Karaca, I. 1998 Parasitization efficacy of Aphytis melinus DeBach (Hymenoptera: Aphelinidae) as affected by host size and size distribution of Aonidiella aurantii (Maskell) (Homoptera: Diaspididae) in a lemon orchard.. Türkiye Entomoloji Dergisi 22: 2, 101-108.

Notes: Aonidiella aurantii is a major pest of citrus in the east Mediterranean region of Turkey. Aphytis melinus is the most common natural enemy of A. aurantii. In this study, host size and host size distribution of A. aurantii were examined on mature lemon trees to determine possible causes on efficacy of A. melinus observed in field. A. aurantii density was significantly higher on fruits (1.00/cm2) than on leaves (0.61/cm2), twigs (0.05/cm2) or trunks (0.01/cm2). Virgin females tended to be larger on fruits than on other plant parts, while size of second stage larvae was not affected by plant part. Significantly more A. aurantii were parasitized by A. melinus on fruits (12.6%) and leaves (8.6%) than on twigs (1.0%); none of the individuals on trunks were parasitized. Distribution analyses of A. aurantii scale cover size showed two distinct groups of host sizes; the larval stages ranging between 0.06-0.30 mm2 and the virgin females being 0.30-0.70 mm2 in size. About 54.2% of the total A. aurantii population comprised of individuals smaller than 0.30 mm2 and only 9.5% of them were parasitized. A. aurantii individuals larger than 0.40 mm2 were preferred for parasitization, but constituted only 20.4% of total population of which 52.3% were parasitized by A. melinus.