Takagi, K. 1983b [Establishment of Aphytis sp. and Physcus fulvus (Hymenoptera: Aphelinidae), the imported parasitoids of the arrowhead scale, Unaspis yanonensis (Hemiptera: Diaspidae), on citrus orchard in Japan.]. Bulletin of the Fruit Tree Research Station Series D (Kuchinotsu) (5): 93-110.

Notes: Two parasitoids, Aphytis sp. and Physcus fulvus, were introduced into Japan in 1980 from Chungking, China for biological control of the arrowhead scale. These parasitoids were established in the citrus groves of Kuchinotsu in western Japan and studied under laboratory conditions. The orchard (770 m-2) used consisted of satsuma mandarin trees on which the infestation of U. yanonenis was variable. The orchards were not sprayed with insecticides or fungicides during the previous two years. Five trees at a time were introduced into the orchards by introducing young potted trees with the arrowhead scale parasitized by the two parasitoids. The presumed number of P. fulvus and Aphytis sp. for each tree was 20 and 200, respectively. Three months after introduction of the potted trees, parasitism by Aphytis sp. was recorded as 48% and the parasites were distributed throughout the orchards. The rate of parasitism of P. fulvus was 23% after four months and the parasites were concentrated at the introduction point and adjacent trees.