987; Wang, 1992).
The eggs hatch in the order in which they were laid. The newly hatched larvae feed in the cambium and construct individual galleries. The larval galleries are at first perpendicular to the egg gallery but later turn upwards or downwards. Some larval galleries meander or cross each other. High larval densities lead to complete girdling of the cambium and eventually tree death. There are five larval instars. When feeding is completed, the mature larvae construct pupal chambers in the outer bark, at the end of their galleries and pupate (Li et al., 1987; Wang, 1992).
The duration of each life stage is related to temperature (Li et al., 1987; Yang et al., 1988; Wang 1992). For example, at 26°C, the egg stage is 3 to 5 days (average 3.8 days), the larval stage is 18 to 23 days (average 21.0 days), the pupal stage is 5 to 7 days (average 6.0 days) and the adult stage is 6 to 43 days (average 20 days). Typically, 40 to 45 days are required to complete one generation under field conditions (Wang, 1992).
Notes on Natural Enemies
Top of pagePlant Trade
Top of pagePlant parts liable to carry the pest in trade/transport | Pest stages | Borne internally | Borne externally | Visibility of pest or symptoms |
---|---|---|---|---|
Stems (above ground)/Shoots/Trunks/Branches | arthropods/adults; arthropods/eggs; arthropods/larvae; arthropods/nymphs; arthropods/pupae | Yes | Pest or symptoms usually visible to the naked eye |
Wood Packaging
Top of pageWood Packaging liable to carry the pest in trade/transport | Timber type | Used as packing |
---|---|---|
Solid wood packing material with bark | Elm and other broadleaf trees; crating, dunnage, pallets | Yes |
Wood Packaging not known to carry the pest in trade/transport |
---|
Loose wood packing material |
Non-wood |
Processed or treated wood |
Solid wood packing material without bark |
Impact
Top of pageObservations along the northern Colorado Front Range, USA, indicated that S. schevyrewi is invading and killing ornamental elms in urban ecosystems (R Haack, USDA, personal communication, 2003). Some of its host trees, such as Ulmus pumila and Salix spp. are widely used as ornamental trees, as well as for windbreaks and shelterbelt-plantings, throughout much of central and western North America. The establishment of S. schevyrewi in these areas could result in severe damage.
Another economic concern regarding S. schevyrewi is its potential to function as a vector of new species of exotic tree-killing fungi, although none have been isolated to date. In addition, S. schevyrewi could be an efficient vector of the fungi that cause Dutch elm disease: Ophiostoma ulmi and Ophiostoma novo-ulmi. It is possible that S. schevyrewi could serve as a vector of the Dutch elm disease pathogens in areas where the smaller European elm bark beetle, Scolytus multistriatus does not already occur (Shi and Chen, 1990).
Environmental Impact
Top of pageIn the USA, several of its known hosts, including Ulmus pumila and Elaeagnus spp. have escaped cultivation in parts of central and western North America and are considered to be invasive plants. Therefore, this insect has a potential beneficial environmental effect, i.e. causing the death of undesired exotic trees that have escaped cultivation and are displacing native plants.
Detection and Inspection
Top of pageSimilarities to Other Species/Conditions
Top of pagePrevention and Control
Top of pageDue to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Cultural ControlIn Asia, the most effective control method against S. schevyrewi involves the maintenance of tree vigour, coupled with cultural practices such as the sanitation-felling of wilting and dying trees (Li et al., 1987; Yang et al., 1988). Cutting and rapid removal of infested trees before brood emergence and the destruction of bark by chipping have been used to treat infestations in the USA.
Biological Control
Relatively little is known about the natural enemy complex that is associated with S. schevyrewi. Therefore, biological control tactics have not been developed for this insect. However, its recent introduction into the USA and the probable lack of natural enemies in this new environment, make it a candidate for a classical biological control programme.
Chemical Control
Topical insecticide treatment of infested trunks to prevent adult emergence has been carried out in China. Soil drenching with systematic insecticides will reportedly kill the larvae (Li et al., 1987; Yang et al., 1988).
Pheromonal Control
Methods of control using pheromones have not been developed for S. schevyrewi.
Field Monitoring
The adults are attracted to funnel traps baited with either commercial Ips lures (ipsenol and ipsdienol) or Scolytus multistriatus lures [alpha-multistriatin plus 4-methyl-3-heptanol (threo isomer)] and alpha-Cubenene.
