First report of Ophiomyia kwansonis in Slovenia: addition to the EPPO Alert List
In Slovenia, larvae of an unusual leafminer belonging to the genus Ophiomyia (Diptera: Agromyzidae) were found in Hemerocallis spp. (daylilies) at 4 localities (2 private gardens, 1 public park, 1 botanical garden) in Ljubljana in autumn 2011. Silvery tunnels were observed on leaves of H. fulva, H. lilioasphodelus and some other Hemerocallis species. Six Ophiomyia species are known to occur in Slovenia but the larvae did not belong to any of these species. Ophiomyia specimens were reared in the laboratory and identified as Ophiomyia kwansonis by the official laboratory of the Slovenian Forestry Institute. As this represented a new agromyzid species for Slovenia, the identity of the pest was confirmed by an expert taxonomist (Mr Miloš Černý, Halenovice, Czech Republic) in 2012. No phytosanitary measures were taken in Slovenia.
The pest status of Ophiomyia kwansonis in Slovenia is officially declared as: Transient: non-actionable.
Note: In 2012, the pest was found at 6 new locations in Ljubljana and its surroundings within a radius of approximately 50 km, showing that the pest has been able to overwinter in Slovenia (Jurc et al., 2012).
Ophiomyia kwansonis (Diptera: Agromyzidae) – daylily leafminer
Why: Ophiomyia kwansonis is a leafminer of Hemerocallis species (daylilies) which until recently was only known to occur in Japan and Taiwan. In 2011, it was introduced into the USA where it spread rapidly. The same year, it was detected for the first time in Europe, in Slovenia. Considering the invasive behaviour of this new daylily leafminer, the EPPO Secretariat decided to add O. kwansonis to the EPPO Alert List.
Where: O. kwansonis originates from Asia. In the USA, the first indication of its presence is an image taken in July 2006 in Kennebunk, Maine. In 2008, damage was noticed by daylily amateurs at a national meeting in Texas, and by 2012 it was recorded in at least 15 US states. In Slovenia, it was first found in 2011 in the city of Ljubljana, and again in 2012 in Ljubljana and its surroundings, suggesting that the pest has been able to overwinter and spread.
EPPO region: Slovenia.
Asia: Japan, Taiwan.
North America: USA (Alabama, Florida, Georgia, Louisiana, Maine, Maryland, Mississippi, North Carolina, New York, South Carolina, Pennsylvania, Tennessee, Texas, Virginia and West Virginia).
On which plants: Hemerocallis spp. (including Hemerocallis fulva, H. lilioasphodelus).
Damage: Larvae feed on Hemerocallis leaves, mining up and down between the leaf surfaces, leaving obvious silver tunnels. Larvae are yellowish, up to 5 mm long, with protruding black anterior and posterior spiracles. Pupation occurs inside the mines, usually near the leaf base. Pupae are 3-3.5 mm long, orange-brown except for black anterior and posterior spiracles that protrude prominently as in larvae. Adults are small black flies (2 mm length) with red eyes and clear wings which can be seen resting on daylily blooms. Female oviposit in the leaf blade, often at or near its tip. No plant mortality has been reported but severe mining strongly disfigures daylilies which are grown for ornamental purposes. In Japan, there are three generations per year (2 in May-July and 1 in September-October). In Florida (US), it seems that the insect can breed continuously at least from March to September, probably representing several generations (number which remains to be determined).
Pictures have kindly been provided by Dr D Jurc (SFI) and can be viewed on the EPPO gallery: http://photos.eppo.org/index.php/album/629-ophiomyia-kwansonis-ophokw-
Dissemination: Adults can fly but no details are available on their flying capacities. Over long distances, movement of infested plants is probably an important pathway. In addition, Hemerocallis spp. with their numerous cultivars are quite popular in gardening and it is likely that amateurs are actively exchanging or trading planting material. Plants are often multiplied vegetatively and sold bare-rooted with 1 or 2 crowns including short green leafy parts which could carry eggs, larvae or pupae. Seeds are not likely to be a pathway.
Pathway: Plants for planting of Hemerocallis spp. from countries where O. kwansonis occurs.
Possible risks: Hemerocallis spp. are widely planted in the EPPO region for ornamental purposes in parks and gardens. However, more data would be needed on the economic importance of its production and trade in the EPPO region. Although it seems that O. kwansonis does not kill Hemerocallis spp., attacked plants can be severely disfigured which reduces their economic value. Young larvae and eggs are virtually invisible in plant tissue and may easily escape detection in nurseries and consignments. For the moment, no chemical methods have been tested against this insect and no biological control agents have been identified, which renders its eradication/containment very difficult once it has been introduced. A rapid PRA has been conducted in the United Kingdom which pointed out that O. kwansonis has the potential to seriously decrease the quality of marketed crops, and that import of Hemerocallis from the USA and Asia was not regulated, thus leaving a possibility for entry. Therefore, phytosanitary measures (e.g. requirements that Hemerocallis plants should come from an area free from the pest) would be most effective to prevent its entry into countries which are still free from it. Considering the invasive behaviour of this leafminer, it seems desirable to prevent its further spread within the EPPO region.
EPPO RS 2013/010
Panel review date: -
Entry date 2013-01
Anonymous (2012) Daylily leafminer recently detected in US. American Nurseryman (January), p 20.
Jurc M, Černý M, Jurc D (2012) [First record of alien pest Ophiomyia kwansonis (Diptera: Agromyzidae) in Europe and its phytosanitary significance]. Šumarski List 9–10(136), 501–507 (in Croatian). http://www.sumari.hr/sumlist/pdf/201205010.pdf
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Fera (2012) Rapid Pest Risk Analysis for Ophiomyia kwansonis (daylily leafminer). http://www.fera.defra.gov.uk/plants/plantHealth/pestsDiseases/documents/ophiomyia.pdf
Florida Department of Agriculture and Consumer Services. Pest Alert: Daylily leafminer Ophiomyia kwansonis Sasakawa (Diptera: Agromyzidae), new to North America, including Florida by Steck GJ & Williams GL (dated 2012-05-22). http://www.freshfromflorida.com/pi/pest-alerts/pdf/ophiomyia-kwansonis.pdf
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