Ophelimus maskelli
Ophelimus maskelli
Ophelimus maskelli Ashmead (Hymenoptera: Eulophidae), commonly known as the Eucalyptus gall wasp, is a serious gall-inducing pest of Eucalyptus. Native to New South Wales, Australia, O. maskelli has spread and established itself in Europe, the Mediterranean, Middle East, Africa and has recently been recorded in North America (2014). Originally described as Pteroptrix maskelli in 1900, the gall wasp was reclassified in 1988 as part of the revision of Australasian Chalcidoidae by Boucek (1988).
Oviposition by O. maskelli induces single-blister like galls on the surface of leaves, holding a single egg. High gall density can lead to severe leaf damage, early leaf drop and in extreme cases complete defoliation of the tree. As with the movement of other Eucalyptus pests, O. maskelli has spread without the presence of any principal parasitoids or other natural enemies that occur naturally in Australia, leaving Eucalyptus spp. open to injury. Ophelimus maskelli is causing extensive damage in Eucalyptus plantations, particularly on E. camaldulensis across the Mediterranean and Middle East.
Ophelimus maskelli Ashmead (Hymenoptera: Eulophidae), commonly known as the Eucalyptus gall wasp, is a serious gall-inducing pest of Eucalyptus. Native to New South Wales, Australia, O. maskelli has spread and established itself in Europe, the Mediterranean, Middle East, Africa and has recently been recorded in North America (2014). Originally described as Pteroptrix maskelli in 1900, the gall wasp was reclassified in 1988 as part of the revision of Australasian Chalcidoidae by Boucek (1988).
Oviposition by O. maskelli induces single-blister like galls on the surface of leaves, holding a single egg. High gall density can lead to severe leaf damage, early leaf drop and in extreme cases complete defoliation of the tree. As with the movement of other Eucalyptus pests, O. maskelli has spread without the presence of any principal parasitoids or other natural enemies that occur naturally in Australia, leaving Eucalyptus spp. open to injury. Ophelimus maskelli is causing extensive damage in Eucalyptus plantations, particularly on E. camaldulensis across the Mediterranean and Middle East.
Description
Adults
Adults are black bodied and approximately 1 mm in length.The most distinct characteristic of O. maskelli is the presence of a single seta on the submarginal vein of the forewing.
Galls
Oviposition into the leaf epidermis induces a blister like gall that is round and uniform in size and shape (gall diameter 0.9 – 1.2 mm). Gall density can range from 11.5 – 36 galls/cm². Ophelimus maskelli develop in the single-cell galls on the leaf surface. Gall colouring appears as soon as the third instar larva develop (see table below).
Typically, galls exposed to sunlight are a bruised-red colour, whilst those in shaded areas can be a greenish-yellow colour.
Biology
The understanding of the biology and ecology for O. maskelli is still limited in Australia and in many of the newly established countries. Much of the biological data for O. maskelli comes from research from Israel, site of the original introduction.
Females lay on average 109 eggs on both the upper and lower sides of the leaf, however gall density is generally higher on the ventral side. Each oviposition puncture induces a gall, in which a single wasp develops. The females prefer to oviposit on an area of the leaf blade near the petiole, on large, immature green coloured leaves in the lower canopy of the tree. The optimum time for wasp development appears to be on leaves 30 to 40 days old, but can take place from 15 to 90 days after bud break. Development of the pre-imaginal stages within the galls requires 110 ± 19 d at 18 – 25°C after which the adults emerge. Studies have shown that the wasp has three generations per year in Israel. The first generation is in spring, followed by the second in summer and a third through autumn. Larvae overwinter in galls.
There are five wasp development phases that coincide with gall development, consisting of three larval instars, a non-feeding pupal stage and adult (see table below). The adult emerges by cutting a circular hole in the gall wall close to the plane of the leaf. In Israel, heavily galled leaves survived for approximately 70 days, whilst those free of galls had a longevity of around 243 days.
