Establishment of Neodryinus typhlocybae (Ashmead) (Hymenoptera: Dryinidae) in Sicilian lemon orchards.
The results of a classical biocontrol program against Metcalfa pruinosa (Say) (Homoptera: Flatidae) introducing the specific parasitoid Neodryinus typhlocybae (Ashmead) (Hymenoptera: Dryinidae) are reported. The antagonist was released in a 15-ha lemon orchard in Eastern Sicily where the infestation levels and the population dynamics of M. pruinosa have been monitored, on a fortnightly basis, since March 2004. One hundred adults of N. typhlocybae were released in an area of the orchard with a high density of the pest and where a Pittosporum hedge was planted. The periodical sampling revealed the presence of the first pupae of the parasitoid only after January 2006 on trees close to the release point. The parasitoid was then found at a density of 1-10 pupae per tree, up to 100m far from the release point. The diffuse presence of N. typhlocybae on Pittosporum is of particular interest because of the potential use of these hedge plants as reproductive refuge of the antagonist. In the 3 years of the survey the infestation levels on lemon trees, expressed as mean percentage of new shoots bearing more than one M. pruinosa instar, were respectively 13.71%, 27.56% and 25.09%. Further observations are still being conducted in Sicily in order to find other areas of presence of the dryinid as well as to evaluate its activity and efficacy in controlling the citrus flatid.