Oemona hirta (lemon tree borer)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Risk and Impact Factors
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Principal Source
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Oemona hirta (Fabricius, 1775)
Preferred Common Name
- lemon tree borer
Other Scientific Names
- Aemona hirta Broun, 1880
- Oemona humilis Newman, 1840
- Saperda hirta Fabricius, 1775
- Saperda villosus Fabricius, 1801
Summary of InvasivenessTop of page
Oemona hirta is a cerambycine longhorn beetle native to New Zealand. Commonly referred to as the lemon tree borer, this beetle is in fact polyphagous, with larvae feeding on dozens of different trees and shrubs, which has become a major pest of several introduced crops, including Citrus spp., apple (Malus domestica), chestnut (Castanea sativa), walnut (Juglans regia), grape (Vitis vinifera), Macadamia spp. among others. O. hirta occurs throughout New Zealand (both islands) but is uncommon in very dry areas. Like many cerambycine longhorn beetles, adults of the species are nocturnal (feeding and mating at night), attracted to lights and are mainly active from December to March. Although this species is not known to be established outside of its native range, it was added to the EPPO A1 List in 2013 as a quarantine pest.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Coleoptera
- Family: Cerambycidae
- Genus: Oemona
- Species: Oemona hirta
Notes on Taxonomy and NomenclatureTop of page
Oemona hirta (Cerambycidae: Cerambycinae: Callidiopini) is a longhorn beetle native to New Zealand (Broun, 1893; Duffy, 1963; Tavakilian and Chevillotte, 2019). This species was originally described as Saperda hirta by Fabricius from specimens in the collection of Joseph Banks at the Natural History Museum (London, UK). Two other species have been synonymized under O. hirta: Saperda villosus and O. humilis. Lu and Wang (2005) have provided a thorough taxonomic revision of the genus, including a redescription and photographs of all taxa, phylogenetic analysis and a dichotomous key for identification. The genus Oemona currently contains three other valid species, all native to New Zealand: O. plicicollis, O. separata and O. simplicicollis.
DescriptionTop of page
Oemona hirta adults are rather unremarkable, medium-sized beetles, ranging from 11-31 mm in length, and are generally slender and somewhat cylindrical. The body is reddish brown to blackish brown, with elytra (hardened wing covers) generally brown to reddish brown. The pronotum is nearly cylindrical in shape and has 10-12 distinct transverse rugae (horizontal grooves) on the dorsal surface. Males and females are not strikingly dimorphic but are easily distinguished by the presence (in males) of distinct punctures on the lateral margins of the prothorax (females lack the punctures). In addition, males are generally smaller than females, antennae in males are slightly longer than the body, while in females, antennae are as long as or slightly longer than the body. Larvae are typical for cerambycines: creamy white, subcylindrical, 25-40 mm long and tiny legs. Pupae are generally 20-25 mm long with short, black abdominal spines which allow them to rotate within the pupal cell.
Distribution TableTop 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.Last updated: 14 Dec 2020
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|United Kingdom||Absent, Intercepted only|
|New Zealand||Present, Widespread||Native|
Risk of IntroductionTop of page
Oemona hirta was intercepted on Wisteria plants imported from New Zealand for planting in 1983 and 2010 in the UK. A rapid assessment of the risks posed to the UK concluded that this species could be a threat to forestry and amenity trees, commercial fruit crops and ornamental shrubs in the UK and also to other parts of Europe, and recommended the need for a more detailed Pest Risk Analysis (PRA) (FERA, 2010). The Working Party on Phytosanitary Regulations decided in 2011 that an EPPO PRA should be performed for the whole of the EPPO region (EPPO, 2014).
The similarities between the climate in parts of New Zealand (temperate oceanic) where O. hirta has been recorded and the climate in the EPPO region, suggest that large parts of the EPPO region would be climatically suitable for this pest (EPPO, 2014). Many of the host plants (fruit crops, woody ornamentals, forest trees) of this polyphagous pest species are of major economic importance in the EPPO region.
HabitatTop of page
Oemona hirta is native to New Zealand, which has a generally maritime temperate climate. Specimens have been collected in both native forests and orchards.
Habitat ListTop of page
|Terrestrial||Managed||Cultivated / agricultural land||Present, no further details||Natural|
|Terrestrial||Managed||Managed forests, plantations and orchards||Present, no further details||Natural|
|Terrestrial||Natural / Semi-natural||Natural forests||Present, no further details||Natural|
Hosts/Species AffectedTop of page
Oemona hirta is a highly polyphagous species whose original hosts were native species but it has expanded its host range to a large number of species exotic to New Zealand, particularly fruit and plantation trees. Although Citrus spp. are the major host plants, O. hirta attacks over 200 species from 81 families (Kuschel, 1990; EPPO, 2014). In the wild, O. hirta is listed as part of the invertebrate fauna of mangrove trees in New Zealand (Morrisey et al., 2007).