Five stages of wasp and gall development
|
Gall development |
Wasp development |
Development period |
Total days |
Stage 1 |
From oviposition, gall visibly develops on the leaf surface |
1st larval instar |
30 – 35 days |
30 |
Stage 2 |
Galls develops typical colour (green-yellow or red-purple hue) |
2nd larval instar |
15 – 25 days |
60 |
Stage 3 |
Gall reaches maximum size |
First stage of 3rdlarval instar |
16 – 27 days |
87 |
Stage 4 |
Larva reaches maximum size, pupates, filling entire gall chamber |
Pupa |
20 – 26 days |
113 |
Stage 5 |
Adult |
10 – 16 days |
129 |
Protasov et al. 2007
Description
Adults
Adults are black bodied and approximately 1 mm in length.The most distinct characteristic of O. maskelli is the presence of a single seta on the submarginal vein of the forewing.
Galls
Oviposition into the leaf epidermis induces a blister like gall that is round and uniform in size and shape (gall diameter 0.9 – 1.2 mm). Gall density can range from 11.5 – 36 galls/cm². Ophelimus maskelli develop in the single-cell galls on the leaf surface. Gall colouring appears as soon as the third instar larva develop (see table below).
Typically, galls exposed to sunlight are a bruised-red colour, whilst those in shaded areas can be a greenish-yellow colour.
Biology
The understanding of the biology and ecology for O. maskelli is still limited in Australia and in many of the newly established countries. Much of the biological data for O. maskelli comes from research from Israel, site of the original introduction.
Females lay on average 109 eggs on both the upper and lower sides of the leaf, however gall density is generally higher on the ventral side. Each oviposition puncture induces a gall, in which a single wasp develops. The females prefer to oviposit on an area of the leaf blade near the petiole, on large, immature green coloured leaves in the lower canopy of the tree. The optimum time for wasp development appears to be on leaves 30 to 40 days old, but can take place from 15 to 90 days after bud break. Development of the pre-imaginal stages within the galls requires 110 ± 19 d at 18 – 25°C after which the adults emerge. Studies have shown that the wasp has three generations per year in Israel. The first generation is in spring, followed by the second in summer and a third through autumn. Larvae overwinter in galls.
There are five wasp development phases that coincide with gall development, consisting of three larval instars, a non-feeding pupal stage and adult (see table below). The adult emerges by cutting a circular hole in the gall wall close to the plane of the leaf. In Israel, heavily galled leaves survived for approximately 70 days, whilst those free of galls had a longevity of around 243 days.
Distribution
Ophelimus maskelli has established itself as an invasive species across Europe, Asia, the Middle East, Mediterranean, Africa and North America. The probable cause of introduction into the Euro-Mediterranean areas, and the subsequent movement across the globe, is through trade of its host (Eucalyptus sp.). It is highly likely that O. maskelli will establish itself in new parts of the world via this method.
Distribution of O. maskelli parasitoid Closterocerus chamaeleon
Distribution
Ophelimus maskelli has established itself as an invasive species across Europe, Asia, the Middle East, Mediterranean, Africa and North America. The probable cause of introduction into the Euro-Mediterranean areas, and the subsequent movement across the globe, is through trade of its host (Eucalyptus sp.). It is highly likely that O. maskelli will establish itself in new parts of the world via this method.
Host Trees
The most susceptible species to O. maskelli attack are Eucalyptus camaldulensis and E. tereticornis (= umbellate Smith). Host testing of 84 eucalyptus species, determined that 14 were suitable hosts for O. maskelli. Tests revealed that those belonging to the Exsertaria section of the genus are at greater risk of injury from O. maskelli than those in the Latoangulata and Maidenaria sections. Susceptible species include:
- E. botryoides
- E. bridgesiana
- E. camaldulensis
- E. cinerea
- E. globulus
- E. grandis
- E. gunii
- E. nicholii
- E. pulverulenta
- E. robusta
- E. rudis
- E. saligna
- E. tereticornis
- E. viminalis
Ophelimus maskelli poses a significant threat to hardwood production in the Mediterranean regions and the Middle East where E. camaldulensis is one of the most economically important trees grown in forestry plantations.
