Addition of Leptocybe invasa to the EPPO Alert List
The EPPO Secretariat would like to draw the attention of Mediterranean countries to the current spread of insects damaging eucalyptus foliage. Some insect psyllids have already been added to the EPPO Alert List (Ctenarytaina spatulata, and previously Glycaspis brimblecombei) but it was felt that leaf gall-inducing insects such as Leptocybe invasa (Hymenoptera: Eulophidae) could also present a risk to eucalyptus nurseries and plantations. At the moment, only L. invasa is being added to the Alert List, but there are other species (e.g. Ophelimus eucalypti, O. maskelli, Aprostocetus) which could present similar risks.
Leptocybe invasa (Hymenoptera: Eulophidae – Blue gum chalcid)
Why: Leptocybe invasa is a newly described species which is currently spreading in many countries around the Mediterranean Basin and in Africa, causing damage to eucalyptus young plantations and nurseries.
EPPO region: Algeria, France (including Corsica), Israel, Italy, Jordan, Morocco, Spain, Turkey.
Africa: Algeria, Jordan, Kenya, Morocco, Syria, Tanzania, Uganda.
Asia: Iran, Israel, Thailand, Turkey, Vietnam.
Oceania: L. invasa is thought to originate from Australia, but its situation in this country is unknown.
On which plants: L. invasa attacks many Eucalyptus species (e.g. E. botryoides, E. bridgesiana, E. camaldulensis, E. globulus, E. gunii, E. grandis, E. saligna, E. maidenii, E. robusta, E. tereticornis, E. viminalis).
Damage: L. invasa causes galls on the mid-ribs, petioles and stems of new shoots of eucalyptus trees. Heavy infestations can lead to deformed leaves and shoots, and a growth reduction of the tree. Serious damage to young plantations and nursery seedlings has been reported but tree mortality has apparently not been observed. Adult females (1.1-1.4 mm) insert their eggs in the epidermis of young leaves, on both sides of the mid-rib, in the petioles and in the parenchyma of twigs. Larvae develop inside round galls (about 2.7 mm wide), adults then emerge leaving round exit holes. So far, only females have been observed (reproducing by parthenogenesis), with the exception of one record describing males in Turkey. In Iran, Israel and Turkey, two to three overlapping generations per year have been observed.
Dissemination: Adult can fly but no data is available on natural spread of this insect. Trade of plants for planting can move the pest over long distances.
Pathway: Plants for planting of eucalyptus, cut foliage?
Possible risks: Eucalyptus are widely grown around the Mediterranean Basin for forestry and ornamental purposes. Currently, no control measures are available against L. invasa, although research is being carried out to identify potential natural enemies. Chemical control may be available in nurseries but will be more difficult in natural environments. Much data is lacking on the taxonomy, current geographical distribution, biology, and economic impact. It is felt that many species attacking eucalyptus foliage are being moved with trade, therefore more precautions would be needed when exchanging eucalyptus plants for planting.
EPPO RS 2006/190
Panel review date - Entry date 2006-09
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