Introduced and native parasitoids of Phyllocnistis citrella Stainton in Greece: short term post-release evaluation

Abstract

The Citrus Leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is considered an important pest of citrus, damaging mainly nursery plants. In Greece it was first recorded on the island of Rhodes in 1995 and rapidly spread to all citrus growing areas of the country. Due to its wide expansion and damage, efforts were initiated to control this pest with biological control agents. For this purpose, a number of exotic parasitoids, such as Citrostichus phyllocnistoides (Narayanan), Quadrastichus sp. Girault and Semielacher petiolata (Girault) (Hymenoptera: Eulophidae), were introduced, reared in insectaries and released in several regions of Greece. The species composition and the seasonal abundance of the native parasitoids, as well as the recovery of the released parasitoids, were investigated in weekly samplings during 1998 and 1999 in a citrus orchard in Argolis district. Results showed that among the released parasitoids, only C. phyllocnistoides was recovered. Among the native parasitoids, Neochrysocharis formosa (Westwood), Pnigalio pectinicornis (L.) and Cirrospilus sp. Westwood (Hymenoptera: Eulophidae) were identified. The most abundant parasitoid species was the exotic C. phyllocnistoides. The highest percent of parasitism in 1999 increased approximately by 46% compared with that of the previous year. The percent of parasitism increased to its maximum level during November, at the end of the sampling period in both years, when the population density of C. phyllocnistoides was high.