Funnel traps, baited with commercial Ips lures, established as part of an USDA APHIS/Forest Service Rapid Detection/Response Pilot Project, led to the initial detection of S. schevyrewi in Colorado and Utah, USA (NAPPO, 2003). Follow-up surveys are presently being carried out with S. multistriatus lures.
Integrated Pest Management
Presently relatively little is known about this insect or its ability to cause severe damage to elms in North America. Existing IPM tactics are limited to monitoring for the occurrence of S. schevyrewi with pheromone-baited traps (ensuring that arborists and extension services in North America are aware of this new potential pest), the rapid removal of infested trees and the destruction of the bark prior to brood emergence.
References
Top of pageBright DE; Skidmore RE, 2002. A catalogue of Scolytidae and Platypodidae (Coleoptera), Supplement 2 (1995-1999). Ottawa, Canada: NRC Research Press, 523 pp.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Furniss RL; Carolin VM, 1977. Western Forest Insects. Washington DC, USA: US Department of Agriculture Forest Service, Miscellaneous Publication No. 1339.
Grüne S, 1979. Handbuch zur bestimmung der Europäischen Borkenkäfer (Brief illustrated key to European bark beetles). Hannover, Germany: Verlag M & H Schapfer.
Haack RA, 2001. Intercepted Scolytidae (Coleoptera) at US ports of entry: 1985-200. Integrated Pest Management Reviews 6: 253-282.
Houping Liu; Haack RA, 2003. Scolytus schevyrewi. Exotic Forest Pest Information System (EXFOR). http://spfnic.fs.fed.us/exfor.
Krivolutskaya GO; Kupyanskaya AN, 1970. Bark beetles (Coleoptera, Ipidae) in urban shade-tree plantations of Primorskiy Kray. Entomological Research in the Far East 1, 185-195.
Li Q-X; Jiang X-M; Liu F-Z, 1987. Preliminary study on the biology of elm bark beetle Scolytus schevyrewi (Coleoptera: Scolytidae). Journal of August 1st Agriculture College, (3):12-18.
Little EL, 1979. Checklist of United States trees (Native and naturalized). USDA Forest Service, Agriculture Handbook 541.
Liu H-Z, 1988. Investigation of dying elms with reference to the existence of Dutch elm disease in China. Forest Research, 1:405-413.
Michalski J., 1973. Revision of the paleartic species of the Scolytus Geoffroy (Coleoptera, Scolytidae). Warszava, Krakow: Panstwowe Wydawnictwo Naukowe.
NAPPO, 2003. Detection of Scolytus schevyrewi Semenov in Colorado and Utah. http://www.pestalert.org/notifications.cfm?region=United%20States.
Semenov T-S; Pterovic A, 1902. Novae Sloytidarum species e fauna Rossidae et Asiae centralis (Coleoptera). Entomologicheskowoe Obozrenie, 2:265-273.
Wang Z-T, 1992. Scolytus schevyrewi Semenov. In: Xiao G-R, ed. Forest Insects of China (2nd edition). Beijing, China: China Forestry Publishing House, 633-634.
Wood SL, Bright Jr. DE, 1992. A catalog of Scolytidae and Platypodidae (Coleoptera), Part 2: Taxonomic Index. Provo, Utah, USA: Bringham Young University, Great Basin Naturalist Memoir No. 13.
Yang P-H; Hu Z-L; Zhao Z-L; Gao Y-T; Liu Y-J, 1988. A preliminary observation on the bionomics of Scolytus schevyrewi Semenov. Shaanxi Forest Science and Technology, 38-41.
Yin H-F; Huang F-S; Li Z-L; eds, 1984. Economic Insect Fauna of China, Fasc. 29, Coleoptera: Scolytidae. Beijing: Science Press, 205 pp.
Distribution References
Bright DE, Skidmore RE, 2002. A catalogue of Scolytidae and Platypodidae (Coleoptera), Supplement 2 (1995-1999)., Ottawa, Canada: NRC Research Press. 523 pp.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Houping Liu, Haack RA, 2003. Scolytus schevyrewi. In: Exotic Forest Pest Information System (EXFOR), http://spfnic.fs.fed.us/exfor
NAPPO, 2003. Detection of Scolytus schevyrewi Semenov in Colorado and Utah., http://www.pestalert.org/notifications.cfm?region=United%20States
Wood SL, Bright DE, 1992. A catalog of Scolytidae and Platypodidae (Coleoptera), Part 2: Taxonomic Index. In: Great Basin Naturalist Memoirs, 13 1-833.
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