Host Plants and Other Plants AffectedTop of page
List of Symptoms/SignsTop of page
|Leaves / wilting|
|Leaves / yellowed or dead|
|Stems / internal feeding|
|Stems / lodging; broken stems|
|Stems / visible frass|
Biology and EcologyTop of page
Lu and Wang (2005) have provided a thorough review of the biology of O. hirta. In most of New Zealand, this species requires at least 2 years to complete its life cycle. Wang and Davis (2005) reported that adults are nocturnal and perform all essential activities (feeding on flowers, mating, oviposition) in the hours between sunset and sunrise. O. hirta lays its eggs between September and January. Eggs are laid one at a time in fresh wounds (from pruning), at the bases of leaves, or in cracks in the bark of trees and shrubs (Wang and Davis, 2005). The larval stage lasts more than 1 year. Newly hatched larvae bore directly into sapwood and then into hardwood. Developing larvae tunnel into branches and create holes every few inches to eject waste (frass). Before entering the pupal phase, larvae seal themselves in their tunnel with thin strips of wood packed into tight plugs about 2-2.5 cm in length. The pupal period requires about 21 days to complete and pupae can be found in the field between late May and early November (Wang and Davis, 2005). According to Hosking (1978), adults are mainly active during the summer months (December-March). Wang and Davis (2005) noted that adults emerge between early September and early February, with a noticeable peak in emergence seen between October and December.
The mating behaviour of O. hirta has been described by Wang and Davis (2005); an account of their development, longevity, reproductive potential and daily reproductive rhythms under different rearing conditions is given by Wang et al. (1998) and Wang et al. (2002). Adults that emerged from pupae collected in the field laid up to 50 eggs during their lifespan. On average, larval development in the laboratory takes 150-300 days, while the pupal stage lasted between 15 and 29 days.
ClimateTop of page
|C - Temperate/Mesothermal climate||Preferred||Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C|
Natural enemiesTop of page
Notes on Natural EnemiesTop of page
Wang and Shi (2001) studied the host preference and sex allocation of three hymenopteran parasitoid species known to attack O. hirta. These natural enemies are Xanthocryptus novozealandicus (Hymenoptera: Ichneumonidae), Campoplex sp. (Hymenoptera: Ichneumonidae) and Aspicolpus hudsoni (Hymenoptera: Braconidae). In addition, Hosking (1978) reported that the fungus Cordyceps aemonae (Cordycipitaceae) attacks larvae of O. hirta.
In field trials conducted in New Zealand, suspensions of infective juveniles of Neoplectana feltiae [Steinernema feltiae] were injected into O. hirta-infected orange and grape trees through larval tunnels. After one month, 5% of borer populations were still alive (Clearwater and Wouts, 1980).
ImpactTop of page
Oemona hirta is a pest of hosts that are important economically or environmentally in New Zealand. It attacks many trees grown for fruit (e.g. citrus, apple or persimmon), in forests and plantations (e.g. oak and poplar) or in the wild (e.g. endemic species such as the New Zealand mangroves) (Morrisey et al., 2007). Larvae boring into branches or stems are responsible for the main damage, possibly causing death of branches, reduced growth and have an impact on yield and long-term productivity of fruit trees (Taylor, 1957; Wang and Shi, 1999).
Risk and Impact FactorsTop of page
- Has a broad native range
- Abundant in its native range
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Host damage
- Negatively impacts agriculture
- Damages animal/plant products
- Highly likely to be transported internationally accidentally
- Difficult to identify/detect in the field
- Difficult/costly to control
Detection and InspectionTop of page
Signs of O. hirta larval presence such as tunnels, excretion holes and frass may be observed on leaves, stems and twigs. Eggs are relatively large (about 2 mm in length) but are usually laid in cuts or cracks and may not be visible. Larvae may not be detected until several excretion holes are visible. Adult specimens are medium-sized (15-25 mm long) and mostly nocturnal, hiding under leaves during the day.
A technique based on sound detection for the detection of O. hirta larvae in wood is described by Rohitha et al. (1994). Unfortunately, this method can only be used under laboratory conditions as the sample has to be placed in an acoustically isolated chamber for the detection of sounds produced by the larvae.
Similarities to Other Species/ConditionsTop of page
Oemona hirta is very similar in general appearance to the other three species described in the genus: O. plicicollis, O. separata and O. simplicicollis. In their revision of the genus Oemona, Lu and Wang (2005) provide detailed morphological descriptions of the genus and all four described species, along with a dichotomous key to separate the four species.
