Agathis fuscipennis (Zetterstedt) (Hymenoptera Braconidae) was collected for the first time from larvae of the tomato leafminer
Abstract
Agathis fuscipennis (Zetterstedt) (Hymenoptera Braconidae) was collected for the first time from larvae of the tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera Gelechiidae) infesting Solanum nigrum (L.) plants in Tuscany (Central Italy). The knowledge about this parasitoid is still scarce. Its role in the biological or integrated control of T. absoluta remains to be evaluated.
Key words: Braconid, new host, Tuta absoluta.
Introduction
Tuta absoluta (Meyrick) (Lepidoptera Gelechiidae) is a moth native from South America, where it is an important pest of tomato crops (Filho et al., 2000; Gomide et al., 2001). In 2006 it was accidentally introduced in Spain (Urbaneja et al., 2007) from where it spread very quickly in many other countries of the western Paleartic Region (Desneux et al., 2010; EPPO, 2009a; 2009b; 2010; Ostrauskas and Ivinskis, 2010).
The tomato leafminer larvae feed inside the mesophyll tissue, hollowing it out. They can also penetrate young stems and fruits. Its damages are heavy both in greenhouse and in field crops. Although tomato (Lycopersicon esculentum Mill.) is the preferred host plant, larvae of T. absoluta can live also on other cultivated plants such as Solanum tuberosum L. (potato), Solanum melongena L. (aubergine), Solanum muricatum Aiton (sweet pepper), Nicotiana tabacum L. (tobacco), Phaseolus vulgaris L. (bean) and Physalis peruviana L. (cape gooseberry) (Desneux et al., 2010). On wild species, the larvae can be found on Datura stramonium L., Datura ferox L., Lycium chilense (Coralillo), Lycopersicum hirsutum L., Nicotiana glauca (Graham), Solanum lyratum Thumberg, Solanum puberulum Nuttal ex Seemann, Solanum nigrum L. (EPPO, 2007).
Chemical insecticides are still the main tool used for T. absoluta control both in South America and in Europe, although the mating disruption technique has given encouraging results (Filho et al., 2000). Furthermore there is an increasing interest in assessing the potential role of both native natural enemies and European endemic enemies in reducing the pest populations (Vivan et al., 2003; Arnó et al., 2010; Desneux et al., 2010).
Materials and methods
Observations were carried out in September - October of the years 2009 and 2010, at Capezzano Pianore (Lucca - Italy). In order to avoid the negative effects of insecticides sprays on entomophagous survival, leaves infested with T. absoluta were collected from plants of the wild host S. nigrum nearby of a tomato greenhouse heavily infested with the tomato leafminer. Both in 2009 and 2010, about 1000 leaves with mines, were cut and isolated from S. nigrum plants. This material was divided inside three plastic cages and maintained in the lab under standard conditions (23 ± 1 °C and 55 ± 10% RH) to allow the emergence of adults of both T. absoluta and eventual parasitoids. The leaves were left inside the cages until no more adults emerged and then they were counted.
Agathis fuscipennis (Zetterstedt) (Hymenoptera Braconidae) was identified using the key of imbolotti and van Achterberg (1999) in the laboratory of the Department of Terrestrial Zoology, Netherlands Centre for Biodiversity Naturalis at Leiden (The Netherlands).
T. absoluta adults were identified according to the keys and descriptions presented by Povolny (1994). The specimens of both species are conserved in the Department of Tree Science, Entomology and Plant Pathology “G. Scaramuzzi” of Pisa (Italy).
the wild host S. nigrum nearby of a tomato greenhouse heavily infested with the tomato leafminer. Both in 2009 and 2010, about 1000 leaves with mines, were cut and isolated from S. nigrum plants. This material was divided inside three plastic cages and maintained in the lab under standard conditions (23 ± 1 °C and 55 ± 10% RH) to allow the emergence of adults of both T. absoluta and eventual parasitoids. The leaves were left inside the cages until no more adults emerged and then they were counted.
Agathis fuscipennis (Zetterstedt) (Hymenoptera Braconidae) was identified using the key of imbolotti and van Achterberg (1999) in the laboratory of the Department of Terrestrial Zoology, Netherlands Centre for Biodiversity Naturalis at Leiden (The Netherlands).
T. absoluta adults were identified according to the keys and descriptions presented by Povolny (1994). The specimens of both species are conserved in the Department of Tree Science, Entomology and Plant Pathology “G. Scaramuzzi” of Pisa (Italy).
The entomophagous complex living on T. absoluta larvae in its native areas has been assessed while not very much is known about the parasitoids and predators in the new colonized areas. A list of new recorded enemies for Europe is summarized in the paper of Desneux et al. (2010). Among these, some undetermined species of Braconidae are reported. Different Braconids were found living on the South America tomato leafminer.
Pseudoapanteles dignus (Muesebeck) is reported as the main solitary larval parasitoid (about 30% of mean parasitization rate), although it can parasite also other Gelechiidae of economic importance (Cardona and Oatman, 1971; Sanchez et al., 2009).
Other Braconids are reported living on T. absoluta, belonging to the genus Bracon, Earinus, Apanteles, Diadegma, Orgilus, Chelonus, and also an Agathis sp. is mentioned (Desneux et al., 2010; Marchiori et al., 2004).
The first observation on A. fuscipennis refers to a limited period of time and to a restricted geographical area. It will be interesting to extend the survey in space and time for an evaluation of the role played by this parasitoid in the development of integrated and/or biological control protocols for T. absoluta.
Authors’Address:
Elisabetta ROSSI (corresponding author: erossi@agr.unipi.it), Augusto LONI, Department of Tree Science, Entomology and Plant Pathology “G. Scaramuzzi”, University of Pisa, via S. Michele degli Scalzi 2, 56124 Pisa, Italy; Kees VAN ACHTERBERG, Department of Terrestrial Zoology, Netherlands Centre for Biodiversity Naturalis, Postbus 9517, 2300 RA Leiden, The Netherlands. Received November 10, 2010. Accepted March 25, 2011.
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