Host Trees
The most susceptible species to O. maskelli attack are Eucalyptus camaldulensis and E. tereticornis (= umbellate Smith). Host testing of 84 eucalyptus species, determined that 14 were suitable hosts for O. maskelli. Tests revealed that those belonging to the Exsertaria section of the genus are at greater risk of injury from O. maskelli than those in the Latoangulata and Maidenaria sections. Susceptible species include:
- E. botryoides
- E. bridgesiana
- E. camaldulensis
- E. cinerea
- E. globulus
- E. grandis
- E. gunii
- E. nicholii
- E. pulverulenta
- E. robusta
- E. rudis
- E. saligna
- E. tereticornis
- E. viminalis
Ophelimus maskelli poses a significant threat to hardwood production in the Mediterranean regions and the Middle East where E. camaldulensis is one of the most economically important trees grown in forestry plantations.
Damage
As with other successful eucalyptus pest invaders, O. maskelli has moved unaccompanied by its principal natural enemies. Populations were free from pressure by naturally occurring predators and parasitoids in the newly-established locations that are commonly associated with the gall wasp in Australia. In favourable conditions O. maskelli populations can reach epidemic levels. The entire leaf surface can be covered in small blister like galls ranging from a red-bruised colour to a yellow-green hue. Leaves bearing greater than 50 galls live considerable less in comparison to those without galls.
Heavy galling in Eucalyptus trees causes serious injury in the form of premature leaf drop, occurring soon after wasp emergence. Heavily injured trees are revealed by the desiccation of large parts of their crown and canopy, as a result of leaf shedding. Continual attack by O. maskelli can cause the death of young and newly planted trees. In a severe case from Israel, 80 year old E. camaldulensis trees shed their foliage to near complete defoliation. As a result, E. camaldulensis planting ceased for a period in Israel. There have also been instances where mass emergence of O. maskelli in spring have reached such high densities that ‘clouds’ of wasps cause nuisance to human activities.
Damage
As with other successful eucalyptus pest invaders, O. maskelli has moved unaccompanied by its principal natural enemies. Populations were free from pressure by naturally occurring predators and parasitoids in the newly-established locations that are commonly associated with the gall wasp in Australia. In favourable conditions O. maskelli populations can reach epidemic levels. The entire leaf surface can be covered in small blister like galls ranging from a red-bruised colour to a yellow-green hue. Leaves bearing greater than 50 galls live considerable less in comparison to those without galls.
Heavy galling in Eucalyptus trees causes serious injury in the form of premature leaf drop, occurring soon after wasp emergence. Heavily injured trees are revealed by the desiccation of large parts of their crown and canopy, as a result of leaf shedding. Continual attack by O. maskelli can cause the death of young and newly planted trees. In a severe case from Israel, 80 year old E. camaldulensis trees shed their foliage to near complete defoliation. As a result, E. camaldulensis planting ceased for a period in Israel. There have also been instances where mass emergence of O. maskelli in spring have reached such high densities that ‘clouds’ of wasps cause nuisance to human activities.
Monitoring
The exact distribution of O. maskelli across a range of countries, particularly in countries where the wasps is recently established, is limited. That new recordings have recently been confirmed from North America and South Africa indicates that O. maskelli is continuing to spread. What is unclear is the limit of the Eucalyptus gall wasps establishment potential. Green sticky traps are an effective and affordable way to monitor for the presence and movement of O. maskelli and parasitoids, and the rate and distribution of spread can be measured through annual surveys.
