Agricultura 5(2007)
Copyright 2007 by University of Maribor
Trichopoda pennipes F. (Diptera, Tachinidae):
A new natural enemy of Nezara viridula (L.)
in Slovenia – short communication
Maarten de GrOOT, Meta VIrAnT-DOBerleT and alenka žunič
Dept. of Entomology, National Institute of Biology, Večna pot 111, SI-1000 Ljubljana, Slovenia
Following the introduction of Nezara viridula (L.) into North America, the native parasitoid tachinid fy Trichopoda pennipes Fabr. became one of its natural enemies (Jones 1988). Approximately ffteen years ago, T. pennipes was accidentally introduced into Italy in the vicinity of Rome, probably by overseas shipments carrying N viridula (Co-lazza et al. 1996). It has since spread rapidly across the Italian peninsula, colonizing frst the coastal areas (Solarno et al 2002) and is nowadays relatively common in Italy. Since Nezara viridula is a good disperser (Knight and Gurr 2007), it was only a matter of time before T. pennipes was to be found in Slovenia.
The members of the Department of Entomology of the National Institute of Biology have been collecting N viridula since the beginning of the nineties in the area of Koper (x = 43065.9, y = 401387.3) and Piran (x = 43182, y = 389843), in 2005 also in Mirensko polje (feld of Miren) near Nova Gorica (x = 84069, y = 391793) and in 2006 in Manče in the Vipava valley (x = 75669, y = 417956). N. viridula was collected by beating bushes (not always: not in Manče or Miren) and caught from the beating sheet. Both adults and 4th instar nymphs were collected.
T. pennipes was found in Koper, Piran and the area of Nova Gorica. The frst parasitized animals in Koper were found in the autumn of 2003. In the years 2004 and 2005 parasitized animals were collected also in Piran. However, in 2006, we collected in Piran only one not-parasitized pair of N. viridula. In the area of Nova Gorica we found T. pennipes in 2005.
On 18 October 2006, we found in Koper that 77 of the 497 adult N. viridula were parasitized. Of these, 24 females (approx. 0% of the female population) and 53 males (ap-prox. 20% of the male population) were parasitized with T. pennipes. This is in accordance with the parasitization rate during the early years of the introduction into Italy (Solarno et al. 2002). Under laboratory conditions (20-23°C, 18L:8N), 9 maggots emerged from 25 parasitized females. The duration of the pupal stage ranged from 4 to 9 days, only 0 adults emerged.
The distribution of T. pennipes is expected to correspond to be the same as the distribution of its host, N viridula, which covers the Primorska region as far north as Tolmin (pers. comm. A. Gogala and M. Gogala).
The consequences of the introduction of such an alien parasitoid or predatory species on the native fauna are well
Corresponding author: maarten.degroot@nib.si
surveyed and can have the potential to be disastrous (Johnson et al 2005, Koch 2003). In Italy, T. pennipes was not found to have any hosts other than N viridula (Solarno et al. 2002). However, related Trichopoda species introduced to Australia and Hawaii were found to be also attacking native pentatomid species (Sands and Coombs 1999, Johnson et al. 2005).
Although it has been shown that population numbers of the economically important pest N viridula can decline dramatically due to Trichopoda parasitoids (Coombs 2002), it has to be taken into account that T. pennipes is a gener-alist and will probably not only affect the target host. We therefore, suggest monitoring this species; investigations of its distribution and its effect on  N. viridula and other pentatomid species are urgently needed.
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A NEW NATURAL ENEMY OF NEZARA VIRIDULA (L.) IN SLOVENIA
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Received: February 27, 2007; Accepted in fnal form: July 10, 2007
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