Prevention and ControlTop of page
Due 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.
Longhorn beetles are generally difficult to control due to the fact that larvae and pupae develop within the host which confers protection from foliar insecticide treatments and from most predators. Destroying the infested plant is the only fully effective way of controlling the larvae. Insecticide sprays may be effective against adults, as long as they are in contact with the treatment or feed on treated foliage (Ostojá-Starzewski et al., 2010).
A description of the damage caused by, and control of, O.hirta on lemon trees in New Zealand is given by Sale (1993). Measures recommended for control include pruning and burning severely damaged twigs or branches and injecting less severely damaged branches with kerosene, petrol or insecticide. Prevention is emphasized as being a worthwhile approach and cleanly cutting back broken branches and sealing pruning cuts are some of the steps recommended.
Results from field trials in New Zealand suggest injecting suspensions of the nematode Neoplectana feltiae [Steinernerma feltiae] into infected branches might be effective in controlling O. hirta (Clearwater and Wouts, 1980; Wouts and Clearwater, 1980).
ReferencesTop of page
APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacific region. Technical Document No. 135. Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA)
Broun, T, 1893. Manual of the New Zealand Coleoptera. Parts V, VI, VII, Wellington, New Zealand: Samuel Costall.
Clearwater JR, Wouts WM, 1980. Preliminary trials on the control of lemon tree borer with nematodes. [Proceedings of the 33rd New Zealand Weed and Pest Control Conference, Tauranga, New Zealand, 12-14 August 1980 ], [ed. by Hartley MJ]. Palmerston North, New Zealand: New Zealand Weed and Pest Control Society Inc. 133-135.
Clearwater, JR, 1981. Lemon tree borer, Oemona hirta (Fabricius), life cycle. In: DSIR Information Service , (105/33)
EPPO, 2014. Revised Pest Risk Analysis for Oemona hirta. Paris, France: European and Mediterranean Plant Protection Organization (EPPO).84 pp.
FERA, 2010. Rapid assessment of the need for a detailed Pest Risk Analysis for Oemona hirta, the lemon-tree borer. York, UK: Food and Environment Research Agency (FERA).8 pp. https://secure.fera.defra.gov.uk/phiw/riskRegister/downloadExternalPra.cfm?id=3889
Hudson, GV, 1934. New Zealand beetles and their larvae: an elementary introduction to the study of our native Coleoptera, Wellington, New Zealand: Ferguson and Osborne.236 pp.
Kuschel, G., 1990. Beetles in a suburban environment: a New Zealand case study. The identity and status of Coleoptera in the natural and modified habitats of Lynfield, Auckland (1974-1989). In: DSIR Plant Protection Report , (No. 3) . 119 pp.
Lu, W, Wang, Q, 2005. Systematics of the New Zealand longicorn beetle genus Oemona Newman with discussion of the taxonomic position of the Australian species, O. simplex White (Coleoptera: Cerambycidae: Cerambycinae). Zootaxa, 971(1), 1-31.
Morrisey D, Beard C, Morrison M, Craggs R, Lowe M, 2007. The New Zealand mangrove: review of the current state of knowledge. (Auckland Regional Council Technical Publication Number 325) . Auckland, New Zealand: Auckland Regional Counci.156 pp. https://www.aucklandcouncil.govt.nz/plans-projects-policies-reports-bylaws/our-plans-strategies/unitary-plan/history-unitary-plan/docs332mangroves/Appendix-3.32.2.pdf
Ostojá-Starzewski J, MacLeod A, Eyre D, 2010. Plant pest factsheet: lemon tree borer, Oemona hirta. York, UK: Food and Environment Research Agency (FERA).3 pp. https://planthealthportal.defra.gov.uk/assets/factsheets/lemonTreeBorer.pdf
Qiao Wang, Shi GuangLu, Davis, L. K., 1998. Reproductive potential and daily reproductive rhythms of Oemona hirta (Coleoptera: Cerambycidae). Journal of Economic Entomology, 91(6), 1360-1365. doi: 10.1093/jee/91.6.1360
Rohitha, B. H., Calvert, P. R., Hill, R. A., 1994. An acoustic technique for recording lemon tree borer activity in the laboratory. In: Proceedings of the Forty Seventh New Zealand Plant Protection Conference, Waitangi Hotel, New Zealand, 9-11 August, 1994 [Proceedings of the Forty Seventh New Zealand Plant Protection Conference, Waitangi Hotel, New Zealand, 9-11 August, 1994], [ed. by Popay, A. J.]. Rotorua, New Zealand: New Zealand Plant Protection Society. 359-361.