Monitoring
The exact distribution of O. maskelli across a range of countries, particularly in countries where the wasps is recently established, is limited. That new recordings have recently been confirmed from North America and South Africa indicates that O. maskelli is continuing to spread. What is unclear is the limit of the Eucalyptus gall wasps establishment potential. Green sticky traps are an effective and affordable way to monitor for the presence and movement of O. maskelli and parasitoids, and the rate and distribution of spread can be measured through annual surveys.
Control
Chemical control
Chemical control of O. maskelli is still limited. In young and small trees, application of systemic neonicotinoids such as thiacloprid and acetamiprid have proven to provide some protection against attack. In the nursery, application of Kaolin to young trees has provided some protection against O. maskelli attack. Kaolin, (Al2Si2O5 (OH)4), is a white porous, non-swelling, non-abrasive clay product that when applied, causes the treated surface to become hard, making it less suitable for oviposition. The white particle film hides the colour of the leaf, reducing host recognition without an interference to photosynthesis or stomatal conductance.
Biological control
Ophelimus maskelli populations were free from parasitoid pressure In newly established areas of the Mediterranean and the Middle East O. maskelli popultions were free from parasitoid pressure, with no observation’s of attack from native species either. In 2003 the Volcani Center of Bet Dagan (Israel) and CSIRO (Australia) initiated a biological control program to search for natural enemies of O. maskelli in Australia for possible introduction into Israel. Three parasitic wasps were found Closterocerus chamaeleon (Girault) (Hymenoptera: Eulophidae: Enedontinae), Stethynium ophelimi (Huber) and S. breviovipositer (Huber) (Mymaridae).
Approximately 12,000 C. chamaeleon adults were released in Israel from 2005 to 2006, which lowered O. maskelli population densities within one year of release. It has demonstrated its extreme mobility by occupying areas 120km away from its original release location one year later. Closterocerus chamaeleon is most active during the winter months when O. maskelli development has slowed. Stethynium ophelimi was reared and released in conjunction with C. chamaeleon, however subsequent surveys post release failed to recover large numbers of the parasitoid. Closterocerus chamaeleon has been released in Israel and Italy, and has been detected in Algeria, Spain, Turkey, Portugal, Tunisia and South Africa.
Control
Chemical control
Chemical control of O. maskelli is still limited. In young and small trees, application of systemic neonicotinoids such as thiacloprid and acetamiprid have proven to provide some protection against attack. In the nursery, application of Kaolin to young trees has provided some protection against O. maskelli attack. Kaolin, (Al2Si2O5 (OH)4), is a white porous, non-swelling, non-abrasive clay product that when applied, causes the treated surface to become hard, making it less suitable for oviposition. The white particle film hides the colour of the leaf, reducing host recognition without an interference to photosynthesis or stomatal conductance.
Biological control
Ophelimus maskelli populations were free from parasitoid pressure In newly established areas of the Mediterranean and the Middle East O. maskelli popultions were free from parasitoid pressure, with no observation’s of attack from native species either. In 2003 the Volcani Center of Bet Dagan (Israel) and CSIRO (Australia) initiated a biological control program to search for natural enemies of O. maskelli in Australia for possible introduction into Israel. Three parasitic wasps were found Closterocerus chamaeleon (Girault) (Hymenoptera: Eulophidae: Enedontinae), Stethynium ophelimi (Huber) and S. breviovipositer (Huber) (Mymaridae).
Approximately 12,000 C. chamaeleon adults were released in Israel from 2005 to 2006, which lowered O. maskelli population densities within one year of release. It has demonstrated its extreme mobility by occupying areas 120km away from its original release location one year later. Closterocerus chamaeleon is most active during the winter months when O. maskelli development has slowed. Stethynium ophelimi was reared and released in conjunction with C. chamaeleon, however subsequent surveys post release failed to recover large numbers of the parasitoid. Closterocerus chamaeleon has been released in Israel and Italy, and has been detected in Algeria, Spain, Turkey, Portugal, Tunisia and South Africa.
Aytar, F 2006,’ Natural history, distribution and hosts of Eucalyptus gall wasps in Turkey’, Department of Entomology, Mersin Regional Forest Directorate.
Aytar, F, Dagdas, S & Duran, C 2011,’ Australian insects affecting Eucalyptus species in Turkey’, Silva Lusitana, 41-47.
Borrajo, P, López, MA, Ocete, R, López, G & Ruiz, F 2008,’ First report of Closterocerus chamaeleon Girault (Hymenoptera, Eulophidae) parasitoid of Ophelimus maskelli Ashmead (Hymenoptera, Eulophidae) in Huelva (SW Spain)’, Boletin de Sanidad Vegetal, Plagas, vol. 34 (3), 383-385.
Branco, M, Boavida, C, Durand, N, Franco, JC & Mendel, Z 2008,’ Presence of the Eucalyptus gall was Ophelimus maskelli and its parasitoid Closterocerus chamaeleon in Portugal: first record, geographic distribution and host preference’, Phytoparasitica, vol. 54, 37-51.
Burks, RA, Mottern, JL, Waterworth, R & Paine, TD 2015,’ First report of the Eucalyptus gall wasp, Ophelimus maskelli (Hymenoptera: Eulophidae), and invasive pest on Eucalyptus, from the Western Hemisphere’, Zootaxa, vol. 3926 (3), 448-450.
Dhahri, S, Ben Jamaa, ML & Lo Verde, G 2010,’ First record of Leptocybe invasa and Ophelimus maskelli Eucalyptus gall wasp in Tunisia’, Tunisian Journal of Plant Protection, vol. 5, 229-234.
Doganlar, M & Mendel, Z 2007,’ First record of the eucalyptus gall wasp Ophelimus maskelliand its parasitoid, Closterocerus chamaeleon, in Turkey’, Phytoparasitica, vol. 35, 333-335.
Caleca, V 2010,’ First record in Algeria of two Eulophidae wasps: Closterocerus chamaeleon(Girault) and its host, the eucalyptus gall wasp Ophelimus maskelli (Ashmead) (Hymenoptera Eulophidae)’, Naturalist siciliana, IV, XXXIV (1-2) 201-206.
Caleca, V, Lo Verde, G, Rizzo, MC & Rizzo, R 2011,’ Dispersal rate and parasitism by Closterocerus chamaeleon (Girault) after its release in Sicily to control Ophelimus maskelli(Ashmead) (Hymenoptera, Eulophidae)’, Biological Control, vol. 57, 66-73.
EPPO Global Database 2014, European and Mediterranean Plant Protection Organization, Ophelimus maskelli.
Huber, JT, Mendel, Z, Protasov, A & La Salle, J 2006,’ Two new Australian species of Stethynium (Hymenoptera : Mymaridae), larval parasitoids of Ophelimus maskelli (Ashmead) (Hymenoptera : Eulophidae) on Eucalyptus’, Journal of Natural History, vol. 40, 1909-1921.
Invasive Species Compendium: Datasheets, maps, images abstracts and full texts on invasive species of the world, 2015, Ophelimus maskelli Eucalyptus gall wasp.
Laudonia, S, Viggiani, G & Sasso, R 2006,’ Exotic parasitoids to the aid of eucalypts’, Nuova introduzione in Italia: parassitoide esotico in aiuto degli eucalypti, vol. 62, 74.
Lo Verde, G, Dhahri, S & Ben Jamaa, ML 2010,’ First record in Tunisia of Closterocerus chamaeleon (Girault) parasitoid of the Eucalyptus gall was Ophelimus maskelli (Ashmead) (Hymenoptera Eulophidae)’, Naturalistica Siciliana, IV, XXIV, (1-2), 207-210.
Lo Verde, G, Rizzo, R, Barraco, G & Lombardo, A 2011,’ Effects of Kaolin on Ophelimus maskelli (Hymenoptera: Eulophidae) in Laboratory and Nursery Experiments’, Journal of Economic Entomology, vol. 104, 180-187.