Tavakilian GL, Chevillotte H, 2019. Titan: international database on Cerambycidae or longhorn beetles. Version 4.0. (Titan: base de données internationales sur les Cerambycidae ou Longicornes. Version 4.0). France: http://titan.gbif.fr/index.html
Taylor HS, 1957. Citrus borer. New Zealand Journal of Agriculture, 94(4), 357-358.
Wang Qiao, Davis, L. K., 2005. Mating behavior of Oemona hirta (F.) (Coleoptera: Cerambycidae: Cerambycinae) in laboratory conditions. Journal of Insect Behavior, 18(2), 187-191. doi: 10.1007/s10905-005-0474-y
Wang Qiao, Shi GuangLu, Song DePing, Rogers, D. J., Davis, L. K., Chen Xiong, 2002. Development, survival, body weight, longevity, and reproductive potential of Oemona hirta (Coleoptera: Cerambycidae) under different rearing conditions. Journal of Economic Entomology, 95(3), 563-569. doi: 10.1603/0022-0493-95.3.563
Wang, Q., Shi, G. L., 1999. Parasitic natural enemies of lemon tree borer. In: Proceedings of the Fifty Second New Zealand Plant Protection Conference, Auckland Airport Centra, Auckland, New Zealand, 10-12 August, 1999,[ed. by O'Callaghan, M.]. Rotorua, New Zealand: New Zealand Plant Protection Society. 60-64.
Wang, Q., Shi, G., 2001. Host preference and sex allocation of three hymenopteran parasitoid species (Ichneumonidae and Braconidae) of a longicorn pest, Oemona hirta (Fabr.) (Col., Cerambycidae). Journal of Applied Entomology, 125(8), 463-467. doi: 10.1046/j.1439-0418.2001.00582.x
Wouts WM, Clearwater JR, 1980. Neoaplectana feltiae, a biological insecticide against the lemon tree borer. In: New Zealand of Zoology [Abstracts of papers. Proceedings, 8th Annual General Meeting of the New Zealand Society for Parasitology, Palmerston North, New Zealand, 20-22 August 1980], 7(4) . 605.
Broun T, 1893. Manual of the New Zealand Coleoptera. Parts V, VI, VII. Wellington, New Zealand: Samuel Costall.
Clearwater JR, 1981. Lemon tree borer, Oemona hirta (Fabricius), life cycle. In: DSIR Information Service,
Hudson GV, 1934. New Zealand beetles and their larvae: an elementary introduction to the study of our native Coleoptera. Wellington, New Zealand: Ferguson and Osborne. 236 pp.
Lu W, Wang Q, 2005. Systematics of the New Zealand longicorn beetle genus Oemona Newman with discussion of the taxonomic position of the Australian species, O. simplex White (Coleoptera: Cerambycidae: Cerambycinae). Zootaxa. 971 (1), 1-31.
Qiao Wang, Shi GuangLu, Davis L K, 1998. Reproductive potential and daily reproductive rhythms of Oemona hirta (Coleoptera: Cerambycidae). Journal of Economic Entomology. 91 (6), 1360-1365. DOI:10.1093/jee/91.6.1360
Wang Q, Shi G L, 1999. Parasitic natural enemies of lemon tree borer. In: Proceedings of the Fifty Second New Zealand Plant Protection Conference, Auckland Airport Centra, Auckland, New Zealand, 10-12 August, 1999. [ed. by O'Callaghan M]. Rotorua, New Zealand: New Zealand Plant Protection Society. 60-64.
Wang Q, Shi G, 2001. Host preference and sex allocation of three hymenopteran parasitoid species (Ichneumonidae and Braconidae) of a longicorn pest, Oemona hirta (Fabr.) (Col., Cerambycidae). Journal of Applied Entomology. 125 (8), 463-467. DOI:10.1046/j.1439-0418.2001.00582.x
Wang Qiao, Davis L K, 2005. Mating behavior of Oemona hirta (F.) (Coleoptera: Cerambycidae: Cerambycinae) in laboratory conditions. Journal of Insect Behavior. 18 (2), 187-191. DOI:10.1007/s10905-005-0474-y
Wang Qiao, Shi GuangLu, Song DePing, Rogers D J, Davis L K, Chen Xiong, 2002. Development, survival, body weight, longevity, and reproductive potential of Oemona hirta (Coleoptera: Cerambycidae) under different rearing conditions. Journal of Economic Entomology. 95 (3), 563-569. DOI:10.1603/0022-0493-95.3.563
Principal SourceTop of page
Draft datasheet under review
ContributorsTop of page
16/11/2019 Original text by:
Eugenio H Nearns, National Museum of Natural History, Smithsonian Institution, Washington DC, USA
Distribution MapsTop of page
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