Mendel, Z, Protasov, A, Blumberg, D, Brand, D, Saphir, N, Madar, Z & La Salle, J 2007,’ Release and recovery of parasitoids of the eucalyptus gall wasp Ophelimus maskelli in Israel,’ Phytoparasitica, vol. 35, 330-332.
Mifsud, D 2012,’ Leptocybe invasa Fisher & La Salle, 2004 and Ophelimus maskelli Haliday, 1844 – two new records of gall forming Eulophidae from Malta (Hymenoptera, Chalcidoidae)’, Bulletin of the Entomological Society of Malta, vol. 5, 189-193.
Protasov, A, Blumberg, D, Brand, D, Salle, Jl & Mendel, Z 2007,’ Biological control of the eucalyptus gall wasp Ophelimus maskelli (Ashmead): taxonomy and biology of the parasitoid species Closterocerus chamaeleon (Girault), with information on its establishment in Israel’, Biological Control, vol. 42, 196-206.
Protasov, A, La Salle, J, Blumberg, D, Brand, D, Saphir, N, Assael, F, Fisher, N & Mendel, Z 2007,’ Biology, revised taxonomy and impact on host plants of Ophelimus maskelli, an invasive gall inducer on Eucalyptus spp. in the Mediterranean area’, Phytoparasitica, vol. 35, 50-76.
Rizzo, MC, Verde, Gl, Rizzo, R, Buccellato, V & Caleca, V 2006,’ Introduction of Closterocerussp. in Sicily for biological control of Ophelimus maskelli Ashmead (Hymenoptera Eulophidae) invasive gall inducer on eucalypt trees’, Bollettino di Zoologia agraria e Bachicoltura Serie II,vol.38, 237–248.
Universal Chalcidoidea Database, Distribution References: Closterocerus chamaeleon Girault, Natural History Museum, London.
Aytar, F 2006,’ Natural history, distribution and hosts of Eucalyptus gall wasps in Turkey’, Department of Entomology, Mersin Regional Forest Directorate.
Aytar, F, Dagdas, S & Duran, C 2011,’ Australian insects affecting Eucalyptus species in Turkey’, Silva Lusitana, 41-47.
Borrajo, P, López, MA, Ocete, R, López, G & Ruiz, F 2008,’ First report of Closterocerus chamaeleon Girault (Hymenoptera, Eulophidae) parasitoid of Ophelimus maskelli Ashmead (Hymenoptera, Eulophidae) in Huelva (SW Spain)’, Boletin de Sanidad Vegetal, Plagas, vol. 34 (3), 383-385.
Branco, M, Boavida, C, Durand, N, Franco, JC & Mendel, Z 2008,’ Presence of the Eucalyptus gall was Ophelimus maskelli and its parasitoid Closterocerus chamaeleon in Portugal: first record, geographic distribution and host preference’, Phytoparasitica, vol. 54, 37-51.
Burks, RA, Mottern, JL, Waterworth, R & Paine, TD 2015,’ First report of the Eucalyptus gall wasp, Ophelimus maskelli (Hymenoptera: Eulophidae), and invasive pest on Eucalyptus, from the Western Hemisphere’, Zootaxa, vol. 3926 (3), 448-450.
Dhahri, S, Ben Jamaa, ML & Lo Verde, G 2010,’ First record of Leptocybe invasa and Ophelimus maskelli Eucalyptus gall wasp in Tunisia’, Tunisian Journal of Plant Protection, vol. 5, 229-234.
Doganlar, M & Mendel, Z 2007,’ First record of the eucalyptus gall wasp Ophelimus maskelliand its parasitoid, Closterocerus chamaeleon, in Turkey’, Phytoparasitica, vol. 35, 333-335.
Caleca, V 2010,’ First record in Algeria of two Eulophidae wasps: Closterocerus chamaeleon(Girault) and its host, the eucalyptus gall wasp Ophelimus maskelli (Ashmead) (Hymenoptera Eulophidae)’, Naturalist siciliana, IV, XXXIV (1-2) 201-206.
Caleca, V, Lo Verde, G, Rizzo, MC & Rizzo, R 2011,’ Dispersal rate and parasitism by Closterocerus chamaeleon (Girault) after its release in Sicily to control Ophelimus maskelli(Ashmead) (Hymenoptera, Eulophidae)’, Biological Control, vol. 57, 66-73.
EPPO Global Database 2014, European and Mediterranean Plant Protection Organization, Ophelimus maskelli.
Huber, JT, Mendel, Z, Protasov, A & La Salle, J 2006,’ Two new Australian species of Stethynium (Hymenoptera : Mymaridae), larval parasitoids of Ophelimus maskelli (Ashmead) (Hymenoptera : Eulophidae) on Eucalyptus’, Journal of Natural History, vol. 40, 1909-1921.
Invasive Species Compendium: Datasheets, maps, images abstracts and full texts on invasive species of the world, 2015, Ophelimus maskelli Eucalyptus gall wasp.
Laudonia, S, Viggiani, G & Sasso, R 2006,’ Exotic parasitoids to the aid of eucalypts’, Nuova introduzione in Italia: parassitoide esotico in aiuto degli eucalypti, vol. 62, 74.
Lo Verde, G, Dhahri, S & Ben Jamaa, ML 2010,’ First record in Tunisia of Closterocerus chamaeleon (Girault) parasitoid of the Eucalyptus gall was Ophelimus maskelli (Ashmead) (Hymenoptera Eulophidae)’, Naturalistica Siciliana, IV, XXIV, (1-2), 207-210.
Lo Verde, G, Rizzo, R, Barraco, G & Lombardo, A 2011,’ Effects of Kaolin on Ophelimus maskelli (Hymenoptera: Eulophidae) in Laboratory and Nursery Experiments’, Journal of Economic Entomology, vol. 104, 180-187.
Mendel, Z, Protasov, A, Blumberg, D, Brand, D, Saphir, N, Madar, Z & La Salle, J 2007,’ Release and recovery of parasitoids of the eucalyptus gall wasp Ophelimus maskelli in Israel,’ Phytoparasitica, vol. 35, 330-332.
Mifsud, D 2012,’ Leptocybe invasa Fisher & La Salle, 2004 and Ophelimus maskelli Haliday, 1844 – two new records of gall forming Eulophidae from Malta (Hymenoptera, Chalcidoidae)’, Bulletin of the Entomological Society of Malta, vol. 5, 189-193.
Protasov, A, Blumberg, D, Brand, D, Salle, Jl & Mendel, Z 2007,’ Biological control of the eucalyptus gall wasp Ophelimus maskelli (Ashmead): taxonomy and biology of the parasitoid species Closterocerus chamaeleon (Girault), with information on its establishment in Israel’, Biological Control, vol. 42, 196-206.
Protasov, A, La Salle, J, Blumberg, D, Brand, D, Saphir, N, Assael, F, Fisher, N & Mendel, Z 2007,’ Biology, revised taxonomy and impact on host plants of Ophelimus maskelli, an invasive gall inducer on Eucalyptus spp. in the Mediterranean area’, Phytoparasitica, vol. 35, 50-76.
Rizzo, MC, Verde, Gl, Rizzo, R, Buccellato, V & Caleca, V 2006,’ Introduction of Closterocerussp. in Sicily for biological control of Ophelimus maskelli Ashmead (Hymenoptera Eulophidae) invasive gall inducer on eucalypt trees’, Bollettino di Zoologia agraria e Bachicoltura Serie II,vol.38, 237–248.
Universal Chalcidoidea Database, Distribution References: Closterocerus chamaeleon Girault, Natural History Museum, London.